From d2cba96e10ca39bb7954a2c3081710c5fed84c4b Mon Sep 17 00:00:00 2001
From: tophf <tophf@gmx.com>
Date: Tue, 26 Dec 2017 23:39:52 +0300
Subject: [PATCH] refactor CSSLint

* reduce linting delay
* parse mozformat in worker
* allow empty functions in 'filter:' property
  https://drafts.fxtf.org/filter-effects/#supported-filter-functions
* support comma-separated list in :lang()
* strip vendor prefix in isLiteral()
---
 .eslintignore                               |     1 +
 .eslintrc                                   |     4 +-
 edit.html                                   |     4 +-
 edit/edit.js                                |    25 +-
 edit/lint.js                                |    24 +-
 edit/source-editor.js                       |     6 +-
 edit/util.js                                |    23 +
 js/moz-parser.js                            |   254 +-
 js/prefs.js                                 |    12 +-
 js/usercss.js                               |    18 +-
 vendor-overwrites/csslint/csslint-loader.js |    35 +
 vendor-overwrites/csslint/csslint-worker.js | 11145 ------------------
 vendor-overwrites/csslint/csslint.js        |  1723 +++
 vendor-overwrites/csslint/parserlib.js      |  5963 ++++++++++
 14 files changed, 7908 insertions(+), 11329 deletions(-)
 create mode 100644 vendor-overwrites/csslint/csslint-loader.js
 delete mode 100644 vendor-overwrites/csslint/csslint-worker.js
 create mode 100644 vendor-overwrites/csslint/csslint.js
 create mode 100644 vendor-overwrites/csslint/parserlib.js

diff --git a/.eslintignore b/.eslintignore
index f1fc323f..8e747f5b 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -1,3 +1,4 @@
 vendor/
 vendor-overwrites/*
 !vendor-overwrites/colorpicker
+!vendor-overwrites/csslint
diff --git a/.eslintrc b/.eslintrc
index cc8956c0..159a4f12 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -239,13 +239,13 @@ rules:
   object-curly-spacing: [2, never]
   object-shorthand: [0]
   one-var-declaration-per-line: [1]
-  one-var: [0]
+  one-var: [2, {initialized: never}]
   operator-assignment: [2, always]
   operator-linebreak: [2, after, overrides: {"?": ignore, ":": ignore, "&&": ignore, "||": ignore}]
   padded-blocks: [0]
   prefer-numeric-literals: [2]
   prefer-rest-params: [0]
-  prefer-const: [1, {destructuring: any, ignoreReadBeforeAssign: true}]
+  prefer-const: [1, {destructuring: all, ignoreReadBeforeAssign: true}]
   quote-props: [0]
   quotes: [1, single, avoid-escape]
   radix: [2, as-needed]
diff --git a/edit.html b/edit.html
index 19375978..07f99b89 100644
--- a/edit.html
+++ b/edit.html
@@ -5,6 +5,7 @@
 
     <link href="global.css" rel="stylesheet">
     <link href="edit/edit.css" rel="stylesheet">
+    <link rel="stylesheet" href="msgbox/msgbox.css">
 
     <style id="firefox-transitions-bug-suppressor">
       /* restrict to FF */
@@ -22,7 +23,6 @@
     <script src="js/prefs.js"></script>
     <script src="js/localization.js"></script>
     <script src="js/script-loader.js"></script>
-    <script src="js/moz-parser.js"></script>
     <script src="js/storage-util.js"></script>
     <script src="content/apply.js"></script>
     <script src="edit/lint.js"></script>
@@ -37,6 +37,8 @@
     <script src="edit/codemirror-editing-hooks.js"></script>
     <script src="edit/edit.js"></script>
 
+    <script src="msgbox/msgbox.js" async></script>
+
     <link  href="vendor/codemirror/lib/codemirror.css" rel="stylesheet">
     <script src="vendor/codemirror/lib/codemirror.js"></script>
 
diff --git a/edit/edit.js b/edit/edit.js
index 1ce98056..f2bd4773 100644
--- a/edit/edit.js
+++ b/edit/edit.js
@@ -1,11 +1,12 @@
 /*
 global CodeMirror parserlib loadScript
 global CSSLint initLint linterConfig updateLintReport renderLintReport updateLinter
-global mozParser createSourceEditor
+global createSourceEditor
 global closeCurrentTab regExpTester messageBox
 global setupCodeMirror
 global beautify
 global initWithSectionStyle addSections removeSection getSectionsHashes
+global sectionsToMozFormat
 */
 'use strict';
 
@@ -415,7 +416,7 @@ function showMozillaFormat() {
 }
 
 function toMozillaFormat() {
-  return mozParser.format({sections: getSectionsHashes()});
+  return sectionsToMozFormat({sections: getSectionsHashes()});
 }
 
 function fromMozillaFormat() {
@@ -450,8 +451,24 @@ function fromMozillaFormat() {
   function doImport({replaceOldStyle = false}) {
     lockPageUI(true);
     new Promise(setTimeout)
-      .then(() => mozParser.parse(popup.codebox.getValue().trim()))
-      .then(sections => {
+      .then(() => {
+        const worker = linterConfig.worker.csslint;
+        if (!worker.instance) worker.instance = new Worker(worker.path);
+      })
+      .then(() => linterConfig.invokeWorker({
+        linter: 'csslint',
+        action: 'parse',
+        code: popup.codebox.getValue().trim(),
+      }))
+      .then(({sections, errors}) => {
+        // shouldn't happen but just in case
+        if (!sections.length && errors.length) {
+          return Promise.reject(errors);
+        }
+        // show the errors in case linting is disabled or stylelint misses what csslint has found
+        if (errors.length && prefs.get('editor.linter') !== 'csslint') {
+          showError(errors);
+        }
         removeOldSections(replaceOldStyle);
         return addSections(sections, div => setCleanItem(div, false));
       })
diff --git a/edit/lint.js b/edit/lint.js
index f7323464..31a17484 100644
--- a/edit/lint.js
+++ b/edit/lint.js
@@ -20,7 +20,7 @@ var linterConfig = {
     stylelint: 'editorStylelintConfig',
   },
   worker: {
-    csslint: {path: '/vendor-overwrites/csslint/csslint-worker.js'},
+    csslint: {path: '/vendor-overwrites/csslint/csslint-loader.js'},
     stylelint: {path: '/vendor-overwrites/stylelint/stylelint-bundle.min.js'},
   },
   allRuleIds: {
@@ -48,7 +48,7 @@ var linterConfig = {
       },
       onUpdateLinting(annotationsNotSorted, annotations, cm) {
         cm.endOperation();
-        updateLintReport(cm, 0);
+        updateLintReport(cm);
       },
     } : false;
   },
@@ -561,15 +561,17 @@ function setupLinterPopup(config) {
 
 function loadLinterAssets(name = linterConfig.getName()) {
   const worker = linterConfig.worker[name];
-  return !name || !worker || worker.instance ? Promise.resolve() :
-    loadScript((worker.instance ? [] : [
-      (worker.instance = new Worker(worker.path)),
-      `/edit/lint-defaults-${name}.js`,
-    ]).concat(CodeMirror.lint ? [] : [
+  if (!name || !worker) return Promise.resolve();
+  const scripts = [];
+  if (!worker.instance) {
+    worker.instance = new Worker(worker.path);
+    scripts.push(`/edit/lint-defaults-${name}.js`);
+  }
+  if (!CodeMirror.lint) {
+    scripts.push(
       '/vendor/codemirror/addon/lint/lint.css',
-      '/msgbox/msgbox.css',
       '/vendor/codemirror/addon/lint/lint.js',
-      '/edit/lint-codemirror-helper.js',
-      '/msgbox/msgbox.js'
-    ]));
+      '/edit/lint-codemirror-helper.js');
+  }
+  return scripts.length ? loadScript(scripts) : Promise.resolve();
 }
diff --git a/edit/source-editor.js b/edit/source-editor.js
index 4bdc53d8..b3e22a68 100644
--- a/edit/source-editor.js
+++ b/edit/source-editor.js
@@ -1,6 +1,6 @@
 /* global CodeMirror dirtyReporter initLint */
 /* global showToggleStyleHelp goBackToManage updateLintReportIfEnabled */
-/* global editors linterConfig updateLinter regExpTester mozParser */
+/* global editors linterConfig updateLinter regExpTester sectionsToMozFormat */
 /* global createAppliesToLineWidget messageBox */
 'use strict';
 
@@ -100,10 +100,10 @@ function createSourceEditor(style) {
 
   function setupNewStyle(style) {
     style.sections[0].code = ' '.repeat(prefs.get('editor.tabSize')) + '/* Insert code here... */';
-    let section = mozParser.format(style);
+    let section = sectionsToMozFormat(style);
     if (!section.includes('@-moz-document')) {
       style.sections[0].domains = ['example.com'];
-      section = mozParser.format(style);
+      section = sectionsToMozFormat(style);
     }
     const DEFAULT_CODE = `
       /* ==UserStyle==
diff --git a/edit/util.js b/edit/util.js
index 84b2e7d2..15c963ba 100644
--- a/edit/util.js
+++ b/edit/util.js
@@ -93,3 +93,26 @@ function dirtyReporter() {
 
   return wrap({add, remove, modify, clear, isDirty, onChange, has});
 }
+
+
+function sectionsToMozFormat(style) {
+  const propertyToCss = {
+    urls:        'url',
+    urlPrefixes: 'url-prefix',
+    domains:     'domain',
+    regexps:     'regexp',
+  };
+  return style.sections.map(section => {
+    let cssMds = [];
+    for (const i in propertyToCss) {
+      if (section[i]) {
+        cssMds = cssMds.concat(section[i].map(v =>
+          propertyToCss[i] + '("' + v.replace(/\\/g, '\\\\') + '")'
+        ));
+      }
+    }
+    return cssMds.length ?
+      '@-moz-document ' + cssMds.join(', ') + ' {\n' + section.code + '\n}' :
+      section.code;
+  }).join('\n\n');
+}
diff --git a/js/moz-parser.js b/js/moz-parser.js
index 1aa2aa47..28b07819 100644
--- a/js/moz-parser.js
+++ b/js/moz-parser.js
@@ -1,165 +1,109 @@
-/* global parserlib, loadScript */
+/* global parserlib */
 'use strict';
 
-// eslint-disable-next-line no-var
-var mozParser = (() => {
-  // direct & reverse mapping of @-moz-document keywords and internal property names
-  const propertyToCss = {urls: 'url', urlPrefixes: 'url-prefix', domains: 'domain', regexps: 'regexp'};
-  const CssToProperty = {'url': 'urls', 'url-prefix': 'urlPrefixes', 'domain': 'domains', 'regexp': 'regexps'};
+function parseMozFormat(mozStyle) {
+  const CssToProperty = {
+    'url':        'urls',
+    'url-prefix': 'urlPrefixes',
+    'domain':     'domains',
+    'regexp':     'regexps',
+  };
+  const parser = new parserlib.css.Parser();
+  const sectionStack = [{code: '', start: 0}];
+  const errors = [];
+  const sections = [];
 
-  function parseMozFormat(mozStyle) {
-    return new Promise((resolve, reject) => {
-      const parser = new parserlib.css.Parser();
-      const lines = mozStyle.split('\n');
-      const sectionStack = [{code: '', start: {line: 1, col: 1}}];
-      const errors = [];
-      const sections = [];
-
-      parser.addListener('startdocument', e => {
-        const lastSection = sectionStack[sectionStack.length - 1];
-        let outerText = getRange(lastSection.start, {line: e.line, col: e.col - 1});
-        const lastCmt = getLastComment(outerText);
-        const {endLine: line, endCol: col} = parser._tokenStream._token;
-        const section = {code: '', start: {line, col}};
-        // move last comment before @-moz-document inside the section
-        if (!/\/\*[\s\n]*AGENT_SHEET[\s\n]*\*\//.test(lastCmt)) {
-          if (lastCmt) {
-            section.code = lastCmt + '\n';
-            outerText = outerText.slice(0, -lastCmt.length);
-          }
-          outerText = outerText.match(/^\s*/)[0] + outerText.trim();
-        }
-        if (outerText.trim()) {
-          lastSection.code = outerText;
-          doAddSection(lastSection);
-          lastSection.code = '';
-        }
-        for (const f of e.functions) {
-          const m = f && f.match(/^([\w-]*)\((.+?)\)$/);
-          if (!m || !/^(url|url-prefix|domain|regexp)$/.test(m[1])) {
-            errors.push(`${e.line}:${e.col + 1} invalid function "${m ? m[1] : f || ''}"`);
-            continue;
-          }
-          const aType = CssToProperty[m[1]];
-          const aValue = unquote(aType !== 'regexps' ? m[2] : m[2].replace(/\\\\/g, '\\'));
-          (section[aType] = section[aType] || []).push(aValue);
-        }
-        sectionStack.push(section);
-      });
-
-      parser.addListener('enddocument', e => {
-        const section = sectionStack.pop();
-        const lastSection = sectionStack[sectionStack.length - 1];
-        const end = {line: e.line, col: e.col - 1};
-        section.code += getRange(section.start, end);
-        end.col += 2;
-        lastSection.start = end;
-        doAddSection(section);
-      });
-
-      parser.addListener('endstylesheet', () => {
-        // add nonclosed outer sections (either broken or the last global one)
-        const lastLine = lines[lines.length - 1];
-        const endOfText = {line: lines.length, col: lastLine.length + 1};
-        const lastSection = sectionStack[sectionStack.length - 1];
-        lastSection.code += getRange(lastSection.start, endOfText);
-        sectionStack.forEach(doAddSection);
-
-        if (errors.length) {
-          reject(errors);
-        } else {
-          resolve(sections);
-        }
-      });
-
-      parser.addListener('error', e => {
-        errors.push(e.line + ':' + e.col + ' ' +
-          e.message.replace(/ at line \d.+$/, ''));
-      });
-
-      parser.parse(mozStyle);
-
-      function getRange(start, end) {
-        const L1 = start.line - 1;
-        const C1 = start.col - 1;
-        const L2 = end.line - 1;
-        const C2 = end.col - 1;
-        if (L1 === L2) {
-          return lines[L1].substr(C1, C2 - C1 + 1);
-        } else {
-          const middle = lines.slice(L1 + 1, L2).join('\n');
-          return lines[L1].substr(C1) + '\n' + middle +
-            (L2 >= lines.length ? '' : ((middle ? '\n' : '') + lines[L2].substring(0, C2)));
-        }
+  parser.addListener('startdocument', e => {
+    const lastSection = sectionStack[sectionStack.length - 1];
+    let outerText = mozStyle.slice(lastSection.start, e.offset);
+    const lastCmt = getLastComment(outerText);
+    const section = {
+      code: '',
+      start: parser._tokenStream._token.offset + 1,
+    };
+    // move last comment before @-moz-document inside the section
+    if (!lastCmt.includes('AGENT_SHEET') &&
+        !lastCmt.includes('==') &&
+        !/==userstyle==/iu.test(lastCmt)) {
+      if (lastCmt) {
+        section.code = lastCmt + '\n';
+        outerText = outerText.slice(0, -lastCmt.length);
       }
+      outerText = outerText.match(/^\s*/)[0] + outerText.trim();
+    }
+    if (outerText.trim()) {
+      lastSection.code = outerText;
+      doAddSection(lastSection);
+      lastSection.code = '';
+    }
+    for (const {name, expr, uri} of e.functions) {
+      const aType = CssToProperty[name.toLowerCase()];
+      (section[aType] = section[aType] || []).push(uri || expr && expr.parts[0].value || '');
+    }
+    sectionStack.push(section);
+  });
 
-      function doAddSection(section) {
-        section.code = section.code.trim();
-        // don't add empty sections
-        if (
-          !section.code &&
-          !section.urls &&
-          !section.urlPrefixes &&
-          !section.domains &&
-          !section.regexps
-        ) {
-          return;
-        }
-        /* ignore boilerplate NS */
-        if (section.code === '@namespace url(http://www.w3.org/1999/xhtml);') {
-          return;
-        }
-        sections.push(Object.assign({}, section));
-      }
+  parser.addListener('enddocument', e => {
+    const section = sectionStack.pop();
+    const lastSection = sectionStack[sectionStack.length - 1];
+    section.code += mozStyle.slice(section.start, e.offset);
+    lastSection.start = e.offset + 1;
+    doAddSection(section);
+  });
 
-      function unquote(s) {
-        const first = s.charAt(0);
-        return (first === '"' || first === "'") && s.endsWith(first) ? s.slice(1, -1) : s;
-      }
+  parser.addListener('endstylesheet', () => {
+    // add nonclosed outer sections (either broken or the last global one)
+    const lastSection = sectionStack[sectionStack.length - 1];
+    lastSection.code += mozStyle.slice(lastSection.start);
+    sectionStack.forEach(doAddSection);
+  });
 
-      function getLastComment(text) {
-        let open = text.length;
-        let close;
-        while (open) {
-          // at this point we're guaranteed to be outside of a comment
-          close = text.lastIndexOf('*/', open - 2);
-          if (close < 0) {
-            break;
-          }
-          // stop if a non-whitespace precedes and return what we currently have
-          const tailEmpty = !text.substring(close + 2, open).trim();
-          if (!tailEmpty) {
-            break;
-          }
-          // find a closed preceding comment
-          const prevClose = text.lastIndexOf('*/', close);
-          // then find the real start of current comment
-          // e.g. /* preceding */  /* current /* current /* current */
-          open = text.indexOf('/*', prevClose < 0 ? 0 : prevClose + 2);
-        }
-        return text.substr(open);
-      }
-    });
+  parser.addListener('error', e => {
+    errors.push(`${e.line}:${e.col} ${e.message.replace(/ at line \d.+$/, '')}`);
+  });
+
+  parser.parse(mozStyle);
+  return {sections, errors};
+
+  function doAddSection(section) {
+    section.code = section.code.trim();
+    // don't add empty sections
+    if (
+      !section.code &&
+      !section.urls &&
+      !section.urlPrefixes &&
+      !section.domains &&
+      !section.regexps
+    ) {
+      return;
+    }
+    /* ignore boilerplate NS */
+    if (section.code === '@namespace url(http://www.w3.org/1999/xhtml);') {
+      return;
+    }
+    sections.push(Object.assign({}, section));
   }
 
-  return {
-    // Parse mozilla-format userstyle into sections
-    parse(text) {
-      return Promise.resolve(self.CSSLint || loadScript('/vendor-overwrites/csslint/csslint-worker.js'))
-        .then(() => parseMozFormat(text));
-    },
-    format(style) {
-      return style.sections.map(section => {
-        let cssMds = [];
-        for (const i in propertyToCss) {
-          if (section[i]) {
-            cssMds = cssMds.concat(section[i].map(v =>
-              propertyToCss[i] + '("' + v.replace(/\\/g, '\\\\') + '")'
-            ));
-          }
-        }
-        return cssMds.length ? '@-moz-document ' + cssMds.join(', ') + ' {\n' + section.code + '\n}' : section.code;
-      }).join('\n\n');
+  function getLastComment(text) {
+    let open = text.length;
+    let close;
+    while (open) {
+      // at this point we're guaranteed to be outside of a comment
+      close = text.lastIndexOf('*/', open - 2);
+      if (close < 0) {
+        break;
+      }
+      // stop if a non-whitespace precedes and return what we currently have
+      const tailEmpty = !text.substring(close + 2, open).trim();
+      if (!tailEmpty) {
+        break;
+      }
+      // find a closed preceding comment
+      const prevClose = text.lastIndexOf('*/', close - 2);
+      // then find the real start of current comment
+      // e.g. /* preceding */  /* current /* current /* current */
+      open = text.indexOf('/*', prevClose < 0 ? 0 : prevClose + 2);
     }
-  };
-})();
+    return open ? text.slice(open) : text;
+  }
+}
diff --git a/js/prefs.js b/js/prefs.js
index e545d121..27e810de 100644
--- a/js/prefs.js
+++ b/js/prefs.js
@@ -57,9 +57,9 @@ var prefs = new function Prefs() {
       end_with_newline: false,
       indent_conditional: true,
     },
-    'editor.lintDelay': 500,        // lint gutter marker update delay, ms
+    'editor.lintDelay': 300,        // lint gutter marker update delay, ms
     'editor.linter': 'csslint',     // 'csslint' or 'stylelint' or ''
-    'editor.lintReportDelay': 4500, // lint report update delay, ms
+    'editor.lintReportDelay': 500,  // lint report update delay, ms
     'editor.matchHighlight': 'token', // token = token/word under cursor even if nothing is selected
                                       // selection = only when something is selected
                                       // '' (empty string) = disabled
@@ -234,6 +234,7 @@ var prefs = new function Prefs() {
     // Unlike chrome.storage or messaging, HTML5 localStorage is synchronous and always ready,
     // so we'll mirror the prefs to avoid using the wrong defaults during the startup phase
     const importFromLocalStorage = () => {
+      forgetOutdatedDefaults(localStorage);
       for (const key in defaults) {
         const defaultValue = defaults[key];
         let value = localStorage[key];
@@ -323,6 +324,7 @@ var prefs = new function Prefs() {
   }
 
   function importFromSync(synced = {}) {
+    forgetOutdatedDefaults(synced);
     for (const key in defaults) {
       if (key in synced) {
         this.set(key, synced[key], {sync: false});
@@ -330,6 +332,12 @@ var prefs = new function Prefs() {
     }
   }
 
+  function forgetOutdatedDefaults(storage) {
+    // our linter runs as a worker so we can reduce the delay and forget the old default values
+    if (Number(storage['editor.lintDelay']) === 500) delete storage['editor.lintDelay'];
+    if (Number(storage['editor.lintReportDelay']) === 4500) delete storage['editor.lintReportDelay'];
+  }
+
   function defineReadonlyProperty(obj, key, value) {
     const copy = deepCopy(value);
     if (typeof copy === 'object') {
diff --git a/js/usercss.js b/js/usercss.js
index 8d18b16f..340136e1 100644
--- a/js/usercss.js
+++ b/js/usercss.js
@@ -1,4 +1,4 @@
-/* global loadScript mozParser semverCompare colorConverter styleCodeEmpty */
+/* global loadScript semverCompare colorConverter styleCodeEmpty */
 'use strict';
 
 // eslint-disable-next-line no-var
@@ -485,11 +485,17 @@ var usercss = (() => {
 
     const sVars = simpleVars(vars);
 
-    return Promise.resolve(builder.preprocess && builder.preprocess(sourceCode, sVars) || sourceCode)
+    return (
+      Promise.resolve(
+        builder.preprocess && builder.preprocess(sourceCode, sVars) ||
+        sourceCode)
       .then(mozStyle => invokeWorker({action: 'parse', code: mozStyle}))
-      .then(sections => (style.sections = sections))
-      .then(() => builder.postprocess && builder.postprocess(style.sections, sVars))
-      .then(() => style);
+      .then(({sections, errors}) => sections.length && sections || Promise.reject(errors))
+      .then(sections => {
+        style.sections = sections;
+        if (builder.postprocess) builder.postprocess(style.sections, sVars);
+        return style;
+      }));
   }
 
   function simpleVars(vars) {
@@ -568,7 +574,7 @@ var usercss = (() => {
 
   function invokeWorker(message) {
     if (!worker.queue) {
-      worker.instance = new Worker('/vendor-overwrites/csslint/csslint-worker.js');
+      worker.instance = new Worker('/vendor-overwrites/csslint/csslint-loader.js');
       worker.queue = [];
       worker.instance.onmessage = ({data}) => {
         worker.queue.shift().resolve(data.__ERROR__ ? Promise.reject(data.__ERROR__) : data);
diff --git a/vendor-overwrites/csslint/csslint-loader.js b/vendor-overwrites/csslint/csslint-loader.js
new file mode 100644
index 00000000..89788180
--- /dev/null
+++ b/vendor-overwrites/csslint/csslint-loader.js
@@ -0,0 +1,35 @@
+/* global parserlib CSSLint parseMozFormat */
+'use strict';
+
+self.importScripts('./parserlib.js');
+parserlib.css.Tokens[parserlib.css.Tokens.COMMENT].hide = false;
+
+self.onmessage = ({data: {action = 'run', code, config}}) => {
+
+  if (action === 'parse') {
+    if (!self.parseMozFormat) self.importScripts('/js/moz-parser.js');
+    self.postMessage(parseMozFormat(code));
+    return;
+  }
+  if (!self.CSSLint) self.importScripts('./csslint.js');
+
+  switch (action) {
+    case 'getAllRuleIds':
+      // the functions are non-tranferable and we need only an id
+      self.postMessage(CSSLint.getRules().map(rule => rule.id));
+      return;
+
+    case 'getAllRuleInfos':
+      // the functions are non-tranferable
+      self.postMessage(CSSLint.getRules().map(rule => JSON.parse(JSON.stringify(rule))));
+      return;
+
+    case 'run': {
+      const results = CSSLint.verify(code, config).messages
+        //.filter(m => !m.message.includes('/*[[') && !m.message.includes(']]*/'))
+        .map(m => Object.assign(m, {rule: {id: m.rule.id}}));
+      self.postMessage(results);
+      return;
+    }
+  }
+};
diff --git a/vendor-overwrites/csslint/csslint-worker.js b/vendor-overwrites/csslint/csslint-worker.js
deleted file mode 100644
index 61f72963..00000000
--- a/vendor-overwrites/csslint/csslint-worker.js
+++ /dev/null
@@ -1,11145 +0,0 @@
-/*!
-CSSLint v1.0.4
-Copyright (c) 2016 Nicole Sullivan and Nicholas C. Zakas. All rights reserved.
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the 'Software'), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
-
-*/
-var exports = exports || {};
-/*!
-Parser-Lib
-Copyright (c) 2009-2016 Nicholas C. Zakas. All rights reserved.
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
-*/
-/* Version v1.1.0, Build time: 6-December-2016 10:31:29 */
-var parserlib = (function () {
-var require;
-require=(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
-"use strict";
-
-/* exported Colors */
-
-var Colors = module.exports = {
-    __proto__       :null,
-    aliceblue       :"#f0f8ff",
-    antiquewhite    :"#faebd7",
-    aqua            :"#00ffff",
-    aquamarine      :"#7fffd4",
-    azure           :"#f0ffff",
-    beige           :"#f5f5dc",
-    bisque          :"#ffe4c4",
-    black           :"#000000",
-    blanchedalmond  :"#ffebcd",
-    blue            :"#0000ff",
-    blueviolet      :"#8a2be2",
-    brown           :"#a52a2a",
-    burlywood       :"#deb887",
-    cadetblue       :"#5f9ea0",
-    chartreuse      :"#7fff00",
-    chocolate       :"#d2691e",
-    coral           :"#ff7f50",
-    cornflowerblue  :"#6495ed",
-    cornsilk        :"#fff8dc",
-    crimson         :"#dc143c",
-    cyan            :"#00ffff",
-    darkblue        :"#00008b",
-    darkcyan        :"#008b8b",
-    darkgoldenrod   :"#b8860b",
-    darkgray        :"#a9a9a9",
-    darkgrey        :"#a9a9a9",
-    darkgreen       :"#006400",
-    darkkhaki       :"#bdb76b",
-    darkmagenta     :"#8b008b",
-    darkolivegreen  :"#556b2f",
-    darkorange      :"#ff8c00",
-    darkorchid      :"#9932cc",
-    darkred         :"#8b0000",
-    darksalmon      :"#e9967a",
-    darkseagreen    :"#8fbc8f",
-    darkslateblue   :"#483d8b",
-    darkslategray   :"#2f4f4f",
-    darkslategrey   :"#2f4f4f",
-    darkturquoise   :"#00ced1",
-    darkviolet      :"#9400d3",
-    deeppink        :"#ff1493",
-    deepskyblue     :"#00bfff",
-    dimgray         :"#696969",
-    dimgrey         :"#696969",
-    dodgerblue      :"#1e90ff",
-    firebrick       :"#b22222",
-    floralwhite     :"#fffaf0",
-    forestgreen     :"#228b22",
-    fuchsia         :"#ff00ff",
-    gainsboro       :"#dcdcdc",
-    ghostwhite      :"#f8f8ff",
-    gold            :"#ffd700",
-    goldenrod       :"#daa520",
-    gray            :"#808080",
-    grey            :"#808080",
-    green           :"#008000",
-    greenyellow     :"#adff2f",
-    honeydew        :"#f0fff0",
-    hotpink         :"#ff69b4",
-    indianred       :"#cd5c5c",
-    indigo          :"#4b0082",
-    ivory           :"#fffff0",
-    khaki           :"#f0e68c",
-    lavender        :"#e6e6fa",
-    lavenderblush   :"#fff0f5",
-    lawngreen       :"#7cfc00",
-    lemonchiffon    :"#fffacd",
-    lightblue       :"#add8e6",
-    lightcoral      :"#f08080",
-    lightcyan       :"#e0ffff",
-    lightgoldenrodyellow  :"#fafad2",
-    lightgray       :"#d3d3d3",
-    lightgrey       :"#d3d3d3",
-    lightgreen      :"#90ee90",
-    lightpink       :"#ffb6c1",
-    lightsalmon     :"#ffa07a",
-    lightseagreen   :"#20b2aa",
-    lightskyblue    :"#87cefa",
-    lightslategray  :"#778899",
-    lightslategrey  :"#778899",
-    lightsteelblue  :"#b0c4de",
-    lightyellow     :"#ffffe0",
-    lime            :"#00ff00",
-    limegreen       :"#32cd32",
-    linen           :"#faf0e6",
-    magenta         :"#ff00ff",
-    maroon          :"#800000",
-    mediumaquamarine:"#66cdaa",
-    mediumblue      :"#0000cd",
-    mediumorchid    :"#ba55d3",
-    mediumpurple    :"#9370db",
-    mediumseagreen  :"#3cb371",
-    mediumslateblue :"#7b68ee",
-    mediumspringgreen   :"#00fa9a",
-    mediumturquoise :"#48d1cc",
-    mediumvioletred :"#c71585",
-    midnightblue    :"#191970",
-    mintcream       :"#f5fffa",
-    mistyrose       :"#ffe4e1",
-    moccasin        :"#ffe4b5",
-    navajowhite     :"#ffdead",
-    navy            :"#000080",
-    oldlace         :"#fdf5e6",
-    olive           :"#808000",
-    olivedrab       :"#6b8e23",
-    orange          :"#ffa500",
-    orangered       :"#ff4500",
-    orchid          :"#da70d6",
-    palegoldenrod   :"#eee8aa",
-    palegreen       :"#98fb98",
-    paleturquoise   :"#afeeee",
-    palevioletred   :"#db7093",
-    papayawhip      :"#ffefd5",
-    peachpuff       :"#ffdab9",
-    peru            :"#cd853f",
-    pink            :"#ffc0cb",
-    plum            :"#dda0dd",
-    powderblue      :"#b0e0e6",
-    purple          :"#800080",
-    rebeccapurple   :"#663399",
-    red             :"#ff0000",
-    rosybrown       :"#bc8f8f",
-    royalblue       :"#4169e1",
-    saddlebrown     :"#8b4513",
-    salmon          :"#fa8072",
-    sandybrown      :"#f4a460",
-    seagreen        :"#2e8b57",
-    seashell        :"#fff5ee",
-    sienna          :"#a0522d",
-    silver          :"#c0c0c0",
-    skyblue         :"#87ceeb",
-    slateblue       :"#6a5acd",
-    slategray       :"#708090",
-    slategrey       :"#708090",
-    snow            :"#fffafa",
-    springgreen     :"#00ff7f",
-    steelblue       :"#4682b4",
-    tan             :"#d2b48c",
-    teal            :"#008080",
-    thistle         :"#d8bfd8",
-    tomato          :"#ff6347",
-    turquoise       :"#40e0d0",
-    violet          :"#ee82ee",
-    wheat           :"#f5deb3",
-    white           :"#ffffff",
-    whitesmoke      :"#f5f5f5",
-    yellow          :"#ffff00",
-    yellowgreen     :"#9acd32",
-    //'currentColor' color keyword https://www.w3.org/TR/css3-color/#currentcolor
-    currentColor        :"The value of the 'color' property.",
-    //CSS2 system colors https://www.w3.org/TR/css3-color/#css2-system
-    activeborder        :"Active window border.",
-    activecaption       :"Active window caption.",
-    appworkspace        :"Background color of multiple document interface.",
-    background          :"Desktop background.",
-    buttonface          :"The face background color for 3-D elements that appear 3-D due to one layer of surrounding border.",
-    buttonhighlight     :"The color of the border facing the light source for 3-D elements that appear 3-D due to one layer of surrounding border.",
-    buttonshadow        :"The color of the border away from the light source for 3-D elements that appear 3-D due to one layer of surrounding border.",
-    buttontext          :"Text on push buttons.",
-    captiontext         :"Text in caption, size box, and scrollbar arrow box.",
-    graytext            :"Grayed (disabled) text. This color is set to #000 if the current display driver does not support a solid gray color.",
-    greytext            :"Greyed (disabled) text. This color is set to #000 if the current display driver does not support a solid grey color.",
-    highlight           :"Item(s) selected in a control.",
-    highlighttext       :"Text of item(s) selected in a control.",
-    inactiveborder      :"Inactive window border.",
-    inactivecaption     :"Inactive window caption.",
-    inactivecaptiontext :"Color of text in an inactive caption.",
-    infobackground      :"Background color for tooltip controls.",
-    infotext            :"Text color for tooltip controls.",
-    menu                :"Menu background.",
-    menutext            :"Text in menus.",
-    scrollbar           :"Scroll bar gray area.",
-    threeddarkshadow    :"The color of the darker (generally outer) of the two borders away from the light source for 3-D elements that appear 3-D due to two concentric layers of surrounding border.",
-    threedface          :"The face background color for 3-D elements that appear 3-D due to two concentric layers of surrounding border.",
-    threedhighlight     :"The color of the lighter (generally outer) of the two borders facing the light source for 3-D elements that appear 3-D due to two concentric layers of surrounding border.",
-    threedlightshadow   :"The color of the darker (generally inner) of the two borders facing the light source for 3-D elements that appear 3-D due to two concentric layers of surrounding border.",
-    threedshadow        :"The color of the lighter (generally inner) of the two borders away from the light source for 3-D elements that appear 3-D due to two concentric layers of surrounding border.",
-    window              :"Window background.",
-    windowframe         :"Window frame.",
-    windowtext          :"Text in windows."
-};
-
-},{}],2:[function(require,module,exports){
-"use strict";
-
-module.exports = Combinator;
-
-var SyntaxUnit = require("../util/SyntaxUnit");
-
-var Parser = require("./Parser");
-
-/**
- * Represents a selector combinator (whitespace, +, >).
- * @namespace parserlib.css
- * @class Combinator
- * @extends parserlib.util.SyntaxUnit
- * @constructor
- * @param {String} text The text representation of the unit.
- * @param {int} line The line of text on which the unit resides.
- * @param {int} col The column of text on which the unit resides.
- */
-function Combinator(text, line, col) {
-
-    SyntaxUnit.call(this, text, line, col, Parser.COMBINATOR_TYPE);
-
-    /**
-     * The type of modifier.
-     * @type String
-     * @property type
-     */
-    this.type = "unknown";
-
-    //pretty simple
-    if (/^\s+$/.test(text)) {
-        this.type = "descendant";
-    } else if (text === ">") {
-        this.type = "child";
-    } else if (text === "+") {
-        this.type = "adjacent-sibling";
-    } else if (text === "~") {
-        this.type = "sibling";
-    }
-
-}
-
-Combinator.prototype = new SyntaxUnit();
-Combinator.prototype.constructor = Combinator;
-
-
-},{"../util/SyntaxUnit":26,"./Parser":6}],3:[function(require,module,exports){
-"use strict";
-
-module.exports = Matcher;
-
-var StringReader = require("../util/StringReader");
-var SyntaxError = require("../util/SyntaxError");
-
-/**
- * This class implements a combinator library for matcher functions.
- * The combinators are described at:
- * https://developer.mozilla.org/en-US/docs/Web/CSS/Value_definition_syntax#Component_value_combinators
- */
-function Matcher(matchFunc, toString) {
-    this.match = function(expression) {
-        // Save/restore marks to ensure that failed matches always restore
-        // the original location in the expression.
-        var result;
-        expression.mark();
-        result = matchFunc(expression);
-        if (result) {
-            expression.drop();
-        } else {
-            expression.restore();
-        }
-        return result;
-    };
-    this.toString = typeof toString === "function" ? toString : function() {
-        return toString;
-    };
-}
-
-/** Precedence table of combinators. */
-Matcher.prec = {
-    MOD:    5,
-    SEQ:    4,
-    ANDAND: 3,
-    OROR:   2,
-    ALT:    1
-};
-
-/** Simple recursive-descent grammar to build matchers from strings. */
-Matcher.parse = function(str) {
-    var reader, eat, expr, oror, andand, seq, mod, term, result;
-    reader = new StringReader(str);
-    eat = function(matcher) {
-        var result = reader.readMatch(matcher);
-        if (result === null) {
-            throw new SyntaxError(
-                "Expected "+matcher, reader.getLine(), reader.getCol());
-        }
-        return result;
-    };
-    expr = function() {
-        // expr = oror (" | " oror)*
-        var m = [ oror() ];
-        while (reader.readMatch(" | ") !== null) {
-            m.push(oror());
-        }
-        return m.length === 1 ? m[0] : Matcher.alt.apply(Matcher, m);
-    };
-    oror = function() {
-        // oror = andand ( " || " andand)*
-        var m = [ andand() ];
-        while (reader.readMatch(" || ") !== null) {
-            m.push(andand());
-        }
-        return m.length === 1 ? m[0] : Matcher.oror.apply(Matcher, m);
-    };
-    andand = function() {
-        // andand = seq ( " && " seq)*
-        var m = [ seq() ];
-        while (reader.readMatch(" && ") !== null) {
-            m.push(seq());
-        }
-        return m.length === 1 ? m[0] : Matcher.andand.apply(Matcher, m);
-    };
-    seq = function() {
-        // seq = mod ( " " mod)*
-        var m = [ mod() ];
-        while (reader.readMatch(/\s(?![&|\]])/y) !== null) {
-            m.push(mod());
-        }
-        return m.length === 1 ? m[0] : Matcher.seq.apply(Matcher, m);
-    };
-    mod = function() {
-        // mod = term ( "?" | "*" | "+" | "#" | "{<num>,<num>}" )?
-        var m = term();
-        if (reader.readMatch("?") !== null) {
-            return m.question();
-        } else if (reader.readMatch("*") !== null) {
-            return m.star();
-        } else if (reader.readMatch("+") !== null) {
-            return m.plus();
-        } else if (reader.readMatch("#") !== null) {
-            return m.hash();
-        } else if (reader.readMatch(/\{\s*/y) !== null) {
-            var min = eat(/\d+/y);
-            eat(/\s*,\s*/y);
-            var max = eat(/\d+/y);
-            eat(/\s*\}/y);
-            return m.braces(+min, +max);
-        }
-        return m;
-    };
-    term = function() {
-        // term = <nt> | literal | "[ " expression " ]"
-        if (reader.readMatch("[ ") !== null) {
-            var m = expr();
-            eat(" ]");
-            return m;
-        }
-        return Matcher.fromType(eat(/[^ ?*+#{]+/y));
-    };
-    result = expr();
-    if (!reader.eof()) {
-        throw new SyntaxError(
-            "Expected end of string", reader.getLine(), reader.getCol());
-    }
-    return result;
-};
-
-/**
- * Convert a string to a matcher (parsing simple alternations),
- * or do nothing if the argument is already a matcher.
- */
-Matcher.cast = function(m) {
-    if (m instanceof Matcher) {
-        return m;
-    }
-    return Matcher.parse(m);
-};
-
-/**
- * Create a matcher for a single type.
- */
-Matcher.fromType = function(type) {
-    // Late require of ValidationTypes to break a dependency cycle.
-    var ValidationTypes = require("./ValidationTypes");
-    return new Matcher(function(expression) {
-        return expression.hasNext() && ValidationTypes.isType(expression, type);
-    }, type);
-};
-
-/**
- * Create a matcher for one or more juxtaposed words, which all must
- * occur, in the given order.
- */
-Matcher.seq = function() {
-    var ms = Array.prototype.slice.call(arguments).map(Matcher.cast);
-    if (ms.length === 1) {
-        return ms[0];
-    }
-    return new Matcher(function(expression) {
-        var i, result = true;
-        for (i = 0; result && i < ms.length; i++) {
-            result = ms[i].match(expression);
-        }
-        return result;
-    }, function(prec) {
-        var p = Matcher.prec.SEQ;
-        var s = ms.map(function(m) {
-            return m.toString(p);
-        }).join(" ");
-        if (prec > p) {
-            s = "[ " + s + " ]";
-        }
-        return s;
-    });
-};
-
-/**
- * Create a matcher for one or more alternatives, where exactly one
- * must occur.
- */
-Matcher.alt = function() {
-    var ms = Array.prototype.slice.call(arguments).map(Matcher.cast);
-    if (ms.length === 1) {
-        return ms[0];
-    }
-    return new Matcher(function(expression) {
-        var i, result = false;
-        for (i = 0; !result && i < ms.length; i++) {
-            result = ms[i].match(expression);
-        }
-        return result;
-    }, function(prec) {
-        var p = Matcher.prec.ALT;
-        var s = ms.map(function(m) {
-            return m.toString(p);
-        }).join(" | ");
-        if (prec > p) {
-            s = "[ " + s + " ]";
-        }
-        return s;
-    });
-};
-
-/**
- * Create a matcher for two or more options.  This implements the
- * double bar (||) and double ampersand (&&) operators, as well as
- * variants of && where some of the alternatives are optional.
- * This will backtrack through even successful matches to try to
- * maximize the number of items matched.
- */
-Matcher.many = function(required) {
-    var ms = Array.prototype.slice.call(arguments, 1).reduce(function(acc, v) {
-        if (v.expand) {
-            // Insert all of the options for the given complex rule as
-            // individual options.
-            var ValidationTypes = require("./ValidationTypes");
-            acc.push.apply(acc, ValidationTypes.complex[v.expand].options);
-        } else {
-            acc.push(Matcher.cast(v));
-        }
-        return acc;
-    }, []);
-
-    if (required === true) {
-        required = ms.map(function() {
-            return true;
-        });
-    }
-
-    var result = new Matcher(function(expression) {
-        var seen = [], max = 0, pass = 0;
-        var success = function(matchCount) {
-            if (pass === 0) {
-                max = Math.max(matchCount, max);
-                return matchCount === ms.length;
-            } else {
-                return matchCount === max;
-            }
-        };
-        var tryMatch = function(matchCount) {
-            for (var i = 0; i < ms.length; i++) {
-                if (seen[i]) {
-                    continue;
-                }
-                expression.mark();
-                if (ms[i].match(expression)) {
-                    seen[i] = true;
-                    // Increase matchCount iff this was a required element
-                    // (or if all the elements are optional)
-                    if (tryMatch(matchCount + ((required === false || required[i]) ? 1 : 0))) {
-                        expression.drop();
-                        return true;
-                    }
-                    // Backtrack: try *not* matching using this rule, and
-                    // let's see if it leads to a better overall match.
-                    expression.restore();
-                    seen[i] = false;
-                } else {
-                    expression.drop();
-                }
-            }
-            return success(matchCount);
-        };
-        if (!tryMatch(0)) {
-            // Couldn't get a complete match, retrace our steps to make the
-            // match with the maximum # of required elements.
-            pass++;
-            tryMatch(0);
-        }
-
-        if (required === false) {
-            return max > 0;
-        }
-        // Use finer-grained specification of which matchers are required.
-        for (var i = 0; i < ms.length; i++) {
-            if (required[i] && !seen[i]) {
-                return false;
-            }
-        }
-        return true;
-    }, function(prec) {
-        var p = required === false ? Matcher.prec.OROR : Matcher.prec.ANDAND;
-        var s = ms.map(function(m, i) {
-            if (required !== false && !required[i]) {
-                return m.toString(Matcher.prec.MOD) + "?";
-            }
-            return m.toString(p);
-        }).join(required === false ? " || " : " && ");
-        if (prec > p) {
-            s = "[ " + s + " ]";
-        }
-        return s;
-    });
-    result.options = ms;
-    return result;
-};
-
-/**
- * Create a matcher for two or more options, where all options are
- * mandatory but they may appear in any order.
- */
-Matcher.andand = function() {
-    var args = Array.prototype.slice.call(arguments);
-    args.unshift(true);
-    return Matcher.many.apply(Matcher, args);
-};
-
-/**
- * Create a matcher for two or more options, where options are
- * optional and may appear in any order, but at least one must be
- * present.
- */
-Matcher.oror = function() {
-    var args = Array.prototype.slice.call(arguments);
-    args.unshift(false);
-    return Matcher.many.apply(Matcher, args);
-};
-
-/** Instance methods on Matchers. */
-Matcher.prototype = {
-    constructor: Matcher,
-    // These are expected to be overridden in every instance.
-    match: function() { throw new Error("unimplemented"); },
-    toString: function() { throw new Error("unimplemented"); },
-    // This returns a standalone function to do the matching.
-    func: function() { return this.match.bind(this); },
-    // Basic combinators
-    then: function(m) { return Matcher.seq(this, m); },
-    or: function(m) { return Matcher.alt(this, m); },
-    andand: function(m) { return Matcher.many(true, this, m); },
-    oror: function(m) { return Matcher.many(false, this, m); },
-    // Component value multipliers
-    star: function() { return this.braces(0, Infinity, "*"); },
-    plus: function() { return this.braces(1, Infinity, "+"); },
-    question: function() { return this.braces(0, 1, "?"); },
-    hash: function() {
-        return this.braces(1, Infinity, "#", Matcher.cast(","));
-    },
-    braces: function(min, max, marker, optSep) {
-        var m1 = this, m2 = optSep ? optSep.then(this) : this;
-        if (!marker) {
-            marker = "{" + min + "," + max + "}";
-        }
-        return new Matcher(function(expression) {
-            var result = true, i;
-            for (i = 0; i < max; i++) {
-                if (i > 0 && optSep) {
-                    result = m2.match(expression);
-                } else {
-                    result = m1.match(expression);
-                }
-                if (!result) {
-                    break;
-                }
-            }
-            return i >= min;
-        }, function() {
-            return m1.toString(Matcher.prec.MOD) + marker;
-        });
-    }
-};
-
-},{"../util/StringReader":24,"../util/SyntaxError":25,"./ValidationTypes":21}],4:[function(require,module,exports){
-"use strict";
-
-module.exports = MediaFeature;
-
-var SyntaxUnit = require("../util/SyntaxUnit");
-
-var Parser = require("./Parser");
-
-/**
- * Represents a media feature, such as max-width:500.
- * @namespace parserlib.css
- * @class MediaFeature
- * @extends parserlib.util.SyntaxUnit
- * @constructor
- * @param {SyntaxUnit} name The name of the feature.
- * @param {SyntaxUnit} value The value of the feature or null if none.
- */
-function MediaFeature(name, value) {
-
-    SyntaxUnit.call(this, "(" + name + (value !== null ? ":" + value : "") + ")", name.startLine, name.startCol, Parser.MEDIA_FEATURE_TYPE);
-
-    /**
-     * The name of the media feature
-     * @type String
-     * @property name
-     */
-    this.name = name;
-
-    /**
-     * The value for the feature or null if there is none.
-     * @type SyntaxUnit
-     * @property value
-     */
-    this.value = value;
-}
-
-MediaFeature.prototype = new SyntaxUnit();
-MediaFeature.prototype.constructor = MediaFeature;
-
-
-},{"../util/SyntaxUnit":26,"./Parser":6}],5:[function(require,module,exports){
-"use strict";
-
-module.exports = MediaQuery;
-
-var SyntaxUnit = require("../util/SyntaxUnit");
-
-var Parser = require("./Parser");
-
-/**
- * Represents an individual media query.
- * @namespace parserlib.css
- * @class MediaQuery
- * @extends parserlib.util.SyntaxUnit
- * @constructor
- * @param {String} modifier The modifier "not" or "only" (or null).
- * @param {String} mediaType The type of media (i.e., "print").
- * @param {Array} parts Array of selectors parts making up this selector.
- * @param {int} line The line of text on which the unit resides.
- * @param {int} col The column of text on which the unit resides.
- */
-function MediaQuery(modifier, mediaType, features, line, col) {
-
-    SyntaxUnit.call(this, (modifier ? modifier + " ": "") + (mediaType ? mediaType : "") + (mediaType && features.length > 0 ? " and " : "") + features.join(" and "), line, col, Parser.MEDIA_QUERY_TYPE);
-
-    /**
-     * The media modifier ("not" or "only")
-     * @type String
-     * @property modifier
-     */
-    this.modifier = modifier;
-
-    /**
-     * The mediaType (i.e., "print")
-     * @type String
-     * @property mediaType
-     */
-    this.mediaType = mediaType;
-
-    /**
-     * The parts that make up the selector.
-     * @type Array
-     * @property features
-     */
-    this.features = features;
-
-}
-
-MediaQuery.prototype = new SyntaxUnit();
-MediaQuery.prototype.constructor = MediaQuery;
-
-
-},{"../util/SyntaxUnit":26,"./Parser":6}],6:[function(require,module,exports){
-"use strict";
-
-module.exports = Parser;
-
-var EventTarget = require("../util/EventTarget");
-var SyntaxError = require("../util/SyntaxError");
-var SyntaxUnit = require("../util/SyntaxUnit");
-
-var Combinator = require("./Combinator");
-var MediaFeature = require("./MediaFeature");
-var MediaQuery = require("./MediaQuery");
-var PropertyName = require("./PropertyName");
-var PropertyValue = require("./PropertyValue");
-var PropertyValuePart = require("./PropertyValuePart");
-var Selector = require("./Selector");
-var SelectorPart = require("./SelectorPart");
-var SelectorSubPart = require("./SelectorSubPart");
-var TokenStream = require("./TokenStream");
-var Tokens = require("./Tokens");
-var Validation = require("./Validation");
-
-/**
- * A CSS3 parser.
- * @namespace parserlib.css
- * @class Parser
- * @constructor
- * @param {Object} options (Optional) Various options for the parser:
- *      starHack (true|false) to allow IE6 star hack as valid,
- *      underscoreHack (true|false) to interpret leading underscores
- *      as IE6-7 targeting for known properties, ieFilters (true|false)
- *      to indicate that IE < 8 filters should be accepted and not throw
- *      syntax errors.
- */
-function Parser(options) {
-
-    //inherit event functionality
-    EventTarget.call(this);
-
-
-    this.options = options || {};
-
-    this._tokenStream = null;
-}
-
-//Static constants
-Parser.DEFAULT_TYPE = 0;
-Parser.COMBINATOR_TYPE = 1;
-Parser.MEDIA_FEATURE_TYPE = 2;
-Parser.MEDIA_QUERY_TYPE = 3;
-Parser.PROPERTY_NAME_TYPE = 4;
-Parser.PROPERTY_VALUE_TYPE = 5;
-Parser.PROPERTY_VALUE_PART_TYPE = 6;
-Parser.SELECTOR_TYPE = 7;
-Parser.SELECTOR_PART_TYPE = 8;
-Parser.SELECTOR_SUB_PART_TYPE = 9;
-
-Parser.prototype = function() {
-
-    var proto = new EventTarget(),  //new prototype
-        prop,
-        additions =  {
-            __proto__: null,
-
-            //restore constructor
-            constructor: Parser,
-
-            //instance constants - yuck
-            DEFAULT_TYPE : 0,
-            COMBINATOR_TYPE : 1,
-            MEDIA_FEATURE_TYPE : 2,
-            MEDIA_QUERY_TYPE : 3,
-            PROPERTY_NAME_TYPE : 4,
-            PROPERTY_VALUE_TYPE : 5,
-            PROPERTY_VALUE_PART_TYPE : 6,
-            SELECTOR_TYPE : 7,
-            SELECTOR_PART_TYPE : 8,
-            SELECTOR_SUB_PART_TYPE : 9,
-
-            //-----------------------------------------------------------------
-            // Grammar
-            //-----------------------------------------------------------------
-
-            _stylesheet: function() {
-
-                /*
-                 * stylesheet
-                 *  : [ CHARSET_SYM S* STRING S* ';' ]?
-                 *    [S|CDO|CDC]* [ import [S|CDO|CDC]* ]*
-                 *    [ namespace [S|CDO|CDC]* ]*
-                 *    [ [ ruleset | media | page | font_face | keyframes_rule | supports_rule ] [S|CDO|CDC]* ]*
-                 *  ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    count,
-                    token,
-                    tt;
-
-                this.fire("startstylesheet");
-
-                //try to read character set
-                this._charset();
-
-                this._skipCruft();
-
-                //try to read imports - may be more than one
-                while (tokenStream.peek() === Tokens.IMPORT_SYM) {
-                    this._import();
-                    this._skipCruft();
-                }
-
-                //try to read namespaces - may be more than one
-                while (tokenStream.peek() === Tokens.NAMESPACE_SYM) {
-                    this._namespace();
-                    this._skipCruft();
-                }
-
-                //get the next token
-                tt = tokenStream.peek();
-
-                //try to read the rest
-                while (tt > Tokens.EOF) {
-
-                    try {
-
-                        switch (tt) {
-                            case Tokens.MEDIA_SYM:
-                                this._media();
-                                this._skipCruft();
-                                break;
-                            case Tokens.PAGE_SYM:
-                                this._page();
-                                this._skipCruft();
-                                break;
-                            case Tokens.FONT_FACE_SYM:
-                                this._font_face();
-                                this._skipCruft();
-                                break;
-                            case Tokens.KEYFRAMES_SYM:
-                                this._keyframes();
-                                this._skipCruft();
-                                break;
-                            case Tokens.VIEWPORT_SYM:
-                                this._viewport();
-                                this._skipCruft();
-                                break;
-                            case Tokens.DOCUMENT_SYM:
-                                this._document();
-                                this._skipCruft();
-                                break;
-                            case Tokens.SUPPORTS_SYM:
-                                this._supports();
-                                this._skipCruft();
-                                break;
-                            case Tokens.UNKNOWN_SYM:  //unknown @ rule
-                                tokenStream.get();
-                                if (!this.options.strict) {
-
-                                    //fire error event
-                                    this.fire({
-                                        type:       "error",
-                                        error:      null,
-                                        message:    "Unknown @ rule: " + tokenStream.LT(0).value + ".",
-                                        line:       tokenStream.LT(0).startLine,
-                                        col:        tokenStream.LT(0).startCol
-                                    });
-
-                                    //skip braces
-                                    count=0;
-                                    while (tokenStream.advance([Tokens.LBRACE, Tokens.RBRACE]) === Tokens.LBRACE) {
-                                        count++;    //keep track of nesting depth
-                                    }
-
-                                    while (count) {
-                                        tokenStream.advance([Tokens.RBRACE]);
-                                        count--;
-                                    }
-
-                                } else {
-                                    //not a syntax error, rethrow it
-                                    throw new SyntaxError("Unknown @ rule.", tokenStream.LT(0).startLine, tokenStream.LT(0).startCol);
-                                }
-                                break;
-                            case Tokens.S:
-                                this._readWhitespace();
-                                break;
-                            default:
-                                if (!this._ruleset()) {
-
-                                    //error handling for known issues
-                                    switch (tt) {
-                                        case Tokens.CHARSET_SYM:
-                                            token = tokenStream.LT(1);
-                                            this._charset(false);
-                                            throw new SyntaxError("@charset not allowed here.", token.startLine, token.startCol);
-                                        case Tokens.IMPORT_SYM:
-                                            token = tokenStream.LT(1);
-                                            this._import(false);
-                                            throw new SyntaxError("@import not allowed here.", token.startLine, token.startCol);
-                                        case Tokens.NAMESPACE_SYM:
-                                            token = tokenStream.LT(1);
-                                            this._namespace(false);
-                                            throw new SyntaxError("@namespace not allowed here.", token.startLine, token.startCol);
-                                        default:
-                                            tokenStream.get();  //get the last token
-                                            this._unexpectedToken(tokenStream.token());
-                                    }
-
-                                }
-                        }
-                    } catch (ex) {
-                        if (ex instanceof SyntaxError && !this.options.strict) {
-                            this.fire({
-                                type:       "error",
-                                error:      ex,
-                                message:    ex.message,
-                                line:       ex.line,
-                                col:        ex.col
-                            });
-                        } else {
-                            throw ex;
-                        }
-                    }
-
-                    tt = tokenStream.peek();
-                }
-
-                if (tt !== Tokens.EOF) {
-                    this._unexpectedToken(tokenStream.token());
-                }
-
-                this.fire("endstylesheet");
-            },
-
-            _charset: function(emit) {
-                var tokenStream = this._tokenStream,
-                    charset,
-                    token,
-                    line,
-                    col;
-
-                if (tokenStream.match(Tokens.CHARSET_SYM)) {
-                    line = tokenStream.token().startLine;
-                    col = tokenStream.token().startCol;
-
-                    this._readWhitespace();
-                    tokenStream.mustMatch(Tokens.STRING);
-
-                    token = tokenStream.token();
-                    charset = token.value;
-
-                    this._readWhitespace();
-                    tokenStream.mustMatch(Tokens.SEMICOLON);
-
-                    if (emit !== false) {
-                        this.fire({
-                            type:   "charset",
-                            charset:charset,
-                            line:   line,
-                            col:    col
-                        });
-                    }
-                }
-            },
-
-            _import: function(emit) {
-                /*
-                 * import
-                 *   : IMPORT_SYM S*
-                 *    [STRING|URI] S* media_query_list? ';' S*
-                 */
-
-                var tokenStream = this._tokenStream,
-                    uri,
-                    importToken,
-                    mediaList   = [];
-
-                //read import symbol
-                tokenStream.mustMatch(Tokens.IMPORT_SYM);
-                importToken = tokenStream.token();
-                this._readWhitespace();
-
-                tokenStream.mustMatch([Tokens.STRING, Tokens.URI]);
-
-                //grab the URI value
-                uri = tokenStream.token().value.replace(/^(?:url\()?["']?([^"']+?)["']?\)?$/, "$1");
-
-                this._readWhitespace();
-
-                mediaList = this._media_query_list();
-
-                //must end with a semicolon
-                tokenStream.mustMatch(Tokens.SEMICOLON);
-                this._readWhitespace();
-
-                if (emit !== false) {
-                    this.fire({
-                        type:   "import",
-                        uri:    uri,
-                        media:  mediaList,
-                        line:   importToken.startLine,
-                        col:    importToken.startCol
-                    });
-                }
-
-            },
-
-            _namespace: function(emit) {
-                /*
-                 * namespace
-                 *   : NAMESPACE_SYM S* [namespace_prefix S*]? [STRING|URI] S* ';' S*
-                 */
-
-                var tokenStream = this._tokenStream,
-                    line,
-                    col,
-                    prefix,
-                    uri;
-
-                //read import symbol
-                tokenStream.mustMatch(Tokens.NAMESPACE_SYM);
-                line = tokenStream.token().startLine;
-                col = tokenStream.token().startCol;
-                this._readWhitespace();
-
-                //it's a namespace prefix - no _namespace_prefix() method because it's just an IDENT
-                if (tokenStream.match(Tokens.IDENT)) {
-                    prefix = tokenStream.token().value;
-                    this._readWhitespace();
-                }
-
-                tokenStream.mustMatch([Tokens.STRING, Tokens.URI]);
-                /*if (!tokenStream.match(Tokens.STRING)){
-                    tokenStream.mustMatch(Tokens.URI);
-                }*/
-
-                //grab the URI value
-                uri = tokenStream.token().value.replace(/(?:url\()?["']([^"']+)["']\)?/, "$1");
-
-                this._readWhitespace();
-
-                //must end with a semicolon
-                tokenStream.mustMatch(Tokens.SEMICOLON);
-                this._readWhitespace();
-
-                if (emit !== false) {
-                    this.fire({
-                        type:   "namespace",
-                        prefix: prefix,
-                        uri:    uri,
-                        line:   line,
-                        col:    col
-                    });
-                }
-
-            },
-
-            _supports: function(emit) {
-                /*
-                 * supports_rule
-                 *  : SUPPORTS_SYM S* supports_condition S* group_rule_body
-                 *  ;
-                 */
-                var tokenStream = this._tokenStream,
-                    line,
-                    col;
-
-                if (tokenStream.match(Tokens.SUPPORTS_SYM)) {
-                    line = tokenStream.token().startLine;
-                    col = tokenStream.token().startCol;
-
-                    this._readWhitespace();
-                    this._supports_condition();
-                    this._readWhitespace();
-
-                    tokenStream.mustMatch(Tokens.LBRACE);
-                    this._readWhitespace();
-
-                    if (emit !== false) {
-                        this.fire({
-                            type:   "startsupports",
-                            line:   line,
-                            col:    col
-                        });
-                    }
-
-                    var error;
-
-                    while (true) {
-                        if (!this._ruleset()) {
-                            var token = tokenStream.LT(1);
-                            if (token.type === tokenStream._tokenData.MEDIA_SYM) {
-                                this._media();
-                                error = new SyntaxError("@media not allowed here.", token.startLine, token.startCol);
-                            }
-                            break;
-                        }
-                    }
-
-                    tokenStream.mustMatch(Tokens.RBRACE);
-                    this._readWhitespace();
-
-                    this.fire({
-                        type:   "endsupports",
-                        line:   line,
-                        col:    col
-                    });
-                    if (error) {
-                        throw error;
-                    }
-                }
-            },
-
-            _supports_condition: function() {
-                /*
-                 * supports_condition
-                 *  : supports_negation | supports_conjunction | supports_disjunction |
-                 *    supports_condition_in_parens
-                 *  ;
-                 */
-                var tokenStream = this._tokenStream,
-                    ident;
-
-                if (tokenStream.match(Tokens.IDENT)) {
-                    ident = tokenStream.token().value.toLowerCase();
-
-                    if (ident === "not") {
-                        tokenStream.mustMatch(Tokens.S);
-                        this._supports_condition_in_parens();
-                    } else {
-                        tokenStream.unget();
-                    }
-                } else {
-                    this._supports_condition_in_parens();
-                    this._readWhitespace();
-
-                    while (tokenStream.peek() === Tokens.IDENT) {
-                        ident = tokenStream.LT(1).value.toLowerCase();
-                        if (ident === "and" || ident === "or") {
-                            tokenStream.mustMatch(Tokens.IDENT);
-                            this._readWhitespace();
-                            this._supports_condition_in_parens();
-                            this._readWhitespace();
-                        }
-                    }
-                }
-            },
-
-            _supports_condition_in_parens: function() {
-                /*
-                 * supports_condition_in_parens
-                 *  : ( '(' S* supports_condition S* ')' ) | supports_declaration_condition |
-                 *    general_enclosed
-                 *  ;
-                 */
-                var tokenStream = this._tokenStream,
-                    ident;
-
-                if (tokenStream.match(Tokens.LPAREN)) {
-                    this._readWhitespace();
-                    if (tokenStream.match(Tokens.IDENT)) {
-                        // look ahead for not keyword, if not given, continue with declaration condition.
-                        ident = tokenStream.token().value.toLowerCase();
-                        if (ident === "not") {
-                            this._readWhitespace();
-                            this._supports_condition();
-                            this._readWhitespace();
-                            tokenStream.mustMatch(Tokens.RPAREN);
-                        } else {
-                            tokenStream.unget();
-                            this._supports_declaration_condition(false);
-                        }
-                    } else {
-                        this._supports_condition();
-                        this._readWhitespace();
-                        tokenStream.mustMatch(Tokens.RPAREN);
-                    }
-                } else {
-                    this._supports_declaration_condition();
-                }
-            },
-
-            _supports_declaration_condition: function(requireStartParen) {
-                /*
-                 * supports_declaration_condition
-                 *  : '(' S* declaration ')'
-                 *  ;
-                 */
-                var tokenStream = this._tokenStream;
-
-                if (requireStartParen !== false) {
-                    tokenStream.mustMatch(Tokens.LPAREN);
-                }
-                this._readWhitespace();
-                this._declaration();
-                tokenStream.mustMatch(Tokens.RPAREN);
-            },
-
-            _media: function() {
-                /*
-                 * media
-                 *   : MEDIA_SYM S* media_query_list S* '{' S* ruleset* '}' S*
-                 *   ;
-                 */
-                var tokenStream     = this._tokenStream,
-                    line,
-                    col,
-                    mediaList;//       = [];
-
-                //look for @media
-                tokenStream.mustMatch(Tokens.MEDIA_SYM);
-                line = tokenStream.token().startLine;
-                col = tokenStream.token().startCol;
-
-                this._readWhitespace();
-
-                mediaList = this._media_query_list();
-
-                tokenStream.mustMatch(Tokens.LBRACE);
-                this._readWhitespace();
-
-                this.fire({
-                    type:   "startmedia",
-                    media:  mediaList,
-                    line:   line,
-                    col:    col
-                });
-
-                while (true) {
-                    if (tokenStream.peek() === Tokens.PAGE_SYM) {
-                        this._page();
-                    } else if (tokenStream.peek() === Tokens.FONT_FACE_SYM) {
-                        this._font_face();
-                    } else if (tokenStream.peek() === Tokens.VIEWPORT_SYM) {
-                        this._viewport();
-                    } else if (tokenStream.peek() === Tokens.DOCUMENT_SYM) {
-                        this._document();
-                    } else if (tokenStream.peek() === Tokens.SUPPORTS_SYM) {
-                        this._supports();
-                    } else if (tokenStream.peek() === Tokens.MEDIA_SYM) {
-                        this._media();
-                    } else if (!this._ruleset()) {
-                        break;
-                    }
-                }
-
-                tokenStream.mustMatch(Tokens.RBRACE);
-                this._readWhitespace();
-
-                this.fire({
-                    type:   "endmedia",
-                    media:  mediaList,
-                    line:   line,
-                    col:    col
-                });
-            },
-
-
-            //CSS3 Media Queries
-            _media_query_list: function() {
-                /*
-                 * media_query_list
-                 *   : S* [media_query [ ',' S* media_query ]* ]?
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream,
-                    mediaList   = [];
-
-
-                this._readWhitespace();
-
-                if (tokenStream.peek() === Tokens.IDENT || tokenStream.peek() === Tokens.LPAREN) {
-                    mediaList.push(this._media_query());
-                }
-
-                while (tokenStream.match(Tokens.COMMA)) {
-                    this._readWhitespace();
-                    mediaList.push(this._media_query());
-                }
-
-                return mediaList;
-            },
-
-            /*
-             * Note: "expression" in the grammar maps to the _media_expression
-             * method.
-
-             */
-            _media_query: function() {
-                /*
-                 * media_query
-                 *   : [ONLY | NOT]? S* media_type S* [ AND S* expression ]*
-                 *   | expression [ AND S* expression ]*
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream,
-                    type        = null,
-                    ident       = null,
-                    token       = null,
-                    expressions = [];
-
-                if (tokenStream.match(Tokens.IDENT)) {
-                    ident = tokenStream.token().value.toLowerCase();
-
-                    //since there's no custom tokens for these, need to manually check
-                    if (ident !== "only" && ident !== "not") {
-                        tokenStream.unget();
-                        ident = null;
-                    } else {
-                        token = tokenStream.token();
-                    }
-                }
-
-                this._readWhitespace();
-
-                if (tokenStream.peek() === Tokens.IDENT) {
-                    type = this._media_type();
-                    if (token === null) {
-                        token = tokenStream.token();
-                    }
-                } else if (tokenStream.peek() === Tokens.LPAREN) {
-                    if (token === null) {
-                        token = tokenStream.LT(1);
-                    }
-                    expressions.push(this._media_expression());
-                }
-
-                if (type === null && expressions.length === 0) {
-                    return null;
-                } else {
-                    this._readWhitespace();
-                    while (tokenStream.match(Tokens.IDENT)) {
-                        if (tokenStream.token().value.toLowerCase() !== "and") {
-                            this._unexpectedToken(tokenStream.token());
-                        }
-
-                        this._readWhitespace();
-                        expressions.push(this._media_expression());
-                    }
-                }
-
-                return new MediaQuery(ident, type, expressions, token.startLine, token.startCol);
-            },
-
-            //CSS3 Media Queries
-            _media_type: function() {
-                /*
-                 * media_type
-                 *   : IDENT
-                 *   ;
-                 */
-                return this._media_feature();
-            },
-
-            /**
-             * Note: in CSS3 Media Queries, this is called "expression".
-             * Renamed here to avoid conflict with CSS3 Selectors
-             * definition of "expression". Also note that "expr" in the
-             * grammar now maps to "expression" from CSS3 selectors.
-             * @method _media_expression
-             * @private
-             */
-            _media_expression: function() {
-                /*
-                 * expression
-                 *  : '(' S* media_feature S* [ ':' S* expr ]? ')' S*
-                 *  ;
-                 */
-                var tokenStream = this._tokenStream,
-                    feature     = null,
-                    token,
-                    expression  = null;
-
-                tokenStream.mustMatch(Tokens.LPAREN);
-
-                feature = this._media_feature();
-                this._readWhitespace();
-
-                if (tokenStream.match(Tokens.COLON)) {
-                    this._readWhitespace();
-                    token = tokenStream.LT(1);
-                    expression = this._expression();
-                }
-
-                tokenStream.mustMatch(Tokens.RPAREN);
-                this._readWhitespace();
-
-                return new MediaFeature(feature, expression ? new SyntaxUnit(expression, token.startLine, token.startCol) : null);
-            },
-
-            //CSS3 Media Queries
-            _media_feature: function() {
-                /*
-                 * media_feature
-                 *   : IDENT
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream;
-
-                this._readWhitespace();
-
-                tokenStream.mustMatch(Tokens.IDENT);
-
-                return SyntaxUnit.fromToken(tokenStream.token());
-            },
-
-            //CSS3 Paged Media
-            _page: function() {
-                /*
-                 * page:
-                 *    PAGE_SYM S* IDENT? pseudo_page? S*
-                 *    '{' S* [ declaration | margin ]? [ ';' S* [ declaration | margin ]? ]* '}' S*
-                 *    ;
-                 */
-                var tokenStream = this._tokenStream,
-                    line,
-                    col,
-                    identifier  = null,
-                    pseudoPage  = null;
-
-                //look for @page
-                tokenStream.mustMatch(Tokens.PAGE_SYM);
-                line = tokenStream.token().startLine;
-                col = tokenStream.token().startCol;
-
-                this._readWhitespace();
-
-                if (tokenStream.match(Tokens.IDENT)) {
-                    identifier = tokenStream.token().value;
-
-                    //The value 'auto' may not be used as a page name and MUST be treated as a syntax error.
-                    if (identifier.toLowerCase() === "auto") {
-                        this._unexpectedToken(tokenStream.token());
-                    }
-                }
-
-                //see if there's a colon upcoming
-                if (tokenStream.peek() === Tokens.COLON) {
-                    pseudoPage = this._pseudo_page();
-                }
-
-                this._readWhitespace();
-
-                this.fire({
-                    type:   "startpage",
-                    id:     identifier,
-                    pseudo: pseudoPage,
-                    line:   line,
-                    col:    col
-                });
-
-                this._readDeclarations(true, true);
-
-                this.fire({
-                    type:   "endpage",
-                    id:     identifier,
-                    pseudo: pseudoPage,
-                    line:   line,
-                    col:    col
-                });
-
-            },
-
-            //CSS3 Paged Media
-            _margin: function() {
-                /*
-                 * margin :
-                 *    margin_sym S* '{' declaration [ ';' S* declaration? ]* '}' S*
-                 *    ;
-                 */
-                var tokenStream = this._tokenStream,
-                    line,
-                    col,
-                    marginSym   = this._margin_sym();
-
-                if (marginSym) {
-                    line = tokenStream.token().startLine;
-                    col = tokenStream.token().startCol;
-
-                    this.fire({
-                        type: "startpagemargin",
-                        margin: marginSym,
-                        line:   line,
-                        col:    col
-                    });
-
-                    this._readDeclarations(true);
-
-                    this.fire({
-                        type: "endpagemargin",
-                        margin: marginSym,
-                        line:   line,
-                        col:    col
-                    });
-                    return true;
-                } else {
-                    return false;
-                }
-            },
-
-            //CSS3 Paged Media
-            _margin_sym: function() {
-
-                /*
-                 * margin_sym :
-                 *    TOPLEFTCORNER_SYM |
-                 *    TOPLEFT_SYM |
-                 *    TOPCENTER_SYM |
-                 *    TOPRIGHT_SYM |
-                 *    TOPRIGHTCORNER_SYM |
-                 *    BOTTOMLEFTCORNER_SYM |
-                 *    BOTTOMLEFT_SYM |
-                 *    BOTTOMCENTER_SYM |
-                 *    BOTTOMRIGHT_SYM |
-                 *    BOTTOMRIGHTCORNER_SYM |
-                 *    LEFTTOP_SYM |
-                 *    LEFTMIDDLE_SYM |
-                 *    LEFTBOTTOM_SYM |
-                 *    RIGHTTOP_SYM |
-                 *    RIGHTMIDDLE_SYM |
-                 *    RIGHTBOTTOM_SYM
-                 *    ;
-                 */
-
-                var tokenStream = this._tokenStream;
-
-                if (tokenStream.match([Tokens.TOPLEFTCORNER_SYM, Tokens.TOPLEFT_SYM,
-                        Tokens.TOPCENTER_SYM, Tokens.TOPRIGHT_SYM, Tokens.TOPRIGHTCORNER_SYM,
-                        Tokens.BOTTOMLEFTCORNER_SYM, Tokens.BOTTOMLEFT_SYM,
-                        Tokens.BOTTOMCENTER_SYM, Tokens.BOTTOMRIGHT_SYM,
-                        Tokens.BOTTOMRIGHTCORNER_SYM, Tokens.LEFTTOP_SYM,
-                        Tokens.LEFTMIDDLE_SYM, Tokens.LEFTBOTTOM_SYM, Tokens.RIGHTTOP_SYM,
-                        Tokens.RIGHTMIDDLE_SYM, Tokens.RIGHTBOTTOM_SYM])) {
-                    return SyntaxUnit.fromToken(tokenStream.token());
-                } else {
-                    return null;
-                }
-
-            },
-
-            _pseudo_page: function() {
-                /*
-                 * pseudo_page
-                 *   : ':' IDENT
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream;
-
-                tokenStream.mustMatch(Tokens.COLON);
-                tokenStream.mustMatch(Tokens.IDENT);
-
-                //TODO: CSS3 Paged Media says only "left", "center", and "right" are allowed
-
-                return tokenStream.token().value;
-            },
-
-            _font_face: function() {
-                /*
-                 * font_face
-                 *   : FONT_FACE_SYM S*
-                 *     '{' S* declaration [ ';' S* declaration ]* '}' S*
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream,
-                    line,
-                    col;
-
-                //look for @page
-                tokenStream.mustMatch(Tokens.FONT_FACE_SYM);
-                line = tokenStream.token().startLine;
-                col = tokenStream.token().startCol;
-
-                this._readWhitespace();
-
-                this.fire({
-                    type:   "startfontface",
-                    line:   line,
-                    col:    col
-                });
-
-                this._readDeclarations(true);
-
-                this.fire({
-                    type:   "endfontface",
-                    line:   line,
-                    col:    col
-                });
-            },
-
-            _viewport: function() {
-                /*
-                 * viewport
-                 *   : VIEWPORT_SYM S*
-                 *     '{' S* declaration? [ ';' S* declaration? ]* '}' S*
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream,
-                    line,
-                    col;
-
-                tokenStream.mustMatch(Tokens.VIEWPORT_SYM);
-                line = tokenStream.token().startLine;
-                col = tokenStream.token().startCol;
-
-                this._readWhitespace();
-
-                this.fire({
-                    type:   "startviewport",
-                    line:   line,
-                    col:    col
-                });
-
-                this._readDeclarations(true);
-
-                this.fire({
-                    type:   "endviewport",
-                    line:   line,
-                    col:    col
-                });
-
-            },
-
-            _document: function() {
-                /*
-                 * document
-                 *   : DOCUMENT_SYM S*
-                 *     _document_function [ ',' S* _document_function ]* S*
-                 *     '{' S* ruleset* '}'
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    token,
-                    functions = [],
-                    prefix = "";
-
-                tokenStream.mustMatch(Tokens.DOCUMENT_SYM);
-                token = tokenStream.token();
-                if (/^@\-([^\-]+)\-/.test(token.value)) {
-                    prefix = RegExp.$1;
-                }
-
-                this._readWhitespace();
-                functions.push(this._document_function());
-
-                while (tokenStream.match(Tokens.COMMA)) {
-                    this._readWhitespace();
-                    functions.push(this._document_function());
-                }
-
-                tokenStream.mustMatch(Tokens.LBRACE);
-
-                this.fire({
-                    type:      "startdocument",
-                    functions: functions,
-                    prefix:    prefix,
-                    line:      token.startLine,
-                    col:       token.startCol
-                });
-
-                this._readWhitespace(); // Stylus hack
-
-                var ok = true;
-                while (ok) {
-                    switch (tokenStream.peek()) {
-                        case Tokens.PAGE_SYM:
-                            this._page();
-                            break;
-                        case Tokens.FONT_FACE_SYM:
-                            this._font_face();
-                            break;
-                        case Tokens.VIEWPORT_SYM:
-                            this._viewport();
-                            break;
-                        case Tokens.MEDIA_SYM:
-                            this._media();
-                            break;
-                        case Tokens.KEYFRAMES_SYM:
-                            this._keyframes();
-                            break;
-                        case Tokens.DOCUMENT_SYM:
-                            this._document();
-                            break;
-                        case Tokens.SUPPORTS_SYM:
-                            this._supports();
-                            break;
-                        default:
-                            ok = Boolean(this._ruleset());
-                    }
-                }
-
-                tokenStream.mustMatch(Tokens.RBRACE);
-                token = tokenStream.token();
-
-                this.fire({
-                    type:      "enddocument",
-                    functions: functions,
-                    prefix:    prefix,
-                    line:      token.startLine,
-                    col:       token.startCol
-                });
-
-                this._readWhitespace();
-            },
-
-            _document_function: function() {
-                /*
-                 * document_function
-                 *   : function | URI S*
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    value;
-
-                if (tokenStream.match(Tokens.URI)) {
-                    value = tokenStream.token().value;
-                    this._readWhitespace();
-                } else {
-                    value = this._function();
-                    value = value && value.text;
-                }
-
-                return value;
-            },
-
-            _operator: function(inFunction) {
-
-                /*
-                 * operator (outside function)
-                 *  : '/' S* | ',' S* | /( empty )/
-                 * operator (inside function)
-                 *  : '/' S* | '+' S* | '*' S* | '-' S* /( empty )/
-                 *  ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    token       = null;
-
-                if (tokenStream.match([Tokens.SLASH, Tokens.COMMA]) ||
-                    (inFunction && tokenStream.match([Tokens.PLUS, Tokens.STAR, Tokens.MINUS]))) {
-                    token =  tokenStream.token();
-                    this._readWhitespace();
-                }
-                return token ? PropertyValuePart.fromToken(token) : null;
-
-            },
-
-            _combinator: function() {
-
-                /*
-                 * combinator
-                 *  : PLUS S* | GREATER S* | TILDE S* | S+
-                 *  ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    value       = null,
-                    token;
-
-                if (tokenStream.match([Tokens.PLUS, Tokens.GREATER, Tokens.TILDE])) {
-                    token = tokenStream.token();
-                    value = new Combinator(token.value, token.startLine, token.startCol);
-                    this._readWhitespace();
-                }
-
-                return value;
-            },
-
-            _unary_operator: function() {
-
-                /*
-                 * unary_operator
-                 *  : '-' | '+'
-                 *  ;
-                 */
-
-                var tokenStream = this._tokenStream;
-
-                if (tokenStream.match([Tokens.MINUS, Tokens.PLUS])) {
-                    return tokenStream.token().value;
-                } else {
-                    return null;
-                }
-            },
-
-            _property: function() {
-
-                /*
-                 * property
-                 *   : IDENT S*
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    value       = null,
-                    hack        = null,
-                    tokenValue,
-                    token,
-                    line,
-                    col;
-
-                //check for star hack - throws error if not allowed
-                if (tokenStream.peek() === Tokens.STAR && this.options.starHack) {
-                    tokenStream.get();
-                    token = tokenStream.token();
-                    hack = token.value;
-                    line = token.startLine;
-                    col = token.startCol;
-                }
-
-                if (tokenStream.match(Tokens.IDENT)) {
-                    token = tokenStream.token();
-                    tokenValue = token.value;
-
-                    //check for underscore hack - no error if not allowed because it's valid CSS syntax
-                    if (tokenValue.charAt(0) === "_" && this.options.underscoreHack) {
-                        hack = "_";
-                        tokenValue = tokenValue.substring(1);
-                    }
-
-                    value = new PropertyName(tokenValue, hack, (line||token.startLine), (col||token.startCol));
-                    this._readWhitespace();
-                }
-
-                return value;
-            },
-
-            //Augmented with CSS3 Selectors
-            _ruleset: function() {
-                /*
-                 * ruleset
-                 *   : selectors_group
-                 *     '{' S* declaration? [ ';' S* declaration? ]* '}' S*
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    tt,
-                    selectors;
-
-
-                /*
-                 * Error Recovery: If even a single selector fails to parse,
-                 * then the entire ruleset should be thrown away.
-                 */
-                try {
-                    selectors = this._selectors_group();
-                } catch (ex) {
-                    if (ex instanceof SyntaxError && !this.options.strict) {
-
-                        //fire error event
-                        this.fire({
-                            type:       "error",
-                            error:      ex,
-                            message:    ex.message,
-                            line:       ex.line,
-                            col:        ex.col
-                        });
-
-                        //skip over everything until closing brace
-                        tt = tokenStream.advance([Tokens.RBRACE]);
-                        if (tt === Tokens.RBRACE) {
-                            //if there's a right brace, the rule is finished so don't do anything
-                        } else {
-                            //otherwise, rethrow the error because it wasn't handled properly
-                            throw ex;
-                        }
-
-                    } else {
-                        //not a syntax error, rethrow it
-                        throw ex;
-                    }
-
-                    //trigger parser to continue
-                    return true;
-                }
-
-                //if it got here, all selectors parsed
-                if (selectors) {
-
-                    this.fire({
-                        type:       "startrule",
-                        selectors:  selectors,
-                        line:       selectors[0].line,
-                        col:        selectors[0].col
-                    });
-
-                    this._readDeclarations(true);
-
-                    this.fire({
-                        type:       "endrule",
-                        selectors:  selectors,
-                        line:       selectors[0].line,
-                        col:        selectors[0].col
-                    });
-
-                }
-
-                return selectors;
-
-            },
-
-            //CSS3 Selectors
-            _selectors_group: function() {
-
-                /*
-                 * selectors_group
-                 *   : selector [ COMMA S* selector ]*
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream,
-                    selectors   = [],
-                    selector;
-
-                selector = this._selector();
-                if (selector !== null) {
-
-                    selectors.push(selector);
-                    while (tokenStream.match(Tokens.COMMA)) {
-                        this._readWhitespace();
-                        selector = this._selector();
-                        if (selector !== null) {
-                            selectors.push(selector);
-                        } else {
-                            this._unexpectedToken(tokenStream.LT(1));
-                        }
-                    }
-                }
-
-                return selectors.length ? selectors : null;
-            },
-
-            //CSS3 Selectors
-            _selector: function() {
-                /*
-                 * selector
-                 *   : simple_selector_sequence [ combinator simple_selector_sequence ]*
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    selector    = [],
-                    nextSelector = null,
-                    combinator  = null,
-                    ws          = null;
-
-                //if there's no simple selector, then there's no selector
-                nextSelector = this._simple_selector_sequence();
-                if (nextSelector === null) {
-                    return null;
-                }
-
-                selector.push(nextSelector);
-
-                do {
-
-                    //look for a combinator
-                    combinator = this._combinator();
-
-                    if (combinator !== null) {
-                        selector.push(combinator);
-                        nextSelector = this._simple_selector_sequence();
-
-                        //there must be a next selector
-                        if (nextSelector === null) {
-                            this._unexpectedToken(tokenStream.LT(1));
-                        } else {
-
-                            //nextSelector is an instance of SelectorPart
-                            selector.push(nextSelector);
-                        }
-                    } else {
-
-                        //if there's not whitespace, we're done
-                        if (this._readWhitespace()) {
-
-                            //add whitespace separator
-                            ws = new Combinator(tokenStream.token().value, tokenStream.token().startLine, tokenStream.token().startCol);
-
-                            //combinator is not required
-                            combinator = this._combinator();
-
-                            //selector is required if there's a combinator
-                            nextSelector = this._simple_selector_sequence();
-                            if (nextSelector === null) {
-                                if (combinator !== null) {
-                                    this._unexpectedToken(tokenStream.LT(1));
-                                }
-                            } else {
-
-                                if (combinator !== null) {
-                                    selector.push(combinator);
-                                } else {
-                                    selector.push(ws);
-                                }
-
-                                selector.push(nextSelector);
-                            }
-                        } else {
-                            break;
-                        }
-
-                    }
-                } while (true);
-
-                return new Selector(selector, selector[0].line, selector[0].col);
-            },
-
-            //CSS3 Selectors
-            _simple_selector_sequence: function() {
-                /*
-                 * simple_selector_sequence
-                 *   : [ type_selector | universal ]
-                 *     [ HASH | class | attrib | pseudo | any | negation ]*
-                 *   | [ HASH | class | attrib | pseudo | any | negation ]+
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-
-                    //parts of a simple selector
-                    elementName = null,
-                    modifiers   = [],
-
-                    //complete selector text
-                    selectorText= "",
-
-                    //the different parts after the element name to search for
-                    components  = [
-                        //HASH
-                        function() {
-                            return tokenStream.match(Tokens.HASH) ?
-                                    new SelectorSubPart(tokenStream.token().value, "id", tokenStream.token().startLine, tokenStream.token().startCol) :
-                                    null;
-                        },
-                        this._class,
-                        this._attrib,
-                        this._pseudo,
-                        this._any,
-                        this._negation
-                    ],
-                    i           = 0,
-                    len         = components.length,
-                    component   = null,
-                    line,
-                    col;
-
-
-                //get starting line and column for the selector
-                line = tokenStream.LT(1).startLine;
-                col = tokenStream.LT(1).startCol;
-
-                elementName = this._type_selector();
-                if (!elementName) {
-                    elementName = this._universal();
-                }
-
-                if (elementName !== null) {
-                    selectorText += elementName;
-                }
-
-                while (true) {
-
-                    //whitespace means we're done
-                    if (tokenStream.peek() === Tokens.S) {
-                        break;
-                    }
-
-                    //check for each component
-                    while (i < len && component === null) {
-                        component = components[i++].call(this);
-                    }
-
-                    if (component === null) {
-
-                        //we don't have a selector
-                        if (selectorText === "") {
-                            return null;
-                        } else {
-                            break;
-                        }
-                    } else {
-                        i = 0;
-                        modifiers.push(component);
-                        selectorText += component.toString();
-                        component = null;
-                    }
-                }
-
-
-                return selectorText !== "" ?
-                        new SelectorPart(elementName, modifiers, selectorText, line, col) :
-                        null;
-            },
-
-            //CSS3 Selectors
-            _type_selector: function() {
-                /*
-                 * type_selector
-                 *   : [ namespace_prefix ]? element_name
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    ns          = this._namespace_prefix(),
-                    elementName = this._element_name();
-
-                if (!elementName) {
-                    /*
-                     * Need to back out the namespace that was read due to both
-                     * type_selector and universal reading namespace_prefix
-                     * first. Kind of hacky, but only way I can figure out
-                     * right now how to not change the grammar.
-                     */
-                    if (ns) {
-                        tokenStream.unget();
-                        if (ns.length > 1) {
-                            tokenStream.unget();
-                        }
-                    }
-
-                    return null;
-                } else {
-                    if (ns) {
-                        elementName.text = ns + elementName.text;
-                        elementName.col -= ns.length;
-                    }
-                    return elementName;
-                }
-            },
-
-            //CSS3 Selectors
-            _class: function() {
-                /*
-                 * class
-                 *   : '.' IDENT
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    token;
-
-                if (tokenStream.match(Tokens.DOT)) {
-                    tokenStream.mustMatch(Tokens.IDENT);
-                    token = tokenStream.token();
-                    return new SelectorSubPart("." + token.value, "class", token.startLine, token.startCol - 1);
-                } else {
-                    return null;
-                }
-
-            },
-
-            //CSS3 Selectors
-            _element_name: function() {
-                /*
-                 * element_name
-                 *   : IDENT
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    token;
-
-                if (tokenStream.match(Tokens.IDENT)) {
-                    token = tokenStream.token();
-                    return new SelectorSubPart(token.value, "elementName", token.startLine, token.startCol);
-
-                } else {
-                    return null;
-                }
-            },
-
-            //CSS3 Selectors
-            _namespace_prefix: function() {
-                /*
-                 * namespace_prefix
-                 *   : [ IDENT | '*' ]? '|'
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream,
-                    value       = "";
-
-                //verify that this is a namespace prefix
-                if (tokenStream.LA(1) === Tokens.PIPE || tokenStream.LA(2) === Tokens.PIPE) {
-
-                    if (tokenStream.match([Tokens.IDENT, Tokens.STAR])) {
-                        value += tokenStream.token().value;
-                    }
-
-                    tokenStream.mustMatch(Tokens.PIPE);
-                    value += "|";
-
-                }
-
-                return value.length ? value : null;
-            },
-
-            //CSS3 Selectors
-            _universal: function() {
-                /*
-                 * universal
-                 *   : [ namespace_prefix ]? '*'
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream,
-                    value       = "",
-                    ns;
-
-                ns = this._namespace_prefix();
-                if (ns) {
-                    value += ns;
-                }
-
-                if (tokenStream.match(Tokens.STAR)) {
-                    value += "*";
-                }
-
-                return value.length ? value : null;
-
-            },
-
-            //CSS3 Selectors
-            _attrib: function() {
-                /*
-                 * attrib
-                 *   : '[' S* [ namespace_prefix ]? IDENT S*
-                 *         [ [ PREFIXMATCH |
-                 *             SUFFIXMATCH |
-                 *             SUBSTRINGMATCH |
-                 *             '=' |
-                 *             INCLUDES |
-                 *             DASHMATCH ] S* [ IDENT | STRING ] S*
-                 *         ]? ']'
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    value       = null,
-                    ns,
-                    token;
-
-                if (tokenStream.match(Tokens.LBRACKET)) {
-                    token = tokenStream.token();
-                    value = token.value;
-                    value += this._readWhitespace();
-
-                    ns = this._namespace_prefix();
-
-                    if (ns) {
-                        value += ns;
-                    }
-
-                    tokenStream.mustMatch(Tokens.IDENT);
-                    value += tokenStream.token().value;
-                    value += this._readWhitespace();
-
-                    if (tokenStream.match([Tokens.PREFIXMATCH, Tokens.SUFFIXMATCH, Tokens.SUBSTRINGMATCH,
-                            Tokens.EQUALS, Tokens.INCLUDES, Tokens.DASHMATCH])) {
-
-                        value += tokenStream.token().value;
-                        value += this._readWhitespace();
-
-                        tokenStream.mustMatch([Tokens.IDENT, Tokens.STRING]);
-                        value += tokenStream.token().value;
-                        value += this._readWhitespace();
-
-                        if (tokenStream.match([Tokens.IDENT])) {
-                            if (tokenStream.token().value.toLowerCase() == 'i') {
-                                value += tokenStream.token().value;
-                                value += this._readWhitespace();
-                            } else {
-                                tokenStream.unget();
-                            }
-                        }
-                    }
-
-                    tokenStream.mustMatch(Tokens.RBRACKET);
-
-                    return new SelectorSubPart(value + "]", "attribute", token.startLine, token.startCol);
-                } else {
-                    return null;
-                }
-            },
-
-            //CSS3 Selectors
-            _pseudo: function() {
-
-                /*
-                 * pseudo
-                 *   : ':' ':'? [ IDENT | functional_pseudo ]
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    pseudo      = null,
-                    colons      = ":",
-                    line,
-                    col;
-
-                if (tokenStream.match(Tokens.COLON)) {
-
-                    if (tokenStream.match(Tokens.COLON)) {
-                        colons += ":";
-                    }
-
-                    if (tokenStream.match(Tokens.IDENT)) {
-                        pseudo = tokenStream.token().value;
-                        line = tokenStream.token().startLine;
-                        col = tokenStream.token().startCol - colons.length;
-                    } else if (tokenStream.peek() === Tokens.FUNCTION) {
-                        line = tokenStream.LT(1).startLine;
-                        col = tokenStream.LT(1).startCol - colons.length;
-                        pseudo = this._functional_pseudo();
-                    }
-
-                    if (pseudo) {
-                        pseudo = new SelectorSubPart(colons + pseudo, "pseudo", line, col);
-                    } else {
-                        var startLine = tokenStream.LT(1).startLine,
-                            startCol  = tokenStream.LT(0).startCol;
-                        throw new SyntaxError("Expected a `FUNCTION` or `IDENT` after colon at line " + startLine + ", col " + startCol + ".", startLine, startCol);
-                    }
-                }
-
-                return pseudo;
-            },
-
-            //CSS3 Selectors
-            _functional_pseudo: function() {
-                /*
-                 * functional_pseudo
-                 *   : FUNCTION S* expression ')'
-                 *   ;
-                */
-
-                var tokenStream = this._tokenStream,
-                    value = null;
-
-                if (tokenStream.match(Tokens.FUNCTION)) {
-                    value = tokenStream.token().value;
-                    value += this._readWhitespace();
-                    value += this._expression();
-                    tokenStream.mustMatch(Tokens.RPAREN);
-                    value += ")";
-                }
-
-                return value;
-            },
-
-            //CSS3 Selectors
-            _expression: function() {
-                /*
-                 * expression
-                 *   : [ [ PLUS | '-' | DIMENSION | NUMBER | STRING | IDENT ] S* ]+
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    value       = "";
-
-                while (tokenStream.match([Tokens.PLUS, Tokens.MINUS, Tokens.DIMENSION,
-                        Tokens.NUMBER, Tokens.STRING, Tokens.IDENT, Tokens.LENGTH,
-                        Tokens.FREQ, Tokens.ANGLE, Tokens.TIME,
-                        Tokens.RESOLUTION, Tokens.SLASH])) {
-
-                    value += tokenStream.token().value;
-                    value += this._readWhitespace();
-                }
-
-                return value.length ? value : null;
-
-            },
-
-            //CSS3 Selectors
-            _any: function() {
-                /*
-                 * any
-                 *   : ANY S* any_arg S* ')'
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    line,
-                    col,
-                    value       = "",
-                    arg,
-                    subpart     = null;
-
-                if (tokenStream.match(Tokens.ANY)) {
-                    value = tokenStream.token().value;
-                    line = tokenStream.token().startLine;
-                    col = tokenStream.token().startCol;
-                    value += this._readWhitespace();
-                    arg = this._selectors_group();
-                    value += arg;
-                    value += this._readWhitespace();
-                    tokenStream.match(Tokens.RPAREN);
-                    value += tokenStream.token().value;
-
-                    subpart = new SelectorSubPart(value, "any", line, col);
-                    subpart.args.push(arg);
-                }
-
-                return subpart;
-            },
-
-            //CSS3 Selectors
-            _negation: function() {
-                /*
-                 * negation
-                 *   : NOT S* negation_arg S* ')'
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    line,
-                    col,
-                    value       = "",
-                    arg,
-                    subpart     = null;
-
-                if (tokenStream.match(Tokens.NOT)) {
-                    value = tokenStream.token().value;
-                    line = tokenStream.token().startLine;
-                    col = tokenStream.token().startCol;
-                    value += this._readWhitespace();
-                    arg = this._negation_arg();
-                    value += arg;
-                    value += this._readWhitespace();
-                    tokenStream.match(Tokens.RPAREN);
-                    value += tokenStream.token().value;
-
-                    subpart = new SelectorSubPart(value, "not", line, col);
-                    subpart.args.push(arg);
-                }
-
-                return subpart;
-            },
-
-            //CSS3 Selectors
-            _negation_arg: function() {
-                /*
-                 * negation_arg
-                 *   : type_selector | universal | HASH | class | attrib | pseudo
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    args        = [
-                        this._type_selector,
-                        this._universal,
-                        function() {
-                            return tokenStream.match(Tokens.HASH) ?
-                                    new SelectorSubPart(tokenStream.token().value, "id", tokenStream.token().startLine, tokenStream.token().startCol) :
-                                    null;
-                        },
-                        this._class,
-                        this._attrib,
-                        this._pseudo
-                    ],
-                    arg         = null,
-                    i           = 0,
-                    len         = args.length,
-                    line,
-                    col,
-                    part;
-
-                line = tokenStream.LT(1).startLine;
-                col = tokenStream.LT(1).startCol;
-
-                while (i < len && arg === null) {
-
-                    arg = args[i].call(this);
-                    i++;
-                }
-
-                //must be a negation arg
-                if (arg === null) {
-                    this._unexpectedToken(tokenStream.LT(1));
-                }
-
-                //it's an element name
-                if (arg.type === "elementName") {
-                    part = new SelectorPart(arg, [], arg.toString(), line, col);
-                } else {
-                    part = new SelectorPart(null, [arg], arg.toString(), line, col);
-                }
-
-                return part;
-            },
-
-            _declaration: function() {
-
-                /*
-                 * declaration
-                 *   : property ':' S* expr prio?
-                 *   | /( empty )/
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    property    = null,
-                    expr        = null,
-                    prio        = null,
-                    invalid     = null,
-                    propertyName= "";
-
-                property = this._property();
-                if (property !== null) {
-
-                    tokenStream.mustMatch(Tokens.COLON);
-
-                    // whitespace is a part of custom property value
-                    if (property.text.startsWith("--")) {
-                        expr = this._customProperty();
-                    } else {
-                        this._readWhitespace();
-                        expr = this._expr();
-                    }
-
-                    //if there's no parts for the value, it's an error
-                    if (!expr || expr.length === 0) {
-                        this._unexpectedToken(tokenStream.LT(1));
-                    }
-
-                    prio = this._prio();
-
-                    /*
-                     * If hacks should be allowed, then only check the root
-                     * property. If hacks should not be allowed, treat
-                     * _property or *property as invalid properties.
-                     */
-                    propertyName = property.toString();
-                    if (this.options.starHack && property.hack === "*" ||
-                            this.options.underscoreHack && property.hack === "_") {
-
-                        propertyName = property.text;
-                    }
-
-                    try {
-                        this._validateProperty(propertyName, expr);
-                    } catch (ex) {
-                        invalid = ex;
-                    }
-
-                    this.fire({
-                        type:       "property",
-                        property:   property,
-                        value:      expr,
-                        important:  prio,
-                        line:       property.line,
-                        col:        property.col,
-                        invalid:    invalid
-                    });
-
-                    return true;
-                } else {
-                    return false;
-                }
-            },
-
-            _prio: function() {
-                /*
-                 * prio
-                 *   : IMPORTANT_SYM S*
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    result      = tokenStream.match(Tokens.IMPORTANT_SYM);
-
-                this._readWhitespace();
-                return result;
-            },
-
-            _expr: function(inFunction) {
-                /*
-                 * expr
-                 *   : term [ operator term ]*
-                 *   ;
-                 */
-
-                var values      = [],
-                    //valueParts    = [],
-                    value       = null,
-                    operator    = null;
-
-                value = this._term(inFunction);
-                if (value !== null) {
-
-                    values.push(value);
-
-                    do {
-                        operator = this._operator(inFunction);
-
-                        //if there's an operator, keep building up the value parts
-                        if (operator) {
-                            values.push(operator);
-                        } /*else {
-                            //if there's not an operator, you have a full value
-                            values.push(new PropertyValue(valueParts, valueParts[0].line, valueParts[0].col));
-                            valueParts = [];
-                        }*/
-
-                        value = this._term(inFunction);
-
-                        if (value === null) {
-                            break;
-                        }
-                        const last = values[values.length - 1];
-                        if (last && last.line === value.line && last.col === value.col && last.text === value.text) {
-                            break;
-                        }
-                        values.push(value);
-                    } while (true);
-                }
-
-                //cleanup
-                /*if (valueParts.length) {
-                    values.push(new PropertyValue(valueParts, valueParts[0].line, valueParts[0].col));
-                }*/
-
-                return values.length > 0 ? new PropertyValue(values, values[0].line, values[0].col) : null;
-            },
-
-            _customProperty: function() {
-                const reader = this._tokenStream._reader;
-                const value = [];
-
-                const endings = [];
-                // a custom property value may end before these characters
-                // that belong to the parent declaration, not to the custom property
-                let end = /[;!})]/;
-
-                readValue:
-                while (!reader.eof()) {
-                    const chunk = reader.readMatch(/([^;!'"{}()[\]/]|\/(?!\*))+/y);
-                    if (chunk) value.push(chunk);
-
-                    reader.mark();
-                    let c = reader.read();
-                    value.push(c);
-
-                    switch (c) {
-                        case '/':
-                            value.push(reader.readMatch(/([^*]|\*(?!\/))*(\*\/|$)/y));
-                            continue;
-                        case '"':
-                        case "'":
-                            reader.reset();
-                            value.pop();
-                            value.push(this._tokenStream.readString());
-                            continue;
-                        case '{':
-                            endings.push(end);
-                            end = '}';
-                            continue;
-                        case '(':
-                            endings.push(end);
-                            end = ')';
-                            continue;
-                        case '[':
-                            endings.push(end);
-                            end = ']';
-                            continue;
-                        case ';':
-                        case '!':
-                            if (endings.length) continue;
-                            reader.reset();
-                            // fallthrough
-                        case '}':
-                        case ')':
-                        case ']':
-                            if (end instanceof RegExp ? !end.test(c) : c !== end) {
-                                reader.reset();
-                                return null;
-                            }
-                            end = endings.pop();
-                            if (end) continue;
-                            if (c === '}' || c === ')') {
-                                // unget parent }
-                                reader.reset();
-                                value.pop();
-                            }
-                            break readValue;
-                    }
-                }
-                if (!value[0]) return null;
-                const {startCol: col, startLine: line} = this._tokenStream._token;
-                return new PropertyValue([
-                    new PropertyValuePart(value.join(''), line, col),
-                ], line, col);
-            },
-
-            _term: function(inFunction) {
-
-                /*
-                 * term
-                 *   : unary_operator?
-                 *     [ NUMBER S* | PERCENTAGE S* | LENGTH S* | ANGLE S* |
-                 *       TIME S* | FREQ S* | function | ie_function ]
-                 *   | STRING S* | IDENT S* | URI S* | UNICODERANGE S* | hexcolor
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    unary       = null,
-                    value       = null,
-                    endChar     = null,
-                    part        = null,
-                    token,
-                    line,
-                    col;
-
-                //returns the operator or null
-                unary = this._unary_operator();
-                if (unary !== null) {
-                    line = tokenStream.token().startLine;
-                    col = tokenStream.token().startCol;
-                }
-
-                //exception for IE filters
-                if (tokenStream.peek() === Tokens.IE_FUNCTION && this.options.ieFilters) {
-
-                    value = this._ie_function();
-                    if (unary === null) {
-                        line = tokenStream.token().startLine;
-                        col = tokenStream.token().startCol;
-                    }
-
-                //see if it's a simple block
-                } else if (inFunction && tokenStream.match([Tokens.LPAREN, Tokens.LBRACE, Tokens.LBRACKET])) {
-
-                    token = tokenStream.token();
-                    endChar = token.endChar;
-                    value = token.value + this._expr(inFunction).text;
-                    if (unary === null) {
-                        line = tokenStream.token().startLine;
-                        col = tokenStream.token().startCol;
-                    }
-                    tokenStream.mustMatch(Tokens.type(endChar));
-                    value += endChar;
-                    this._readWhitespace();
-
-                //see if there's a simple match
-                } else if (tokenStream.match([Tokens.NUMBER, Tokens.PERCENTAGE, Tokens.LENGTH,
-                        Tokens.ANGLE, Tokens.TIME, Tokens.DIMENSION,
-                        Tokens.FREQ, Tokens.STRING, Tokens.IDENT, Tokens.URI, Tokens.UNICODE_RANGE])) {
-
-                    value = tokenStream.token().value;
-                    if (unary === null) {
-                        line = tokenStream.token().startLine;
-                        col = tokenStream.token().startCol;
-                        // Correct potentially-inaccurate IDENT parsing in
-                        // PropertyValuePart constructor.
-                        part = PropertyValuePart.fromToken(tokenStream.token());
-                    }
-                    this._readWhitespace();
-                } else {
-
-                    //see if it's a color
-                    token = this._hexcolor();
-                    if (token === null) {
-
-                        //if there's no unary, get the start of the next token for line/col info
-                        if (unary === null) {
-                            line = tokenStream.LT(1).startLine;
-                            col = tokenStream.LT(1).startCol;
-                        }
-
-                        //has to be a function
-                        if (value === null) {
-
-                            /*
-                             * This checks for alpha(opacity=0) style of IE
-                             * functions. IE_FUNCTION only presents progid: style.
-                             */
-                            if (tokenStream.LA(3) === Tokens.EQUALS && this.options.ieFilters) {
-                                value = this._ie_function();
-                            } else {
-                                value = this._function();
-                                if (value) {
-                                    part = new PropertyValuePart(unary !== null ? unary + value.text : value.text, line, col);
-                                    part.expr = value.expr;
-                                }
-                            }
-                        }
-
-                        if (value === null) {
-                            const usoVar = this._isUsoVar();
-                            if (usoVar) {
-                                ([line, col, value] = usoVar);
-                            }
-                        }
-
-                        /*if (value === null) {
-                            return null;
-                            //throw new Error("Expected identifier at line " + tokenStream.token().startLine + ", character " +  tokenStream.token().startCol + ".");
-                        }*/
-
-                    } else {
-                        value = token.value;
-                        if (unary === null) {
-                            line = token.startLine;
-                            col = token.startCol;
-                        }
-                    }
-
-                }
-
-                return part !== null ? part : value !== null ?
-                        new PropertyValuePart(unary !== null ? unary + value : value, line, col) :
-                        null;
-
-            },
-
-            _function() {
-
-                /*
-                 * function
-                 *   : FUNCTION S* expr ')' S*
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    functionText = [],
-                    expr        = null,
-                    lt;
-
-                if (tokenStream.match(Tokens.FUNCTION)) {
-                    functionText.push(tokenStream.token().value);
-                    this._readWhitespace();
-                    expr = this._expr(true);
-                    functionText.push(String(expr));
-
-                    //START: Horrible hack in case it's an IE filter
-                    if (this.options.ieFilters && tokenStream.peek() === Tokens.EQUALS) {
-                        do {
-
-                            if (this._readWhitespace()) {
-                                functionText.push(tokenStream.token().value);
-                            }
-
-                            //might be second time in the loop
-                            if (tokenStream.LA(0) === Tokens.COMMA) {
-                                functionText.push(tokenStream.token().value);
-                            }
-
-                            tokenStream.match(Tokens.IDENT);
-                            functionText.push(tokenStream.token().value);
-
-                            tokenStream.match(Tokens.EQUALS);
-                            functionText.push(tokenStream.token().value);
-
-                            //functionText.push(this._term());
-                            lt = tokenStream.peek();
-                            while (lt !== Tokens.COMMA && lt !== Tokens.S && lt !== Tokens.RPAREN && lt !== Tokens.EOF) {
-                                tokenStream.get();
-                                functionText.push(tokenStream.token().value);
-                                lt = tokenStream.peek();
-                            }
-                        } while (tokenStream.match([Tokens.COMMA, Tokens.S]));
-                    }
-
-                    //END: Horrible Hack
-
-                    tokenStream.mustMatch(Tokens.RPAREN);
-                    functionText.push(")");
-                    this._readWhitespace();
-                }
-
-                return !functionText[0] ? null : {expr, text: functionText.join('')};
-            },
-
-            _ie_function: function() {
-
-                /* (My own extension)
-                 * ie_function
-                 *   : IE_FUNCTION S* IDENT '=' term [S* ','? IDENT '=' term]+ ')' S*
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    functionText = null,
-                    lt;
-
-                //IE function can begin like a regular function, too
-                if (tokenStream.match([Tokens.IE_FUNCTION, Tokens.FUNCTION])) {
-                    functionText = tokenStream.token().value;
-
-                    do {
-
-                        if (this._readWhitespace()) {
-                            functionText += tokenStream.token().value;
-                        }
-
-                        //might be second time in the loop
-                        if (tokenStream.LA(0) === Tokens.COMMA) {
-                            functionText += tokenStream.token().value;
-                        }
-
-                        tokenStream.match(Tokens.IDENT);
-                        functionText += tokenStream.token().value;
-
-                        tokenStream.match(Tokens.EQUALS);
-                        functionText += tokenStream.token().value;
-
-                        //functionText += this._term();
-                        lt = tokenStream.peek();
-                        while (lt !== Tokens.COMMA && lt !== Tokens.S && lt !== Tokens.RPAREN) {
-                            tokenStream.get();
-                            functionText += tokenStream.token().value;
-                            lt = tokenStream.peek();
-                        }
-                    } while (tokenStream.match([Tokens.COMMA, Tokens.S]));
-
-                    tokenStream.match(Tokens.RPAREN);
-                    functionText += ")";
-                    this._readWhitespace();
-                }
-
-                return functionText;
-            },
-
-            _hexcolor: function() {
-                /*
-                 * There is a constraint on the color that it must
-                 * have either 3,4 or 6,8 hex-digits (i.e., [0-9a-fA-F])
-                 * after the "#"; e.g., "#000" is OK, but "#abcd" is not.
-                 *
-                 * hexcolor
-                 *   : HASH S*
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    token = null,
-                    color;
-
-                if (tokenStream.match(Tokens.HASH)) {
-                    token = tokenStream.token();
-                    color = token.value;
-                    const len = color.length;
-                    if (len !== 4 && len !== 5 && len !== 7 && len !== 9 ||
-                            !/^#([a-f\d]{3}(?:[a-f\d](?:[a-f\d]{2}){0,2})?)$/i.test(color)) {
-                        throw new SyntaxError("Expected a hex color but found '" + color + "' at line " + token.startLine + ", col " + token.startCol + ".", token.startLine, token.startCol);
-                    }
-                    this._readWhitespace();
-                }
-
-                return token;
-            },
-
-            //-----------------------------------------------------------------
-            // Animations methods
-            //-----------------------------------------------------------------
-
-            _keyframes: function() {
-
-                /*
-                 * keyframes:
-                 *   : KEYFRAMES_SYM S* keyframe_name S* '{' S* keyframe_rule* '}' {
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream,
-                    token,
-                    tt,
-                    name,
-                    prefix = "";
-
-                tokenStream.mustMatch(Tokens.KEYFRAMES_SYM);
-                token = tokenStream.token();
-                if (/^@\-([^\-]+)\-/.test(token.value)) {
-                    prefix = RegExp.$1;
-                }
-
-                this._readWhitespace();
-                name = this._keyframe_name();
-
-                this._readWhitespace();
-                tokenStream.mustMatch(Tokens.LBRACE);
-
-                this.fire({
-                    type:   "startkeyframes",
-                    name:   name,
-                    prefix: prefix,
-                    line:   token.startLine,
-                    col:    token.startCol
-                });
-
-                this._readWhitespace();
-                tt = tokenStream.peek();
-
-                //check for key
-                while (tt === Tokens.IDENT || tt === Tokens.PERCENTAGE) {
-                    this._keyframe_rule();
-                    this._readWhitespace();
-                    tt = tokenStream.peek();
-                }
-
-                this.fire({
-                    type:   "endkeyframes",
-                    name:   name,
-                    prefix: prefix,
-                    line:   token.startLine,
-                    col:    token.startCol
-                });
-
-                this._readWhitespace();
-                tokenStream.mustMatch(Tokens.RBRACE);
-                this._readWhitespace();
-
-            },
-
-            _keyframe_name: function() {
-
-                /*
-                 * keyframe_name:
-                 *   : IDENT
-                 *   | STRING
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream;
-
-                tokenStream.mustMatch([Tokens.IDENT, Tokens.STRING]);
-                return SyntaxUnit.fromToken(tokenStream.token());
-            },
-
-            _keyframe_rule: function() {
-
-                /*
-                 * keyframe_rule:
-                 *   : key_list S*
-                 *     '{' S* declaration [ ';' S* declaration ]* '}' S*
-                 *   ;
-                 */
-                var keyList = this._key_list();
-
-                this.fire({
-                    type:   "startkeyframerule",
-                    keys:   keyList,
-                    line:   keyList[0].line,
-                    col:    keyList[0].col
-                });
-
-                this._readDeclarations(true);
-
-                this.fire({
-                    type:   "endkeyframerule",
-                    keys:   keyList,
-                    line:   keyList[0].line,
-                    col:    keyList[0].col
-                });
-
-            },
-
-            _key_list: function() {
-
-                /*
-                 * key_list:
-                 *   : key [ S* ',' S* key]*
-                 *   ;
-                 */
-                var tokenStream = this._tokenStream,
-                    keyList = [];
-
-                //must be least one key
-                keyList.push(this._key());
-
-                this._readWhitespace();
-
-                while (tokenStream.match(Tokens.COMMA)) {
-                    this._readWhitespace();
-                    keyList.push(this._key());
-                    this._readWhitespace();
-                }
-
-                return keyList;
-            },
-
-            _key: function() {
-                /*
-                 * There is a restriction that IDENT can be only "from" or "to".
-                 *
-                 * key
-                 *   : PERCENTAGE
-                 *   | IDENT
-                 *   ;
-                 */
-
-                var tokenStream = this._tokenStream,
-                    token;
-
-                if (tokenStream.match(Tokens.PERCENTAGE)) {
-                    return SyntaxUnit.fromToken(tokenStream.token());
-                } else if (tokenStream.match(Tokens.IDENT)) {
-                    token = tokenStream.token();
-
-                    if (/from|to/i.test(token.value)) {
-                        return SyntaxUnit.fromToken(token);
-                    }
-
-                    tokenStream.unget();
-                }
-
-                //if it gets here, there wasn't a valid token, so time to explode
-                this._unexpectedToken(tokenStream.LT(1));
-            },
-
-            //-----------------------------------------------------------------
-            // Helper methods
-            //-----------------------------------------------------------------
-
-            /**
-             * Not part of CSS grammar, but useful for skipping over
-             * combination of white space and HTML-style comments.
-             * @return {void}
-             * @method _skipCruft
-             * @private
-             */
-            _skipCruft: function() {
-                while (this._tokenStream.match([Tokens.S, Tokens.CDO, Tokens.CDC])) {
-                    //noop
-                }
-            },
-
-            /**
-             * Not part of CSS grammar, but this pattern occurs frequently
-             * in the official CSS grammar. Split out here to eliminate
-             * duplicate code.
-             * @param {Boolean} checkStart Indicates if the rule should check
-             *      for the left brace at the beginning.
-             * @param {Boolean} readMargins Indicates if the rule should check
-             *      for margin patterns.
-             * @return {void}
-             * @method _readDeclarations
-             * @private
-             */
-            _readDeclarations: function(checkStart, readMargins) {
-                /*
-                 * Reads the pattern
-                 * S* '{' S* declaration [ ';' S* declaration ]* '}' S*
-                 * or
-                 * S* '{' S* [ declaration | margin ]? [ ';' S* [ declaration | margin ]? ]* '}' S*
-                 * Note that this is how it is described in CSS3 Paged Media, but is actually incorrect.
-                 * A semicolon is only necessary following a declaration if there's another declaration
-                 * or margin afterwards.
-                 */
-                var tokenStream = this._tokenStream,
-                    tt;
-
-
-                this._readWhitespace();
-
-                if (checkStart) {
-                    tokenStream.mustMatch(Tokens.LBRACE);
-                }
-
-                this._readWhitespace();
-
-                try {
-
-                    while (true) {
-
-                        if (tokenStream.match(Tokens.SEMICOLON) || (readMargins && this._margin())) {
-                            //noop
-                        } else if (this._declaration()) {
-                            if (!tokenStream.match(Tokens.SEMICOLON)) {
-                                break;
-                            }
-                        } else {
-                            break;
-                        }
-
-                        //if ((!this._margin() && !this._declaration()) || !tokenStream.match(Tokens.SEMICOLON)){
-                        //    break;
-                        //}
-                        this._readWhitespace();
-                    }
-
-                    tokenStream.mustMatch(Tokens.RBRACE);
-                    this._readWhitespace();
-
-                } catch (ex) {
-                    if (ex instanceof SyntaxError && !this.options.strict) {
-
-                        //fire error event
-                        this.fire({
-                            type:       "error",
-                            error:      ex,
-                            message:    ex.message,
-                            line:       ex.line,
-                            col:        ex.col
-                        });
-
-                        //see if there's another declaration
-                        tt = tokenStream.advance([Tokens.SEMICOLON, Tokens.RBRACE]);
-                        if (tt === Tokens.SEMICOLON) {
-                            //if there's a semicolon, then there might be another declaration
-                            this._readDeclarations(false, readMargins);
-                        } else if (tt !== Tokens.RBRACE) {
-                            //if there's a right brace, the rule is finished so don't do anything
-                            //otherwise, rethrow the error because it wasn't handled properly
-                            throw ex;
-                        }
-
-                    } else {
-                        //not a syntax error, rethrow it
-                        throw ex;
-                    }
-                }
-
-            },
-
-            /**
-             * In some cases, you can end up with two white space tokens in a
-             * row. Instead of making a change in every function that looks for
-             * white space, this function is used to match as much white space
-             * as necessary.
-             * @method _readWhitespace
-             * @return {String} The white space if found, empty string if not.
-             * @private
-             */
-            _readWhitespace: function() {
-
-                var tokenStream = this._tokenStream,
-                    ws = "";
-
-                while (tokenStream.match(Tokens.S)) {
-                    ws += tokenStream.token().value;
-                }
-
-                return ws;
-            },
-
-
-            _isUsoVar() {
-                const tokenStream = this._tokenStream;
-                for (let i = tokenStream._ltIndex - 1; i >= 0; i--) {
-                    const {type, value, startLine, startCol} = tokenStream._lt[i];
-                    if (type === tokenStream._tokenData.S) {
-                        // NOP
-                    } else if (type === tokenStream._tokenData.COMMENT &&
-                            value[2] === '[' && value[3] === '[' && value.endsWith(']]*/')) {
-                        return [startLine, startCol, value];
-                    } else {
-                        return false;
-                    }
-                }
-            },
-
-            /**
-             * Throws an error when an unexpected token is found.
-             * @param {Object} token The token that was found.
-             * @method _unexpectedToken
-             * @return {void}
-             * @private
-             */
-            _unexpectedToken: function(token) {
-                throw new SyntaxError("Unexpected token '" + token.value + "' at line " + token.startLine + ", col " + token.startCol + ".", token.startLine, token.startCol);
-            },
-
-            /**
-             * Helper method used for parsing subparts of a style sheet.
-             * @return {void}
-             * @method _verifyEnd
-             * @private
-             */
-            _verifyEnd: function() {
-                if (this._tokenStream.LA(1) !== Tokens.EOF) {
-                    this._unexpectedToken(this._tokenStream.LT(1));
-                }
-            },
-
-            //-----------------------------------------------------------------
-            // Validation methods
-            //-----------------------------------------------------------------
-            _validateProperty: function(property, value) {
-                Validation.validate(property, value);
-            },
-
-            //-----------------------------------------------------------------
-            // Parsing methods
-            //-----------------------------------------------------------------
-
-            parse: function(input) {
-                this._tokenStream = new TokenStream(input, Tokens);
-                this._stylesheet();
-            },
-
-            parseStyleSheet: function(input) {
-                //just passthrough
-                return this.parse(input);
-            },
-
-            parseMediaQuery: function(input) {
-                this._tokenStream = new TokenStream(input, Tokens);
-                var result = this._media_query();
-
-                //if there's anything more, then it's an invalid selector
-                this._verifyEnd();
-
-                //otherwise return result
-                return result;
-            },
-
-            /**
-             * Parses a property value (everything after the semicolon).
-             * @return {parserlib.css.PropertyValue} The property value.
-             * @throws parserlib.util.SyntaxError If an unexpected token is found.
-             * @method parserPropertyValue
-             */
-            parsePropertyValue: function(input) {
-
-                this._tokenStream = new TokenStream(input, Tokens);
-                this._readWhitespace();
-
-                var result = this._expr();
-
-                //okay to have a trailing white space
-                this._readWhitespace();
-
-                //if there's anything more, then it's an invalid selector
-                this._verifyEnd();
-
-                //otherwise return result
-                return result;
-            },
-
-            /**
-             * Parses a complete CSS rule, including selectors and
-             * properties.
-             * @param {String} input The text to parser.
-             * @return {Boolean} True if the parse completed successfully, false if not.
-             * @method parseRule
-             */
-            parseRule: function(input) {
-                this._tokenStream = new TokenStream(input, Tokens);
-
-                //skip any leading white space
-                this._readWhitespace();
-
-                var result = this._ruleset();
-
-                //skip any trailing white space
-                this._readWhitespace();
-
-                //if there's anything more, then it's an invalid selector
-                this._verifyEnd();
-
-                //otherwise return result
-                return result;
-            },
-
-            /**
-             * Parses a single CSS selector (no comma)
-             * @param {String} input The text to parse as a CSS selector.
-             * @return {Selector} An object representing the selector.
-             * @throws parserlib.util.SyntaxError If an unexpected token is found.
-             * @method parseSelector
-             */
-            parseSelector: function(input) {
-
-                this._tokenStream = new TokenStream(input, Tokens);
-
-                //skip any leading white space
-                this._readWhitespace();
-
-                var result = this._selector();
-
-                //skip any trailing white space
-                this._readWhitespace();
-
-                //if there's anything more, then it's an invalid selector
-                this._verifyEnd();
-
-                //otherwise return result
-                return result;
-            },
-
-            /**
-             * Parses an HTML style attribute: a set of CSS declarations
-             * separated by semicolons.
-             * @param {String} input The text to parse as a style attribute
-             * @return {void}
-             * @method parseStyleAttribute
-             */
-            parseStyleAttribute: function(input) {
-                input += "}"; // for error recovery in _readDeclarations()
-                this._tokenStream = new TokenStream(input, Tokens);
-                this._readDeclarations();
-            }
-        };
-
-    //copy over onto prototype
-    for (prop in additions) {
-        if (Object.prototype.hasOwnProperty.call(additions, prop)) {
-            proto[prop] = additions[prop];
-        }
-    }
-
-    return proto;
-}();
-
-
-/*
-nth
-  : S* [ ['-'|'+']? INTEGER? {N} [ S* ['-'|'+'] S* INTEGER ]? |
-         ['-'|'+']? INTEGER | {O}{D}{D} | {E}{V}{E}{N} ] S*
-  ;
-*/
-
-},{"../util/EventTarget":23,"../util/SyntaxError":25,"../util/SyntaxUnit":26,"./Combinator":2,"./MediaFeature":4,"./MediaQuery":5,"./PropertyName":8,"./PropertyValue":9,"./PropertyValuePart":11,"./Selector":13,"./SelectorPart":14,"./SelectorSubPart":15,"./TokenStream":17,"./Tokens":18,"./Validation":19}],7:[function(require,module,exports){
-"use strict";
-
-/* exported Properties */
-
-var Properties = module.exports = {
-    __proto__: null,
-
-    //A
-    "align-items"                   : "normal | stretch | <baseline-position> | [ <overflow-position>? <self-position> ]",
-    "align-content"                 : "<align-content>",
-    "align-self"                    : "<align-self>",
-    "all"                           : "initial | inherit | unset",
-    "alignment-adjust"              : "auto | baseline | before-edge | text-before-edge | middle | central | after-edge | text-after-edge | ideographic | alphabetic | hanging | mathematical | <percentage> | <length>",
-    "alignment-baseline"            : "auto | baseline | use-script | before-edge | text-before-edge | after-edge | text-after-edge | central | middle | ideographic | alphabetic | hanging | mathematical",
-    "animation"                     : "[ <time> || <single-timing-function> || <time> || [ infinite | <number> ] || <single-animation-direction> || <single-animation-fill-mode> || [ running | paused ] || [ none | <ident> | <string> ] ]#",
-    "animation-delay"               : "<time>#",
-    "animation-direction"           : "<single-animation-direction>#",
-    "animation-duration"            : "<time>#",
-    "animation-fill-mode"           : "<single-animation-fill-mode>#",
-    "animation-iteration-count"     : "[ <number> | infinite ]#",
-    "animation-name"                : "[ none | <single-animation-name> ]#",
-    "animation-play-state"          : "[ running | paused ]#",
-    "animation-timing-function"     : "<single-timing-function>#",
-
-    "appearance"                    : "none | auto",
-    "-moz-appearance"               : "none | button | button-arrow-down | button-arrow-next | button-arrow-previous | button-arrow-up | button-bevel | button-focus | caret | checkbox | checkbox-container | checkbox-label | checkmenuitem | dualbutton | groupbox | listbox | listitem | menuarrow | menubar | menucheckbox | menuimage | menuitem | menuitemtext | menulist | menulist-button | menulist-text | menulist-textfield | menupopup | menuradio | menuseparator | meterbar | meterchunk | progressbar | progressbar-vertical | progresschunk | progresschunk-vertical | radio | radio-container | radio-label | radiomenuitem | range | range-thumb | resizer | resizerpanel | scale-horizontal | scalethumbend | scalethumb-horizontal | scalethumbstart | scalethumbtick | scalethumb-vertical | scale-vertical | scrollbarbutton-down | scrollbarbutton-left | scrollbarbutton-right | scrollbarbutton-up | scrollbarthumb-horizontal | scrollbarthumb-vertical | scrollbartrack-horizontal | scrollbartrack-vertical | searchfield | separator | sheet | spinner | spinner-downbutton | spinner-textfield | spinner-upbutton | splitter | statusbar | statusbarpanel | tab | tabpanel | tabpanels | tab-scroll-arrow-back | tab-scroll-arrow-forward | textfield | textfield-multiline | toolbar | toolbarbutton | toolbarbutton-dropdown | toolbargripper | toolbox | tooltip | treeheader | treeheadercell | treeheadersortarrow | treeitem | treeline | treetwisty | treetwistyopen | treeview | -moz-mac-unified-toolbar | -moz-win-borderless-glass | -moz-win-browsertabbar-toolbox | -moz-win-communicationstext | -moz-win-communications-toolbox | -moz-win-exclude-glass | -moz-win-glass | -moz-win-mediatext | -moz-win-media-toolbox | -moz-window-button-box | -moz-window-button-box-maximized | -moz-window-button-close | -moz-window-button-maximize | -moz-window-button-minimize | -moz-window-button-restore | -moz-window-frame-bottom | -moz-window-frame-left | -moz-window-frame-right | -moz-window-titlebar | -moz-window-titlebar-maximized",
-    "-ms-appearance"                : "none | icon | window | desktop | workspace | document | tooltip | dialog | button | push-button | hyperlink | radio | radio-button | checkbox | menu-item | tab | menu | menubar | pull-down-menu | pop-up-menu | list-menu | radio-group | checkbox-group | outline-tree | range | field | combo-box | signature | password | normal",
-    "-webkit-appearance"            : "none | button | button-bevel | caps-lock-indicator | caret | checkbox | default-button | listbox | listitem | media-fullscreen-button | media-mute-button | media-play-button | media-seek-back-button | media-seek-forward-button | media-slider | media-sliderthumb | menulist | menulist-button | menulist-text | menulist-textfield | push-button | radio | searchfield | searchfield-cancel-button | searchfield-decoration | searchfield-results-button | searchfield-results-decoration | slider-horizontal | slider-vertical | sliderthumb-horizontal | sliderthumb-vertical | square-button | textarea | textfield | scrollbarbutton-down | scrollbarbutton-left | scrollbarbutton-right | scrollbarbutton-up | scrollbargripper-horizontal | scrollbargripper-vertical | scrollbarthumb-horizontal | scrollbarthumb-vertical | scrollbartrack-horizontal | scrollbartrack-vertical",
-    "-o-appearance"                 : "none | window | desktop | workspace | document | tooltip | dialog | button | push-button | hyperlink | radio | radio-button | checkbox | menu-item | tab | menu | menubar | pull-down-menu | pop-up-menu | list-menu | radio-group | checkbox-group | outline-tree | range | field | combo-box | signature | password | normal",
-
-    "azimuth"                       : "<azimuth>",
-
-    //B
-    "backface-visibility"           : "visible | hidden",
-    "background"                    : "[ <bg-layer> , ]* [ <color> || <bg-layer> ]",
-    "background-attachment"         : "<attachment>#",
-    "background-blend-mode"         : "<blend-mode>",
-    "background-clip"               : "<box>#",
-    "background-color"              : "<color>",
-    "background-image"              : "<bg-image>#",
-    "background-origin"             : "<box>#",
-    "background-position"           : "<bg-position>",
-    "background-repeat"             : "<repeat-style>#",
-    "background-size"               : "<bg-size>#",
-    "baseline-shift"                : "baseline | sub | super | <percentage> | <length>",
-    "behavior"                      : 1,
-    "binding"                       : 1,
-    "bleed"                         : "<length>",
-    "bookmark-label"                : "<content> | <attr> | <string>",
-    "bookmark-level"                : "none | <integer>",
-    "bookmark-state"                : "open | closed",
-    "bookmark-target"               : "none | <uri> | <attr>",
-    "border"                        : "<border-width> || <border-style> || <color>",
-    "border-bottom"                 : "<border-width> || <border-style> || <color>",
-    "border-bottom-color"           : "<color>",
-    "border-bottom-left-radius"     :  "<x-one-radius>",
-    "border-bottom-right-radius"    :  "<x-one-radius>",
-    "border-bottom-style"           : "<border-style>",
-    "border-bottom-width"           : "<border-width>",
-    "border-collapse"               : "collapse | separate",
-    "border-color"                  : "<color>{1,4}",
-    "border-image"                  : "[ none | <image> ] || <border-image-slice> [ / <border-image-width> | / <border-image-width>? / <border-image-outset> ]? || <border-image-repeat>",
-    "border-image-outset"           : "<border-image-outset>",
-    "border-image-repeat"           : "<border-image-repeat>",
-    "border-image-slice"            : "<border-image-slice>",
-    "border-image-source"           : "<image> | none",
-    "border-image-width"            : "<border-image-width>",
-    "border-left"                   : "<border-width> || <border-style> || <color>",
-    "border-left-color"             : "<color>",
-    "border-left-style"             : "<border-style>",
-    "border-left-width"             : "<border-width>",
-    "border-radius"                 : "<border-radius>",
-    "border-right"                  : "<border-width> || <border-style> || <color>",
-    "border-right-color"            : "<color>",
-    "border-right-style"            : "<border-style>",
-    "border-right-width"            : "<border-width>",
-    "border-spacing"                : "<length>{1,2}",
-    "border-style"                  : "<border-style>{1,4}",
-    "border-top"                    : "<border-width> || <border-style> || <color>",
-    "border-top-color"              : "<color>",
-    "border-top-left-radius"        : "<x-one-radius>",
-    "border-top-right-radius"       : "<x-one-radius>",
-    "border-top-style"              : "<border-style>",
-    "border-top-width"              : "<border-width>",
-    "border-width"                  : "<border-width>{1,4}",
-    "bottom"                        : "<margin-width>",
-    "-moz-box-align"                : "start | end | center | baseline | stretch",
-    "-moz-box-decoration-break"     : "slice | clone",
-    "-moz-box-direction"            : "normal | reverse",
-    "-moz-box-flex"                 : "<number>",
-    "-moz-box-flex-group"           : "<integer>",
-    "-moz-box-lines"                : "single | multiple",
-    "-moz-box-ordinal-group"        : "<integer>",
-    "-moz-box-orient"               : "horizontal | vertical | inline-axis | block-axis",
-    "-moz-box-pack"                 : "start | end | center | justify",
-    "-o-box-decoration-break"       : "slice | clone",
-    "-webkit-box-align"             : "start | end | center | baseline | stretch",
-    "-webkit-box-decoration-break"  : "slice | clone",
-    "-webkit-box-direction"         : "normal | reverse",
-    "-webkit-box-flex"              : "<number>",
-    "-webkit-box-flex-group"        : "<integer>",
-    "-webkit-box-lines"             : "single | multiple",
-    "-webkit-box-ordinal-group"     : "<integer>",
-    "-webkit-box-orient"            : "horizontal | vertical | inline-axis | block-axis",
-    "-webkit-box-pack"              : "start | end | center | justify",
-    "box-decoration-break"          : "slice | clone",
-    "box-shadow"                    : "<box-shadow>",
-    "box-sizing"                    : "content-box | border-box",
-    "break-after"                   : "auto | always | avoid | left | right | page | column | avoid-page | avoid-column",
-    "break-before"                  : "auto | always | avoid | left | right | page | column | avoid-page | avoid-column",
-    "break-inside"                  : "auto | avoid | avoid-page | avoid-column",
-
-    //C
-    "caret-color"                   : "auto | <color>",
-    "caption-side"                  : "top | bottom",
-    "clear"                         : "none | right | left | both",
-    "clip"                          : "<shape> | auto",
-    "clip-path"                     : "<clip-source> | <clip-path> | none",
-    "clip-rule"                     : "nonzero | evenodd",
-    "color"                         : "<color>",
-    "color-interpolation"           : "auto | sRGB | linearRGB",
-    "color-interpolation-filters"   : "auto | sRGB | linearRGB",
-    "color-profile"                 : 1,
-    "color-rendering"               : "auto | optimizeSpeed | optimizeQuality",
-    "column-count"                  : "<integer> | auto",                      //https://www.w3.org/TR/css3-multicol/
-    "column-fill"                   : "auto | balance",
-    "column-gap"                    : "<column-gap>",
-    "column-rule"                   : "<border-width> || <border-style> || <color>",
-    "column-rule-color"             : "<color>",
-    "column-rule-style"             : "<border-style>",
-    "column-rule-width"             : "<border-width>",
-    "column-span"                   : "none | all",
-    "column-width"                  : "<length> | auto",
-    "columns"                       : 1,
-    "content"                       : 1,
-    "counter-increment"             : 1,
-    "counter-reset"                 : 1,
-    "crop"                          : "<shape> | auto",
-    "cue"                           : "cue-after | cue-before",
-    "cue-after"                     : 1,
-    "cue-before"                    : 1,
-    "cursor"                        : "[ <uri> [ <number> <number> ]? , ]* [ auto | default | none | context-menu | help | pointer | progress | wait | cell | crosshair | text | vertical-text | alias | copy | move | no-drop | not-allowed | grab | grabbing | e-resize | n-resize | ne-resize | nw-resize | s-resize | se-resize | sw-resize | w-resize | ew-resize | ns-resize | nesw-resize | nwse-resize | col-resize | row-resize | all-scroll | zoom-in | zoom-out ]",
-
-    //D
-    "direction"                     : "ltr | rtl",
-    "display"                       : "inline | block | list-item | inline-block | table | inline-table | table-row-group | table-header-group | table-footer-group | table-row | table-column-group | table-column | table-cell | table-caption | grid | inline-grid | run-in | ruby | ruby-base | ruby-text | ruby-base-container | ruby-text-container | contents | none | -moz-box | -moz-inline-block | -moz-inline-box | -moz-inline-grid | -moz-inline-stack | -moz-inline-table | -moz-grid | -moz-grid-group | -moz-grid-line | -moz-groupbox | -moz-deck | -moz-popup | -moz-stack | -moz-marker | -webkit-box | -webkit-inline-box | -ms-flexbox | -ms-inline-flexbox | flex | -webkit-flex | inline-flex | -webkit-inline-flex",
-    "dominant-baseline"             : "auto | use-script | no-change | reset-size | ideographic | alphabetic | hanging | mathematical | central | middle | text-after-edge | text-before-edge",
-    "drop-initial-after-adjust"     : "central | middle | after-edge | text-after-edge | ideographic | alphabetic | mathematical | <percentage> | <length>",
-    "drop-initial-after-align"      : "baseline | use-script | before-edge | text-before-edge | after-edge | text-after-edge | central | middle | ideographic | alphabetic | hanging | mathematical",
-    "drop-initial-before-adjust"    : "before-edge | text-before-edge | central | middle | hanging | mathematical | <percentage> | <length>",
-    "drop-initial-before-align"     : "caps-height | baseline | use-script | before-edge | text-before-edge | after-edge | text-after-edge | central | middle | ideographic | alphabetic | hanging | mathematical",
-    "drop-initial-size"             : "auto | line | <length> | <percentage>",
-    "drop-initial-value"            : "<integer>",
-
-    //E
-    "elevation"                     : "<angle> | below | level | above | higher | lower",
-    "empty-cells"                   : "show | hide",
-    "enable-background"             : 1,
-
-    //F
-    "fill"                          : "<paint>",
-    "fill-opacity"                  : "<opacity-value>",
-    "fill-rule"                     : "nonzero | evenodd",
-    "filter"                        : "<filter-function-list> | none",
-    "fit"                           : "fill | hidden | meet | slice",
-    "fit-position"                  : 1,
-    "flex"                          : "<flex-shorthand>",
-    "flex-basis"                    : "<width>",
-    "flex-direction"                : "row | row-reverse | column | column-reverse",
-    "flex-flow"                     : "<flex-direction> || <flex-wrap>",
-    "flex-grow"                     : "<number>",
-    "flex-shrink"                   : "<number>",
-    "flex-wrap"                     : "nowrap | wrap | wrap-reverse",
-    "-ms-flex-align"                : "start | end | center | stretch | baseline",
-    "-ms-flex-order"                : "<number>",
-    "-ms-flex-pack"                 : "start | end | center | justify",
-    "float"                         : "left | right | none",
-    "float-offset"                  : 1,
-    "flood-color"                   : 1,
-    "flood-opacity"                 : "<opacity-value>",
-    "font"                          : "<font-shorthand> | caption | icon | menu | message-box | small-caption | status-bar",
-    "font-family"                   : "<font-family>",
-    "font-feature-settings"         : "<feature-tag-value> | normal",
-    "font-kerning"                  : "auto | normal | none",
-    "font-size"                     : "<font-size>",
-    "font-size-adjust"              : "<number> | none",
-    "font-stretch"                  : "<font-stretch>",
-    "font-style"                    : "<font-style>",
-    "font-variant"                  : "<font-variant> | normal | none",
-    "font-variant-alternates"       : "<font-variant-alternates> | normal",
-    "font-variant-caps"             : "<font-variant-caps> | normal",
-    "font-variant-east-asian"       : "<font-variant-east-asian> | normal",
-    "font-variant-ligatures"        : "<font-variant-ligatures> | normal | none",
-    "font-variant-numeric"          : "<font-variant-numeric> | normal",
-    "font-variant-position"         : "normal | sub | super",
-    "font-weight"                   : "<font-weight>",
-
-    //G
-    "gap"                           : "<row-gap> <column-gap>?",
-    "glyph-orientation-horizontal"  : "<glyph-angle>",
-    "glyph-orientation-vertical"    : "auto | <glyph-angle>",
-    "grid"                          : "<grid-template> | <grid-template-rows> / [ auto-flow && dense? ] <grid-auto-columns>? | [ auto-flow && dense? ] <grid-auto-rows>? / <grid-template-columns>",
-    "grid-area"                     : "<grid-line> [ / <grid-line> ]{0,3}",
-    "grid-auto-columns"             : "<grid-auto-columns>",
-    "grid-auto-flow"                : "[ row | column ] || dense",
-    "grid-auto-rows"                : "<grid-auto-rows>",
-    "grid-column"                   : "<grid-line> [ / <grid-line> ]?",
-    "grid-column-start"             : "<grid-line>",
-    "grid-column-end"               : "<grid-line>",
-    "grid-row"                      : "<grid-line> [ / <grid-line> ]?",
-    "grid-row-start"                : "<grid-line>",
-    "grid-row-end"                  : "<grid-line>",
-    "grid-template"                 : "none | [ <grid-template-rows> / <grid-template-columns> ] | [ <line-names>? <string> <track-size>? <line-names>? ]+ [ / <explicit-track-list> ]?",
-    "grid-template-areas"           : "none | <string>+",
-    "grid-template-columns"         : "<grid-template-columns>",
-    "grid-template-rows"            : "<grid-template-rows>",
-    //G - deprecated aliases
-    "grid-row-gap"                  : "<row-gap>",
-    "grid-column-gap"               : "<column-gap>",
-    "grid-gap"                      : "<row-gap> <column-gap>?",
-
-    //H
-    "hanging-punctuation"           : 1,
-    "height"                        : "<margin-width> | <content-sizing>",
-    "hyphenate-after"               : "<integer> | auto",
-    "hyphenate-before"              : "<integer> | auto",
-    "hyphenate-character"           : "<string> | auto",
-    "hyphenate-lines"               : "no-limit | <integer>",
-    "hyphenate-resource"            : 1,
-    "hyphens"                       : "none | manual | auto",
-
-    //I
-    "icon"                          : 1,
-    "image-orientation"             : "angle | auto",
-    "image-rendering"               : "auto | optimizeSpeed | optimizeQuality",
-    "image-resolution"              : 1,
-    "ime-mode"                      : "auto | normal | active | inactive | disabled",
-    "inline-box-align"              : "last | <integer>",
-    "isolation"                     : "auto | isolate",
-
-    //J
-    "justify-content"               : "<justify-content>",
-    "justify-items"                 : "normal | stretch | <baseline-position> | [ <overflow-position>? <self-position> ] | [ legacy || [ left | right | center ] ]",
-    "justify-self"                  : "<justify-self>",
-
-    //K
-    "kerning"                       : "auto | <length>",
-
-    //L
-    "left"                          : "<margin-width>",
-    "letter-spacing"                : "<length> | normal",
-    "line-height"                   : "<line-height>",
-    "line-break"                    : "auto | loose | normal | strict",
-    "line-stacking"                 : 1,
-    "line-stacking-ruby"            : "exclude-ruby | include-ruby",
-    "line-stacking-shift"           : "consider-shifts | disregard-shifts",
-    "line-stacking-strategy"        : "inline-line-height | block-line-height | max-height | grid-height",
-    "list-style"                    : 1,
-    "list-style-image"              : "<uri> | none",
-    "list-style-position"           : "inside | outside",
-    "list-style-type"               : "disc | circle | square | decimal | decimal-leading-zero | lower-roman | upper-roman | lower-greek | lower-latin | upper-latin | armenian | georgian | lower-alpha | upper-alpha | none",
-
-    //M
-    "margin"                        : "<margin-width>{1,4}",
-    "margin-bottom"                 : "<margin-width>",
-    "margin-left"                   : "<margin-width>",
-    "margin-right"                  : "<margin-width>",
-    "margin-top"                    : "<margin-width>",
-    "mark"                          : 1,
-    "mark-after"                    : 1,
-    "mark-before"                   : 1,
-    "marker"                        : 1,
-    "marker-end"                    : 1,
-    "marker-mid"                    : 1,
-    "marker-start"                  : 1,
-    "marks"                         : 1,
-    "marquee-direction"             : 1,
-    "marquee-play-count"            : 1,
-    "marquee-speed"                 : 1,
-    "marquee-style"                 : 1,
-    "mask"                          : 1,
-    "max-height"                    : "<length> | <percentage> | <content-sizing> | none",
-    "max-width"                     : "<length> | <percentage> | <content-sizing> | none",
-    "min-height"                    : "<length> | <percentage> | <content-sizing> | contain-floats | -moz-contain-floats | -webkit-contain-floats",
-    "min-width"                     : "<length> | <percentage> | <content-sizing> | contain-floats | -moz-contain-floats | -webkit-contain-floats",
-    "mix-blend-mode"                : "<blend-mode>",
-    "move-to"                       : 1,
-
-    //N
-    "nav-down"                      : 1,
-    "nav-index"                     : 1,
-    "nav-left"                      : 1,
-    "nav-right"                     : 1,
-    "nav-up"                        : 1,
-
-    //O
-    "object-fit"                    : "fill | contain | cover | none | scale-down",
-    "object-position"               : "<position>",
-    "opacity"                       : "<opacity-value>",
-    "order"                         : "<integer>",
-    "orphans"                       : "<integer>",
-    "outline"                       : 1,
-    "outline-color"                 : "<color> | invert",
-    "outline-offset"                : 1,
-    "outline-style"                 : "<border-style>",
-    "outline-width"                 : "<border-width>",
-    "overflow"                      : "visible | hidden | scroll | auto",
-    "overflow-style"                : 1,
-    "overflow-wrap"                 : "normal | break-word",
-    "overflow-x"                    : 1,
-    "overflow-y"                    : 1,
-
-    //P
-    "padding"                       : "<padding-width>{1,4}",
-    "padding-bottom"                : "<padding-width>",
-    "padding-left"                  : "<padding-width>",
-    "padding-right"                 : "<padding-width>",
-    "padding-top"                   : "<padding-width>",
-    "page"                          : 1,
-    "page-break-after"              : "auto | always | avoid | left | right",
-    "page-break-before"             : "auto | always | avoid | left | right",
-    "page-break-inside"             : "auto | avoid",
-    "page-policy"                   : 1,
-    "pause"                         : 1,
-    "pause-after"                   : 1,
-    "pause-before"                  : 1,
-    "perspective"                   : "none | <length>",
-    "perspective-origin"            : "<position>",
-    "phonemes"                      : 1,
-    "pitch"                         : 1,
-    "pitch-range"                   : 1,
-    "place-content"                 : "<align-content> <justify-content>?",
-    "place-items"                   : "[ normal | stretch | <baseline-position> | <self-position> ] [ normal | stretch | <baseline-position> | <self-position> ]?",
-    "place-self"                    : "<align-self> <justify-self>?",
-    "play-during"                   : 1,
-    "pointer-events"                : "auto | none | visiblePainted | visibleFill | visibleStroke | visible | painted | fill | stroke | all",
-    "position"                      : "static | relative | absolute | fixed | sticky | -webkit-sticky",
-    "presentation-level"            : 1,
-    "punctuation-trim"              : 1,
-
-    //Q
-    "quotes"                        : 1,
-
-    //R
-    "rendering-intent"              : 1,
-    "resize"                        : 1,
-    "rest"                          : 1,
-    "rest-after"                    : 1,
-    "rest-before"                   : 1,
-    "richness"                      : 1,
-    "right"                         : "<margin-width>",
-    "rotate"                        : "none | <number>{3}? <angle>",
-    "rotation"                      : 1,
-    "rotation-point"                : 1,
-    "row-gap"                       : "<row-gap>",
-    "ruby-align"                    : 1,
-    "ruby-overhang"                 : 1,
-    "ruby-position"                 : 1,
-    "ruby-span"                     : 1,
-
-    //S
-    "scale"                         : "none | <number>{1,3}",
-    "shape-rendering"               : "auto | optimizeSpeed | crispEdges | geometricPrecision",
-    "size"                          : 1,
-    "speak"                         : "normal | none | spell-out",
-    "speak-header"                  : "once | always",
-    "speak-numeral"                 : "digits | continuous",
-    "speak-punctuation"             : "code | none",
-    "speech-rate"                   : 1,
-    "src"                           : 1,
-    "stop-color"                    : 1,
-    "stop-opacity"                  : "<opacity-value>",
-    "stress"                        : 1,
-    "string-set"                    : 1,
-    "stroke"                        : "<paint>",
-    "stroke-dasharray"              : "none | <dasharray>",
-    "stroke-dashoffset"             : "<percentage> | <length>",
-    "stroke-linecap"                : "butt | round | square",
-    "stroke-linejoin"               : "miter | round | bevel",
-    "stroke-miterlimit"             : "<miterlimit>",
-    "stroke-opacity"                : "<opacity-value>",
-    "stroke-width"                  : "<percentage> | <length>",
-
-    "table-layout"                  : "auto | fixed",
-    "tab-size"                      : "<integer> | <length>",
-    "target"                        : 1,
-    "target-name"                   : 1,
-    "target-new"                    : 1,
-    "target-position"               : 1,
-    "text-align"                    : "left | right | center | justify | match-parent | start | end",
-    "text-align-last"               : 1,
-    "text-anchor"                   : "start | middle | end",
-    "text-decoration"               : "<text-decoration-line> || <text-decoration-style> || <text-decoration-color>",
-    "text-decoration-color"         : "<text-decoration-color>",
-    "text-decoration-line"          : "<text-decoration-line>",
-    "text-decoration-skip"          : "none | [ objects || [ spaces | [ leading-spaces || trailing-spaces ] ] || edges || box-decoration ]",
-    "text-decoration-style"         : "<text-decoration-style>",
-    "text-emphasis"                 : 1,
-    "text-height"                   : 1,
-    "text-indent"                   : "<length> | <percentage>",
-    "text-justify"                  : "auto | none | inter-word | inter-ideograph | inter-cluster | distribute | kashida",
-    "text-outline"                  : 1,
-    "text-overflow"                 : "clip | ellipsis",
-    "text-rendering"                : "auto | optimizeSpeed | optimizeLegibility | geometricPrecision",
-    "text-shadow"                   : "none | [ [ <color> && <length>{2,3} ] | <length>{2,3} ]#",
-    "text-transform"                : "capitalize | uppercase | lowercase | none",
-    "text-wrap"                     : "normal | none | avoid",
-    "top"                           : "<margin-width>",
-    "touch-action"                  : "auto | none | pan-x | pan-y | pan-left | pan-right | pan-up | pan-down | manipulation",
-    "transform"                     : "none | <transform-function>+",
-    "transform-box"                 : "border-box | fill-box | view-box",
-    "transform-origin"              : "<transform-origin>",
-    "transform-style"               : "auto | flat | preserve-3d",
-    "transition"                    : "<transition>#",
-    "transition-delay"              : "<time>#",
-    "transition-duration"           : "<time>#",
-    "transition-property"           : "none | [ all | <ident> ]#",
-    "transition-timing-function"    : "<single-timing-function>#",
-    "translate"                     : "none | <length-percentage> [ <length-percentage> <length>? ]?",
-
-    //U
-    "unicode-range"                  : "<unicode-range>#",
-    "unicode-bidi"                  : "normal | embed | isolate | bidi-override | isolate-override | plaintext",
-    "user-modify"                   : "read-only | read-write | write-only",
-    "user-select"                   : "auto | text | none | contain | all",
-
-    //V
-    "vertical-align"                : "auto | use-script | baseline | sub | super | top | text-top | central | middle | bottom | text-bottom | <percentage> | <length>",
-    "visibility"                    : "visible | hidden | collapse",
-    "voice-balance"                 : 1,
-    "voice-duration"                : 1,
-    "voice-family"                  : 1,
-    "voice-pitch"                   : 1,
-    "voice-pitch-range"             : 1,
-    "voice-rate"                    : 1,
-    "voice-stress"                  : 1,
-    "voice-volume"                  : 1,
-    "volume"                        : 1,
-
-    //W
-    "white-space"                   : "normal | pre | nowrap | pre-wrap | pre-line | -pre-wrap | -o-pre-wrap | -moz-pre-wrap | -hp-pre-wrap",   // https://perishablepress.com/wrapping-content/
-    "white-space-collapse"          : 1,
-    "widows"                        : "<integer>",
-    "width"                         : "<length> | <percentage> | <content-sizing> | auto",
-    "will-change"                   : "<will-change>",
-    "word-break"                    : "normal | keep-all | break-all",
-    "word-spacing"                  : "<length> | normal",
-    "word-wrap"                     : "normal | break-word",
-    "writing-mode"                  : "horizontal-tb | vertical-rl | vertical-lr | lr-tb | rl-tb | tb-rl | bt-rl | tb-lr | bt-lr | lr-bt | rl-bt | lr | rl | tb",
-
-    //Z
-    "z-index"                       : "<integer> | auto",
-    "zoom"                          : "<number> | <percentage> | normal"
-};
-
-},{}],8:[function(require,module,exports){
-"use strict";
-
-module.exports = PropertyName;
-
-var SyntaxUnit = require("../util/SyntaxUnit");
-
-var Parser = require("./Parser");
-
-/**
- * Represents a selector combinator (whitespace, +, >).
- * @namespace parserlib.css
- * @class PropertyName
- * @extends parserlib.util.SyntaxUnit
- * @constructor
- * @param {String} text The text representation of the unit.
- * @param {String} hack The type of IE hack applied ("*", "_", or null).
- * @param {int} line The line of text on which the unit resides.
- * @param {int} col The column of text on which the unit resides.
- */
-function PropertyName(text, hack, line, col) {
-
-    SyntaxUnit.call(this, text, line, col, Parser.PROPERTY_NAME_TYPE);
-
-    /**
-     * The type of IE hack applied ("*", "_", or null).
-     * @type String
-     * @property hack
-     */
-    this.hack = hack;
-
-}
-
-PropertyName.prototype = new SyntaxUnit();
-PropertyName.prototype.constructor = PropertyName;
-PropertyName.prototype.toString = function() {
-    return (this.hack ? this.hack : "") + this.text;
-};
-
-},{"../util/SyntaxUnit":26,"./Parser":6}],9:[function(require,module,exports){
-"use strict";
-
-module.exports = PropertyValue;
-
-var SyntaxUnit = require("../util/SyntaxUnit");
-
-var Parser = require("./Parser");
-
-/**
- * Represents a single part of a CSS property value, meaning that it represents
- * just everything single part between ":" and ";". If there are multiple values
- * separated by commas, this type represents just one of the values.
- * @param {String[]} parts An array of value parts making up this value.
- * @param {int} line The line of text on which the unit resides.
- * @param {int} col The column of text on which the unit resides.
- * @namespace parserlib.css
- * @class PropertyValue
- * @extends parserlib.util.SyntaxUnit
- * @constructor
- */
-function PropertyValue(parts, line, col) {
-
-    SyntaxUnit.call(this, parts.join(" "), line, col, Parser.PROPERTY_VALUE_TYPE);
-
-    /**
-     * The parts that make up the selector.
-     * @type Array
-     * @property parts
-     */
-    this.parts = parts;
-
-}
-
-PropertyValue.prototype = new SyntaxUnit();
-PropertyValue.prototype.constructor = PropertyValue;
-
-
-},{"../util/SyntaxUnit":26,"./Parser":6}],10:[function(require,module,exports){
-"use strict";
-
-module.exports = PropertyValueIterator;
-
-/**
- * A utility class that allows for easy iteration over the various parts of a
- * property value.
- * @param {parserlib.css.PropertyValue} value The property value to iterate over.
- * @namespace parserlib.css
- * @class PropertyValueIterator
- * @constructor
- */
-function PropertyValueIterator(value) {
-
-    /**
-     * Iterator value
-     * @type int
-     * @property _i
-     * @private
-     */
-    this._i = 0;
-
-    /**
-     * The parts that make up the value.
-     * @type Array
-     * @property _parts
-     * @private
-     */
-    this._parts = value.parts;
-
-    /**
-     * Keeps track of bookmarks along the way.
-     * @type Array
-     * @property _marks
-     * @private
-     */
-    this._marks = [];
-
-    /**
-     * Holds the original property value.
-     * @type parserlib.css.PropertyValue
-     * @property value
-     */
-    this.value = value;
-
-}
-
-/**
- * Returns the total number of parts in the value.
- * @return {int} The total number of parts in the value.
- * @method count
- */
-PropertyValueIterator.prototype.count = function() {
-    return this._parts.length;
-};
-
-/**
- * Indicates if the iterator is positioned at the first item.
- * @return {Boolean} True if positioned at first item, false if not.
- * @method isFirst
- */
-PropertyValueIterator.prototype.isFirst = function() {
-    return this._i === 0;
-};
-
-/**
- * Indicates if there are more parts of the property value.
- * @return {Boolean} True if there are more parts, false if not.
- * @method hasNext
- */
-PropertyValueIterator.prototype.hasNext = function() {
-    return this._i < this._parts.length;
-};
-
-/**
- * Marks the current spot in the iteration so it can be restored to
- * later on.
- * @return {void}
- * @method mark
- */
-PropertyValueIterator.prototype.mark = function() {
-    this._marks.push(this._i);
-};
-
-/**
- * Returns the next part of the property value or null if there is no next
- * part. Does not move the internal counter forward.
- * @return {parserlib.css.PropertyValuePart} The next part of the property value or null if there is no next
- * part.
- * @method peek
- */
-PropertyValueIterator.prototype.peek = function(count) {
-    return this.hasNext() ? this._parts[this._i + (count || 0)] : null;
-};
-
-/**
- * Returns the next part of the property value or null if there is no next
- * part.
- * @return {parserlib.css.PropertyValuePart} The next part of the property value or null if there is no next
- * part.
- * @method next
- */
-PropertyValueIterator.prototype.next = function() {
-    return this.hasNext() ? this._parts[this._i++] : null;
-};
-
-/**
- * Returns the previous part of the property value or null if there is no
- * previous part.
- * @return {parserlib.css.PropertyValuePart} The previous part of the
- * property value or null if there is no previous part.
- * @method previous
- */
-PropertyValueIterator.prototype.previous = function() {
-    return this._i > 0 ? this._parts[--this._i] : null;
-};
-
-/**
- * Restores the last saved bookmark.
- * @return {void}
- * @method restore
- */
-PropertyValueIterator.prototype.restore = function() {
-    if (this._marks.length) {
-        this._i = this._marks.pop();
-    }
-};
-
-/**
- * Drops the last saved bookmark.
- * @return {void}
- * @method drop
- */
-PropertyValueIterator.prototype.drop = function() {
-    this._marks.pop();
-};
-
-},{}],11:[function(require,module,exports){
-"use strict";
-
-module.exports = PropertyValuePart;
-
-var SyntaxUnit = require("../util/SyntaxUnit");
-
-var Colors = require("./Colors");
-var Parser = require("./Parser");
-var Tokens = require("./Tokens");
-
-/**
- * Represents a single part of a CSS property value, meaning that it represents
- * just one part of the data between ":" and ";".
- * @param {String} text The text representation of the unit.
- * @param {int} line The line of text on which the unit resides.
- * @param {int} col The column of text on which the unit resides.
- * @namespace parserlib.css
- * @class PropertyValuePart
- * @extends parserlib.util.SyntaxUnit
- * @constructor
- */
-function PropertyValuePart(text, line, col, optionalHint) {
-    var hint = optionalHint || {};
-
-    SyntaxUnit.call(this, text, line, col, Parser.PROPERTY_VALUE_PART_TYPE);
-
-    /**
-     * Indicates the type of value unit.
-     * @type String
-     * @property type
-     */
-    this.type = "unknown";
-
-    //figure out what type of data it is
-
-    let temp;
-    const num = parseFloat(text);
-    const isNum = !isNaN(num);
-    const func = text.slice(0, Math.max(0, text.indexOf('('))).toLowerCase();
-
-    //it is a measurement?
-    if (isNum && /^([+-]?[\d.]+(?:e[+-]?\d+)?)([a-z]+)$/i.test(text)) {  //dimension
-        this.type = "dimension";
-        this.value = +RegExp.$1;
-        this.units = RegExp.$2;
-
-        //try to narrow down
-        switch (this.units.toLowerCase()) {
-
-            case "em":
-            case "rem":
-            case "ex":
-            case "px":
-            case "cm":
-            case "mm":
-            case "in":
-            case "pt":
-            case "pc":
-            case "ch":
-            case "vh":
-            case "vw":
-            case "vmax":
-            case "vmin":
-            case "fr":
-                this.type = "length";
-                break;
-
-            case "fr":
-                this.type = "grid";
-                break;
-
-            case "deg":
-            case "rad":
-            case "grad":
-            case "turn":
-                this.type = "angle";
-                break;
-
-            case "ms":
-            case "s":
-                this.type = "time";
-                break;
-
-            case "hz":
-            case "khz":
-                this.type = "frequency";
-                break;
-
-            case "dpi":
-            case "dpcm":
-                this.type = "resolution";
-                break;
-
-            //default
-
-        }
-
-    //percentage
-    } else if (isNum && text.endsWith('%') && !isNaN(Number(text.slice(0, -1)))) {
-        this.type = "percentage";
-        this.value = num;
-
-    //integer or number
-    } else if (isNum && !isNaN(Number(text))) {
-        this.type =  text.includes('.') ? "number" : "integer";
-        this.value = num;
-
-    //hexcolor
-    } else if (text[0] === '#' && /^#([a-f\d]{3}(?:[a-f\d](?:[a-f\d]{2}){0,2})?)\b/i.test(text)) {
-        this.type = "color";
-        temp = RegExp.$1;
-        if (temp.length <= 4) {
-            this.red    = parseInt(temp[0] + temp[0], 16);
-            this.green  = parseInt(temp[1] + temp[1], 16);
-            this.blue   = parseInt(temp[2] + temp[2], 16);
-            if (temp.length === 4) {
-                this.alpha = parseInt(temp[3]+temp[3], 16);
-            }
-        } else {
-            this.red    = parseInt(temp.substr(0, 2), 16);
-            this.green  = parseInt(temp.substr(2, 2), 16);
-            this.blue   = parseInt(temp.substr(4, 2), 16);
-            if (temp.length === 8) {
-                this.alpha = parseInt(temp.substr(6, 2), 16);
-            }
-        }
-
-    } else if ((func === 'rgb' || func === 'rgba') && /^rgba?\(\s*(.*?)\s*\)/i.test(text)) {
-        const str = RegExp.$1;
-        const commaSep = str.includes(',');
-        let [r, s1, g, s2, b, s3 = '', a] = commaSep ? str.split(/(\s*,\s*)/) : str.split(/(\s+(?:\/\s*)?|\s*\/\s*)/);
-        if (r && g && b &&
-            (commaSep || !s1.trim() && !s2.trim()) &&
-            (!s3.trim() && !a || s3.trim() === (commaSep ? ',' : '/') && a)
-        ) {
-            a = !a ? undefined : !a.endsWith('%') ? +a : +a.slice(0, -1) / 100 * 255;
-            if ((a === undefined || !isNaN(a)) && (
-                r.endsWith('%') && !isNaN(r = +r.slice(0, -1)) &&
-                g.endsWith('%') && !isNaN(g = +g.slice(0, -1)) &&
-                b.endsWith('%') && !isNaN(b = +b.slice(0, -1)) ||
-                !isNaN(r = +r) && !isNaN(g = +g) && !isNaN(b = +b)
-            )) {
-                this.type = 'color';
-                this.red = r;
-                this.green = g;
-                this.blue = b;
-                if (a !== undefined) this.alpha = a;
-            }
-        }
-    } else if ((func === 'hsl' || func === 'hsla') && /hsla?\(\s*(.*?)\s*\)/i.test(text)) {
-        const str = RegExp.$1;
-        const commaSep = str.includes(',');
-        let [h, s1, s, s2, l, s3 = '', a] = commaSep ? str.split(/(\s*,\s*)/) : str.split(/(\s+(?:\/\s*)?|\s*\/\s*)/);
-        if (h && s && l &&
-            (commaSep || !s1.trim() && !s2.trim()) &&
-            (!s3.trim() && !a || s3.trim() === (commaSep ? ',' : '/') && a)
-        ) {
-            a = !a ? undefined : !a.endsWith('%') ? +a : +a.slice(0, -1) / 100 * 255;
-            if ((a === undefined || !isNaN(a)) && (
-                s.endsWith('%') && !isNaN(s = +s.slice(0, -1)) &&
-                l.endsWith('%') && !isNaN(l = +l.slice(0, -1)) &&
-                /^([-+e\d.]+)(|deg|grad|rad|turn)$/.test(h) && !isNaN(h = +RegExp.$1)
-            )) {
-                this.type = 'color';
-                this.hue = h;
-                this.hueUnit = RegExp.$2;
-                this.saturation = s;
-                this.lightness = l;
-                if (a !== undefined) this.alpha = a;
-            }
-        }
-
-    } else if (func === 'url' && /^url\(("([^\\"]|\\.)*")\)/i.test(text)) { //URI
-        // generated by TokenStream.readURI, so always double-quoted.
-        this.type   = "uri";
-        this.uri    = PropertyValuePart.parseString(RegExp.$1);
-
-    } else if (func && /^([^(]+)\(/i.test(text)) {
-        this.type   = "function";
-        this.name   = RegExp.$1;
-        this.value  = text;
-
-    } else if (text[0] === '"' && /^"([^\n\r\f\\"]|\\\r\n|\\[^\r0-9a-f]|\\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?)*"/i.test(text)) {    //double-quoted string
-        this.type   = "string";
-        this.value  = PropertyValuePart.parseString(text);
-
-    } else if (text[0] === "'" && /^'([^\n\r\f\\']|\\\r\n|\\[^\r0-9a-f]|\\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?)*'/i.test(text)) {    //single-quoted string
-        this.type   = "string";
-        this.value  = PropertyValuePart.parseString(text);
-
-    } else if (!isNum && !func && Colors[text.toLowerCase()]) {  //named color
-        this.type   = "color";
-        temp        = Colors[text.toLowerCase()].substring(1);
-        this.red    = parseInt(temp.substring(0, 2), 16);
-        this.green  = parseInt(temp.substring(2, 4), 16);
-        this.blue   = parseInt(temp.substring(4, 6), 16);
-
-    } else if (/^[,\/]$/.test(text)) {
-        this.type   = "operator";
-        this.value  = text;
-
-    } else if (/^-?[a-z_\u00A0-\uFFFF][a-z0-9\-_\u00A0-\uFFFF]*$/i.test(text)) {
-        this.type   = "identifier";
-        this.value  = text;
-    }
-
-    // There can be ambiguity with escape sequences in identifiers, as
-    // well as with "color" parts which are also "identifiers", so record
-    // an explicit hint when the token generating this PropertyValuePart
-    // was an identifier.
-    this.wasIdent = Boolean(hint.ident);
-
-}
-
-PropertyValuePart.prototype = new SyntaxUnit();
-PropertyValuePart.prototype.constructor = PropertyValuePart;
-
-/**
- * Helper method to parse a CSS string.
- */
-PropertyValuePart.parseString = function(str) {
-    str = str.slice(1, -1); // Strip surrounding single/double quotes
-    var replacer = function(match, esc) {
-        if (/^(\n|\r\n|\r|\f)$/.test(esc)) {
-            return "";
-        }
-        var m = /^[0-9a-f]{1,6}/i.exec(esc);
-        if (m) {
-            var codePoint = parseInt(m[0], 16);
-            if (String.fromCodePoint) {
-                return String.fromCodePoint(codePoint);
-            } else {
-                // XXX No support for surrogates on old JavaScript engines.
-                return String.fromCharCode(codePoint);
-            }
-        }
-        return esc;
-    };
-    return str.replace(/\\(\r\n|[^\r0-9a-f]|[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?)/ig,
-                       replacer);
-};
-
-/**
- * Helper method to serialize a CSS string.
- */
-PropertyValuePart.serializeString = function(value) {
-    var replacer = function(c) {
-        if (c === "\"") {
-            return "\\" + c;
-        }
-        var cp = String.codePointAt ? c.codePointAt(0) :
-            // We only escape non-surrogate chars, so using charCodeAt
-            // is harmless here.
-            c.charCodeAt(0);
-        return "\\" + cp.toString(16) + " ";
-    };
-    return "\"" + value.replace(/["\r\n\f]/g, replacer) + "\"";
-};
-
-/**
- * Create a new syntax unit based solely on the given token.
- * Convenience method for creating a new syntax unit when
- * it represents a single token instead of multiple.
- * @param {Object} token The token object to represent.
- * @return {parserlib.css.PropertyValuePart} The object representing the token.
- * @static
- * @method fromToken
- */
-PropertyValuePart.fromToken = function(token) {
-    var part = new PropertyValuePart(token.value, token.startLine, token.startCol, {
-        // Tokens can have escaped characters that would fool the type
-        // identification in the PropertyValuePart constructor, so pass
-        // in a hint if this was an identifier.
-        ident: token.type === Tokens.IDENT
-    });
-    return part;
-};
-
-},{"../util/SyntaxUnit":26,"./Colors":1,"./Parser":6,"./Tokens":18}],12:[function(require,module,exports){
-"use strict";
-
-var Pseudos = module.exports = {
-    __proto__:       null,
-    ":first-letter": 1,
-    ":first-line":   1,
-    ":before":       1,
-    ":after":        1
-};
-
-Pseudos.ELEMENT = 1;
-Pseudos.CLASS = 2;
-
-Pseudos.isElement = function(pseudo) {
-    return pseudo.indexOf("::") === 0 || Pseudos[pseudo.toLowerCase()] === Pseudos.ELEMENT;
-};
-
-},{}],13:[function(require,module,exports){
-"use strict";
-
-module.exports = Selector;
-
-var SyntaxUnit = require("../util/SyntaxUnit");
-
-var Parser = require("./Parser");
-var Specificity = require("./Specificity");
-
-/**
- * Represents an entire single selector, including all parts but not
- * including multiple selectors (those separated by commas).
- * @namespace parserlib.css
- * @class Selector
- * @extends parserlib.util.SyntaxUnit
- * @constructor
- * @param {Array} parts Array of selectors parts making up this selector.
- * @param {int} line The line of text on which the unit resides.
- * @param {int} col The column of text on which the unit resides.
- */
-function Selector(parts, line, col) {
-
-    SyntaxUnit.call(this, parts.join(" "), line, col, Parser.SELECTOR_TYPE);
-
-    /**
-     * The parts that make up the selector.
-     * @type Array
-     * @property parts
-     */
-    this.parts = parts;
-
-    /**
-     * The specificity of the selector.
-     * @type parserlib.css.Specificity
-     * @property specificity
-     */
-    this.specificity = Specificity.calculate(this);
-
-}
-
-Selector.prototype = new SyntaxUnit();
-Selector.prototype.constructor = Selector;
-
-
-},{"../util/SyntaxUnit":26,"./Parser":6,"./Specificity":16}],14:[function(require,module,exports){
-"use strict";
-
-module.exports = SelectorPart;
-
-var SyntaxUnit = require("../util/SyntaxUnit");
-
-var Parser = require("./Parser");
-
-/**
- * Represents a single part of a selector string, meaning a single set of
- * element name and modifiers. This does not include combinators such as
- * spaces, +, >, etc.
- * @namespace parserlib.css
- * @class SelectorPart
- * @extends parserlib.util.SyntaxUnit
- * @constructor
- * @param {String} elementName The element name in the selector or null
- *      if there is no element name.
- * @param {Array} modifiers Array of individual modifiers for the element.
- *      May be empty if there are none.
- * @param {String} text The text representation of the unit.
- * @param {int} line The line of text on which the unit resides.
- * @param {int} col The column of text on which the unit resides.
- */
-function SelectorPart(elementName, modifiers, text, line, col) {
-
-    SyntaxUnit.call(this, text, line, col, Parser.SELECTOR_PART_TYPE);
-
-    /**
-     * The tag name of the element to which this part
-     * of the selector affects.
-     * @type String
-     * @property elementName
-     */
-    this.elementName = elementName;
-
-    /**
-     * The parts that come after the element name, such as class names, IDs,
-     * pseudo classes/elements, etc.
-     * @type Array
-     * @property modifiers
-     */
-    this.modifiers = modifiers;
-
-}
-
-SelectorPart.prototype = new SyntaxUnit();
-SelectorPart.prototype.constructor = SelectorPart;
-
-
-},{"../util/SyntaxUnit":26,"./Parser":6}],15:[function(require,module,exports){
-"use strict";
-
-module.exports = SelectorSubPart;
-
-var SyntaxUnit = require("../util/SyntaxUnit");
-
-var Parser = require("./Parser");
-
-/**
- * Represents a selector modifier string, meaning a class name, element name,
- * element ID, pseudo rule, etc.
- * @namespace parserlib.css
- * @class SelectorSubPart
- * @extends parserlib.util.SyntaxUnit
- * @constructor
- * @param {String} text The text representation of the unit.
- * @param {String} type The type of selector modifier.
- * @param {int} line The line of text on which the unit resides.
- * @param {int} col The column of text on which the unit resides.
- */
-function SelectorSubPart(text, type, line, col) {
-
-    SyntaxUnit.call(this, text, line, col, Parser.SELECTOR_SUB_PART_TYPE);
-
-    /**
-     * The type of modifier.
-     * @type String
-     * @property type
-     */
-    this.type = type;
-
-    /**
-     * Some subparts have arguments, this represents them.
-     * @type Array
-     * @property args
-     */
-    this.args = [];
-
-}
-
-SelectorSubPart.prototype = new SyntaxUnit();
-SelectorSubPart.prototype.constructor = SelectorSubPart;
-
-
-},{"../util/SyntaxUnit":26,"./Parser":6}],16:[function(require,module,exports){
-"use strict";
-
-module.exports = Specificity;
-
-var Pseudos = require("./Pseudos");
-var SelectorPart = require("./SelectorPart");
-
-/**
- * Represents a selector's specificity.
- * @namespace parserlib.css
- * @class Specificity
- * @constructor
- * @param {int} a Should be 1 for inline styles, zero for stylesheet styles
- * @param {int} b Number of ID selectors
- * @param {int} c Number of classes and pseudo classes
- * @param {int} d Number of element names and pseudo elements
- */
-function Specificity(a, b, c, d) {
-    this.a = a;
-    this.b = b;
-    this.c = c;
-    this.d = d;
-}
-
-Specificity.prototype = {
-    constructor: Specificity,
-
-    /**
-     * Compare this specificity to another.
-     * @param {Specificity} other The other specificity to compare to.
-     * @return {int} -1 if the other specificity is larger, 1 if smaller, 0 if equal.
-     * @method compare
-     */
-    compare: function(other) {
-        var comps = ["a", "b", "c", "d"],
-            i, len;
-
-        for (i=0, len=comps.length; i < len; i++) {
-            if (this[comps[i]] < other[comps[i]]) {
-                return -1;
-            } else if (this[comps[i]] > other[comps[i]]) {
-                return 1;
-            }
-        }
-
-        return 0;
-    },
-
-    /**
-     * Creates a numeric value for the specificity.
-     * @return {int} The numeric value for the specificity.
-     * @method valueOf
-     */
-    valueOf: function() {
-        return (this.a * 1000) + (this.b * 100) + (this.c * 10) + this.d;
-    },
-
-    /**
-     * Returns a string representation for specificity.
-     * @return {String} The string representation of specificity.
-     * @method toString
-     */
-    toString: function() {
-        return this.a + "," + this.b + "," + this.c + "," + this.d;
-    }
-
-};
-
-/**
- * Calculates the specificity of the given selector.
- * @param {parserlib.css.Selector} The selector to calculate specificity for.
- * @return {parserlib.css.Specificity} The specificity of the selector.
- * @static
- * @method calculate
- */
-Specificity.calculate = function(selector) {
-
-    var i, len,
-        part,
-        b=0, c=0, d=0;
-
-    function updateValues(part) {
-
-        var i, j, len, num,
-            elementName = part.elementName ? part.elementName.text : "",
-            modifier;
-
-        if (elementName && elementName.charAt(elementName.length-1) !== "*") {
-            d++;
-        }
-
-        for (i=0, len=part.modifiers.length; i < len; i++) {
-            modifier = part.modifiers[i];
-            switch (modifier.type) {
-                case "class":
-                case "attribute":
-                    c++;
-                    break;
-
-                case "id":
-                    b++;
-                    break;
-
-                case "pseudo":
-                    if (Pseudos.isElement(modifier.text)) {
-                        d++;
-                    } else {
-                        c++;
-                    }
-                    break;
-
-                case "not":
-                    for (j=0, num=modifier.args.length; j < num; j++) {
-                        updateValues(modifier.args[j]);
-                    }
-            }
-        }
-    }
-
-    for (i=0, len=selector.parts.length; i < len; i++) {
-        part = selector.parts[i];
-
-        if (part instanceof SelectorPart) {
-            updateValues(part);
-        }
-    }
-
-    return new Specificity(0, b, c, d);
-};
-
-},{"./Pseudos":12,"./SelectorPart":14}],17:[function(require,module,exports){
-"use strict";
-
-module.exports = TokenStream;
-
-var TokenStreamBase = require("../util/TokenStreamBase");
-
-var PropertyValuePart = require("./PropertyValuePart");
-var Tokens = require("./Tokens");
-
-var h = /^[0-9a-fA-F]$/,
-    nonascii = /^[\u00A0-\uFFFF]$/,
-    nl = /\n|\r\n|\r|\f/,
-    whitespace = /\u0009|\u000a|\u000c|\u000d|\u0020/;
-
-//-----------------------------------------------------------------------------
-// Helper functions
-//-----------------------------------------------------------------------------
-
-
-function isHexDigit(c) {
-    return c !== null && (c >= '0' && c <= '9' || c >= 'a' && c <= 'f' || c >= 'A' && c <= 'F');
-}
-
-function isDigit(c) {
-    return c !== null && c >= '0' && c <= '9';
-}
-
-function isWhitespace(c) {
-    return c !== null && (c === ' ' || c === '\t' || c === '\n' || c === '\f' || c === '\r');
-}
-
-function isNewLine(c) {
-    return c !== null && (c === '\n' || c === '\r\n' || c === '\r' || c === '\f');
-}
-
-function isNameStart(c) {
-    return c !== null && (
-        c >= 'a' && c <= 'z' ||
-        c >= 'A' && c <= 'Z' ||
-        c === '_' ||
-        c === '\\' ||
-        c >= '\u00A0' && c <= '\uFFFF');
-}
-
-function isNameChar(c) {
-    return c !== null && (c === '-' || c >= '0' && c <= '9' || isNameStart(c));
-}
-
-function isIdentStart(c) {
-    return c !== null && (c === '-' || isNameStart(c));
-}
-
-function mix(receiver, supplier) {
-    for (var prop in supplier) {
-        if (Object.prototype.hasOwnProperty.call(supplier, prop)) {
-            receiver[prop] = supplier[prop];
-        }
-    }
-    return receiver;
-}
-
-//-----------------------------------------------------------------------------
-// CSS Token Stream
-//-----------------------------------------------------------------------------
-
-
-/**
- * A token stream that produces CSS tokens.
- * @param {String|Reader} input The source of text to tokenize.
- * @constructor
- * @class TokenStream
- * @namespace parserlib.css
- */
-function TokenStream(input) {
-    TokenStreamBase.call(this, input, Tokens);
-}
-
-TokenStream.prototype = mix(new TokenStreamBase(), {
-
-    /**
-     * Overrides the TokenStreamBase method of the same name
-     * to produce CSS tokens.
-     * @return {Object} A token object representing the next token.
-     * @method _getToken
-     * @private
-     */
-    _getToken: function() {
-
-        var c,
-            reader = this._reader,
-            token   = null,
-            startLine   = reader._line,
-            startCol    = reader._col;
-
-        c = reader.read();
-
-
-        while (c) {
-            switch (c) {
-
-                /*
-                 * Potential tokens:
-                 * - S
-                 */
-                case ' ':
-                case '\n':
-                case '\r':
-                case '\t':
-                case '\f':
-                    token = this.whitespaceToken(c, startLine, startCol);
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - COMMENT
-                 * - SLASH
-                 * - CHAR
-                 */
-                case "/":
-
-                    if (reader.peek() === "*") {
-                        token = this.commentToken(c, startLine, startCol);
-                    } else {
-                        token = this.charToken(c, startLine, startCol);
-                    }
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - DASHMATCH
-                 * - INCLUDES
-                 * - PREFIXMATCH
-                 * - SUFFIXMATCH
-                 * - SUBSTRINGMATCH
-                 * - CHAR
-                 */
-                case "|":
-                case "~":
-                case "^":
-                case "$":
-                case "*":
-                    if (reader.peek() === "=") {
-                        token = this.comparisonToken(c, startLine, startCol);
-                    } else {
-                        token = this.charToken(c, startLine, startCol);
-                    }
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - STRING
-                 * - INVALID
-                 */
-                case "\"":
-                case "'":
-                    token = this.stringToken(c, startLine, startCol);
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - HASH
-                 * - CHAR
-                 */
-                case "#":
-                    if (isNameChar(reader.peek())) {
-                        token = this.hashToken(c, startLine, startCol);
-                    } else {
-                        token = this.charToken(c, startLine, startCol);
-                    }
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - DOT
-                 * - NUMBER
-                 * - DIMENSION
-                 * - PERCENTAGE
-                 */
-                case ".":
-                    if (isDigit(reader.peek())) {
-                        token = this.numberToken(c, startLine, startCol);
-                    } else {
-                        token = this.charToken(c, startLine, startCol);
-                    }
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - CDC
-                 * - MINUS
-                 * - NUMBER
-                 * - DIMENSION
-                 * - PERCENTAGE
-                 */
-                case "-":
-                    if (reader.peek() === "-") {  //could be closing HTML-style comment
-                        //or CSS variable
-                        if (/\w/.test(reader.peek(2))) {
-                            token = this.identOrFunctionToken(c, startLine, startCol);
-                        } else {
-                            token = this.htmlCommentEndToken(c, startLine, startCol);
-                        }
-                    } else if (isNameStart(reader.peek())) {
-                        token = this.identOrFunctionToken(c, startLine, startCol);
-                    } else {
-                        token = this.charToken(c, startLine, startCol);
-                    }
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - IMPORTANT_SYM
-                 * - CHAR
-                 */
-                case "!":
-                    token = this.importantToken(c, startLine, startCol);
-                    break;
-
-                /*
-                 * Any at-keyword or CHAR
-                 */
-                case "@":
-                    token = this.atRuleToken(c, startLine, startCol);
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - ANY
-                 * - NOT
-                 * - CHAR
-                 */
-                case ":":
-                    token = this.notOrAnyToken(c, startLine, startCol);
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - CDO
-                 * - CHAR
-                 */
-                case "<":
-                    token = this.htmlCommentStartToken(c, startLine, startCol);
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - IDENT
-                 * - CHAR
-                 */
-                case "\\":
-                    if (/[^\r\n\f]/.test(reader.peek())) {
-                        token = this.identOrFunctionToken(this.readEscape(c, true), startLine, startCol);
-                    } else {
-                        token = this.charToken(c, startLine, startCol);
-                    }
-                    break;
-
-                /*
-                 * Potential tokens:
-                 * - UNICODE_RANGE
-                 * - URL
-                 * - CHAR
-                 */
-                case "U":
-                case "u":
-                    if (reader.peek() === "+") {
-                        token = this.unicodeRangeToken(c, startLine, startCol);
-                        break;
-                    }
-                    /* falls through */
-                default:
-
-                    /*
-                     * Potential tokens:
-                     * - NUMBER
-                     * - DIMENSION
-                     * - LENGTH
-                     * - FREQ
-                     * - TIME
-                     * - EMS
-                     * - EXS
-                     * - ANGLE
-                     */
-                    if (isDigit(c)) {
-                        token = this.numberToken(c, startLine, startCol);
-                    } else
-
-                    /*
-                     * Potential tokens:
-                     * - IDENT
-                     */
-                    if (isIdentStart(c)) {
-                        token = this.identOrFunctionToken(c, startLine, startCol);
-                    } else {
-                       /*
-                        * Potential tokens:
-                        * - CHAR
-                        * - PLUS
-                        */
-                        token = this.charToken(c, startLine, startCol);
-                    }
-
-            }
-
-            //make sure this token is wanted
-            //TODO: check channel
-            break;
-        }
-
-        if (!token && c === null) {
-            token = this.createToken(Tokens.EOF, null, startLine, startCol);
-        }
-
-        return token;
-    },
-
-    //-------------------------------------------------------------------------
-    // Methods to create tokens
-    //-------------------------------------------------------------------------
-
-    /**
-     * Produces a token based on available data and the current
-     * reader position information. This method is called by other
-     * private methods to create tokens and is never called directly.
-     * @param {int} tt The token type.
-     * @param {String} value The text value of the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @param {Object} options (Optional) Specifies a channel property
-     *      to indicate that a different channel should be scanned
-     *      and/or a hide property indicating that the token should
-     *      be hidden.
-     * @return {Object} A token object.
-     * @method createToken
-     */
-    createToken: function(tt, value, startLine, startCol, options) {
-        var reader = this._reader;
-        options = options || {};
-
-        return {
-            value:      value,
-            type:       tt,
-            channel:    options.channel,
-            endChar:    options.endChar,
-            hide:       options.hide || false,
-            startLine:  startLine,
-            startCol:   startCol,
-            endLine:    reader.getLine(),
-            endCol:     reader.getCol()
-        };
-    },
-
-    //-------------------------------------------------------------------------
-    // Methods to create specific tokens
-    //-------------------------------------------------------------------------
-
-    /**
-     * Produces a token for any at-rule. If the at-rule is unknown, then
-     * the token is for a single "@" character.
-     * @param {String} first The first character for the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method atRuleToken
-     */
-    atRuleToken: function(first, startLine, startCol) {
-        var rule    = first,
-            reader  = this._reader,
-            tt      = Tokens.CHAR,
-            ident;
-
-        /*
-         * First, mark where we are. There are only four @ rules,
-         * so anything else is really just an invalid token.
-         * Basically, if this doesn't match one of the known @
-         * rules, just return '@' as an unknown token and allow
-         * parsing to continue after that point.
-         */
-        reader.mark();
-
-        //try to find the at-keyword
-        ident = this.readName();
-        rule = first + ident;
-        tt = Tokens.type(rule.toLowerCase());
-
-        //if it's not valid, use the first character only and reset the reader
-        if (tt === Tokens.CHAR || tt === Tokens.UNKNOWN) {
-            if (rule.length > 1) {
-                tt = Tokens.UNKNOWN_SYM;
-            } else {
-                tt = Tokens.CHAR;
-                rule = first;
-                reader.reset();
-            }
-        }
-
-        return this.createToken(tt, rule, startLine, startCol);
-    },
-
-    /**
-     * Produces a character token based on the given character
-     * and location in the stream. If there's a special (non-standard)
-     * token name, this is used; otherwise CHAR is used.
-     * @param {String} c The character for the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method charToken
-     */
-    charToken: function(c, startLine, startCol) {
-        var tt = Tokens.type(c);
-        var opts = {};
-
-        if (tt === -1) {
-            tt = Tokens.CHAR;
-        } else {
-            opts.endChar = Tokens[tt].endChar;
-        }
-
-        return this.createToken(tt, c, startLine, startCol, opts);
-    },
-
-    /**
-     * Produces a character token based on the given character
-     * and location in the stream. If there's a special (non-standard)
-     * token name, this is used; otherwise CHAR is used.
-     * @param {String} first The first character for the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method commentToken
-     */
-    commentToken: function(first, startLine, startCol) {
-        var comment = this.readComment(first);
-
-        return this.createToken(Tokens.COMMENT, comment, startLine, startCol);
-    },
-
-    /**
-     * Produces a comparison token based on the given character
-     * and location in the stream. The next character must be
-     * read and is already known to be an equals sign.
-     * @param {String} c The character for the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method comparisonToken
-     */
-    comparisonToken: function(c, startLine, startCol) {
-        var reader  = this._reader,
-            comparison  = c + reader.read(),
-            tt      = Tokens.type(comparison) || Tokens.CHAR;
-
-        return this.createToken(tt, comparison, startLine, startCol);
-    },
-
-    /**
-     * Produces a hash token based on the specified information. The
-     * first character provided is the pound sign (#) and then this
-     * method reads a name afterward.
-     * @param {String} first The first character (#) in the hash name.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method hashToken
-     */
-    hashToken: function(first, startLine, startCol) {
-        var name    = this.readName(first);
-
-        return this.createToken(Tokens.HASH, name, startLine, startCol);
-    },
-
-    /**
-     * Produces a CDO or CHAR token based on the specified information. The
-     * first character is provided and the rest is read by the function to determine
-     * the correct token to create.
-     * @param {String} first The first character in the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method htmlCommentStartToken
-     */
-    htmlCommentStartToken: function(first, startLine, startCol) {
-        var reader      = this._reader,
-            text        = first;
-
-        reader.mark();
-        text += reader.readCount(3);
-
-        if (text === "<!--") {
-            return this.createToken(Tokens.CDO, text, startLine, startCol);
-        } else {
-            reader.reset();
-            return this.charToken(first, startLine, startCol);
-        }
-    },
-
-    /**
-     * Produces a CDC or CHAR token based on the specified information. The
-     * first character is provided and the rest is read by the function to determine
-     * the correct token to create.
-     * @param {String} first The first character in the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method htmlCommentEndToken
-     */
-    htmlCommentEndToken: function(first, startLine, startCol) {
-        var reader      = this._reader,
-            text        = first;
-
-        reader.mark();
-        text += reader.readCount(2);
-
-        if (text === "-->") {
-            return this.createToken(Tokens.CDC, text, startLine, startCol);
-        } else {
-            reader.reset();
-            return this.charToken(first, startLine, startCol);
-        }
-    },
-
-    /**
-     * Produces an IDENT or FUNCTION token based on the specified information. The
-     * first character is provided and the rest is read by the function to determine
-     * the correct token to create.
-     * @param {String} first The first character in the identifier.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method identOrFunctionToken
-     */
-    identOrFunctionToken: function(first, startLine, startCol) {
-        var reader  = this._reader,
-            ident   = this.readName(first),
-            tt      = Tokens.IDENT,
-            uriFns  = ["url(", "url-prefix(", "domain("],
-            uri;
-
-        //if there's a left paren immediately after, it's a URI or function
-        if (reader.peek() === "(") {
-            ident += reader.read();
-            if (uriFns.indexOf(ident.toLowerCase()) > -1) {
-                reader.mark();
-                uri = this.readURI(ident);
-                if (uri === null) {
-                    //didn't find a valid URL or there's no closing paren
-                    reader.reset();
-                    tt = Tokens.FUNCTION;
-                } else {
-                    tt = Tokens.URI;
-                    ident = uri;
-                }
-            } else {
-                tt = Tokens.FUNCTION;
-            }
-        } else if (reader.peek() === ":") {  //might be an IE function
-
-            //IE-specific functions always being with progid:
-            if (ident.toLowerCase() === "progid") {
-                ident += reader.readTo("(");
-                tt = Tokens.IE_FUNCTION;
-            }
-        }
-
-        return this.createToken(tt, ident, startLine, startCol);
-    },
-
-    /**
-     * Produces an IMPORTANT_SYM or CHAR token based on the specified information. The
-     * first character is provided and the rest is read by the function to determine
-     * the correct token to create.
-     * @param {String} first The first character in the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method importantToken
-     */
-    importantToken: function(first, startLine, startCol) {
-        var reader      = this._reader,
-            important   = first,
-            tt          = Tokens.CHAR,
-            temp,
-            c;
-
-        reader.mark();
-        c = reader.read();
-
-        while (c) {
-
-            //there can be a comment in here
-            if (c === "/") {
-
-                //if the next character isn't a star, then this isn't a valid !important token
-                if (reader.peek() !== "*") {
-                    break;
-                } else {
-                    temp = this.readComment(c);
-                    if (temp === "") {    //broken!
-                        break;
-                    }
-                }
-            } else if (isWhitespace(c)) {
-                important += c + this.readWhitespace();
-            } else if (/i/i.test(c)) {
-                temp = reader.readCount(8);
-                if (/mportant/i.test(temp)) {
-                    important += c + temp;
-                    tt = Tokens.IMPORTANT_SYM;
-
-                }
-                break;  //we're done
-            } else {
-                break;
-            }
-
-            c = reader.read();
-        }
-
-        if (tt === Tokens.CHAR) {
-            reader.reset();
-            return this.charToken(first, startLine, startCol);
-        } else {
-            return this.createToken(tt, important, startLine, startCol);
-        }
-
-
-    },
-
-    /**
-     * Produces a NOT or ANY or CHAR token based on the specified information. The
-     * first character is provided and the rest is read by the function to determine
-     * the correct token to create.
-     * @param {String} first The first character in the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method notToken
-     */
-    notOrAnyToken: function(first, startLine, startCol) {
-        var reader      = this._reader;
-        var func = reader.readMatch(/not\(|(-(moz|webkit)-)?any\(/iy);
-        if (func) {
-            return this.createToken(func[1] === 'n' || func[1] === 'N' ? Tokens.NOT : Tokens.ANY,
-                first + func, startLine, startCol);
-        }
-        return this.charToken(first, startLine, startCol);
-    },
-
-    /**
-     * Produces a number token based on the given character
-     * and location in the stream. This may return a token of
-     * NUMBER, EMS, EXS, LENGTH, ANGLE, TIME, FREQ, DIMENSION,
-     * or PERCENTAGE.
-     * @param {String} first The first character for the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method numberToken
-     */
-    numberToken: function(first, startLine, startCol) {
-        var reader  = this._reader,
-            value   = this.readNumber(first),
-            ident,
-            tt      = Tokens.NUMBER,
-            c       = reader.peek();
-
-        if (isIdentStart(c)) {
-            ident = this.readName(reader.read());
-            value += ident;
-
-            if (/^em$|^ex$|^px$|^gd$|^rem$|^vw$|^vh$|^vmax$|^vmin$|^ch$|^cm$|^mm$|^in$|^pt$|^pc$/i.test(ident)) {
-                tt = Tokens.LENGTH;
-            } else if (/^deg|^rad$|^grad$|^turn$/i.test(ident)) {
-                tt = Tokens.ANGLE;
-            } else if (/^ms$|^s$/i.test(ident)) {
-                tt = Tokens.TIME;
-            } else if (/^hz$|^khz$/i.test(ident)) {
-                tt = Tokens.FREQ;
-            } else if (/^dpi$|^dpcm$/i.test(ident)) {
-                tt = Tokens.RESOLUTION;
-            } else {
-                tt = Tokens.DIMENSION;
-            }
-
-        } else if (c === "%") {
-            value += reader.read();
-            tt = Tokens.PERCENTAGE;
-        }
-
-        return this.createToken(tt, value, startLine, startCol);
-    },
-
-    /**
-     * Produces a string token based on the given character
-     * and location in the stream. Since strings may be indicated
-     * by single or double quotes, a failure to match starting
-     * and ending quotes results in an INVALID token being generated.
-     * The first character in the string is passed in and then
-     * the rest are read up to and including the final quotation mark.
-     * @param {String} first The first character in the string.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method stringToken
-     */
-    stringToken: function(first, startLine, startCol) {
-        var delim   = first,
-            string  = first,
-            reader  = this._reader,
-            tt      = Tokens.STRING,
-            c       = reader.read(),
-            i;
-
-        while (c) {
-            string += c;
-
-            if (c === "\\") {
-                c = reader.read();
-                if (c === null) {
-                    break; // premature EOF after backslash
-                } else if (/[^\r\n\f0-9a-f]/i.test(c)) {
-                    // single-character escape
-                    string += c;
-                } else {
-                    // read up to six hex digits
-                    for (i=0; isHexDigit(c) && i<6; i++) {
-                        string += c;
-                        c = reader.read();
-                    }
-                    // swallow trailing newline or space
-                    if (c === "\r" && reader.peek() === "\n") {
-                        string += c;
-                        c = reader.read();
-                    }
-                    if (isWhitespace(c)) {
-                        string += c;
-                    } else {
-                        // This character is null or not part of the escape;
-                        // jump back to the top to process it.
-                        continue;
-                    }
-                }
-            } else if (c === delim) {
-                break; // delimiter found.
-            } else if (isNewLine(reader.peek())) {
-                // newline without an escapement: it's an invalid string
-                tt = Tokens.INVALID;
-                break;
-            }
-            c = reader.read();
-        }
-
-        //if c is null, that means we're out of input and the string was never closed
-        if (c === null) {
-            tt = Tokens.INVALID;
-        }
-
-        return this.createToken(tt, string, startLine, startCol);
-    },
-
-    unicodeRangeToken: function(first, startLine, startCol) {
-        var reader  = this._reader,
-            value   = first,
-            temp,
-            tt      = Tokens.CHAR;
-
-        //then it should be a unicode range
-        if (reader.peek() === "+") {
-            reader.mark();
-            value += reader.read();
-            value += this.readUnicodeRangePart(true);
-
-            //ensure there's an actual unicode range here
-            if (value.length === 2) {
-                reader.reset();
-            } else {
-
-                tt = Tokens.UNICODE_RANGE;
-
-                //if there's a ? in the first part, there can't be a second part
-                if (value.indexOf("?") === -1) {
-
-                    if (reader.peek() === "-") {
-                        reader.mark();
-                        temp = reader.read();
-                        temp += this.readUnicodeRangePart(false);
-
-                        //if there's not another value, back up and just take the first
-                        if (temp.length === 1) {
-                            reader.reset();
-                        } else {
-                            value += temp;
-                        }
-                    }
-
-                }
-            }
-        }
-
-        return this.createToken(tt, value, startLine, startCol);
-    },
-
-    /**
-     * Produces a S token based on the specified information. Since whitespace
-     * may have multiple characters, this consumes all whitespace characters
-     * into a single token.
-     * @param {String} first The first character in the token.
-     * @param {int} startLine The beginning line for the character.
-     * @param {int} startCol The beginning column for the character.
-     * @return {Object} A token object.
-     * @method whitespaceToken
-     */
-    whitespaceToken: function(first, startLine, startCol) {
-        var value   = first + this.readWhitespace();
-        return this.createToken(Tokens.S, value, startLine, startCol);
-    },
-
-
-    //-------------------------------------------------------------------------
-    // Methods to read values from the string stream
-    //-------------------------------------------------------------------------
-
-    readUnicodeRangePart: function(allowQuestionMark) {
-        var reader  = this._reader,
-            part = "",
-            c       = reader.peek();
-
-        //first read hex digits
-        while (isHexDigit(c) && part.length < 6) {
-            reader.read();
-            part += c;
-            c = reader.peek();
-        }
-
-        //then read question marks if allowed
-        if (allowQuestionMark) {
-            while (c === "?" && part.length < 6) {
-                reader.read();
-                part += c;
-                c = reader.peek();
-            }
-        }
-
-        //there can't be any other characters after this point
-
-        return part;
-    },
-
-    readWhitespace: function() {
-        return this._reader.readMatch(/\s*/);
-    },
-
-    readNumber: function(first) {
-        const tail = this._reader.readMatch(
-            first === "." ? /\d+(e[+-]?\d+)?/y :
-                /(\d*\.\d+|\d+\.?\d*)(e[+-]?\d+)?/y);
-        return first + (tail || '');
-    },
-
-    // returns null w/o resetting reader if string is invalid.
-    readString: function() {
-        var token = this.stringToken(this._reader.read(), 0, 0);
-        return token.type === Tokens.INVALID ? null : token.value;
-    },
-
-    // returns null w/o resetting reader if URI is invalid.
-    readURI: function(first) {
-        var reader  = this._reader,
-            uri     = first,
-            inner   = "",
-            c       = reader.peek();
-
-        //skip whitespace before
-        while (c && isWhitespace(c)) {
-            reader.read();
-            c = reader.peek();
-        }
-
-        //it's a string
-        if (c === "'" || c === "\"") {
-            inner = this.readString();
-            if (inner !== null) {
-                inner = PropertyValuePart.parseString(inner);
-            }
-        } else {
-            inner = this.readUnquotedURL();
-        }
-
-        c = reader.peek();
-
-        //skip whitespace after
-        while (c && isWhitespace(c)) {
-            reader.read();
-            c = reader.peek();
-        }
-
-        //if there was no inner value or the next character isn't closing paren, it's not a URI
-        if (inner === null || c !== ")") {
-            uri = null;
-        } else {
-            // Ensure argument to URL is always double-quoted
-            // (This simplifies later processing in PropertyValuePart.)
-            uri += PropertyValuePart.serializeString(inner) + reader.read();
-        }
-
-        return uri;
-    },
-    // This method never fails, although it may return an empty string.
-    readUnquotedURL: function(first) {
-        var reader  = this._reader,
-            url     = first || "",
-            c;
-
-        for (c = reader.peek(); c; c = reader.peek()) {
-            // Note that the grammar at
-            // https://www.w3.org/TR/CSS2/grammar.html#scanner
-            // incorrectly includes the backslash character in the
-            // `url` production, although it is correctly omitted in
-            // the `baduri1` production.
-            if (nonascii.test(c) || /^[\-!#$%&*-\[\]-~]$/.test(c)) {
-                url += c;
-                reader.read();
-            } else if (c === "\\") {
-                if (/^[^\r\n\f]$/.test(reader.peek(2))) {
-                    url += this.readEscape(reader.read(), true);
-                } else {
-                    break; // bad escape sequence.
-                }
-            } else {
-                break; // bad character
-            }
-        }
-
-        return url;
-    },
-
-    readName: function(first) {
-        var reader  = this._reader,
-            ident   = [first || ''];
-
-        do {
-            var chunk = reader.readMatch(/[-_\da-zA-Z\u00A0-\uFFFF]*/y);
-            ident.push(chunk)
-            reader.mark();
-            var c = reader.read();
-            if (c === "\\" && /^[^\r\n\f]$/.test(reader.peek())) {
-                ident.push(this.readEscape(c, true));
-            } else {
-                reader.reset();
-                break;
-            }
-        } while (true);
-
-        return ident.length > 2 ? ident.join('') : ident.length > 1 ? ident[0] + ident[1] : ident[0];
-    },
-
-    readEscape: function(first, unescape) {
-        var reader  = this._reader,
-            cssEscape = first || "",
-            i       = 0,
-            c       = reader.peek();
-
-        if (isHexDigit(c)) {
-            do {
-                cssEscape += reader.read();
-                c = reader.peek();
-            } while (c && isHexDigit(c) && ++i < 6);
-        }
-
-        if (cssEscape.length === 1) {
-            if (/^[^\r\n\f0-9a-f]$/.test(c)) {
-                reader.read();
-                if (unescape) {
-                    return c;
-                }
-            } else {
-                // We should never get here (readName won't call readEscape
-                // if the escape sequence is bad).
-                throw new Error("Bad escape sequence.");
-            }
-        } else if (c === "\r") {
-            reader.read();
-            if (reader.peek() === "\n") {
-                c += reader.read();
-            }
-        } else if (/^[ \t\n\f]$/.test(c)) {
-            reader.read();
-        } else {
-            c = "";
-        }
-
-        if (unescape) {
-            var cp = parseInt(cssEscape.slice(first.length), 16);
-            return String.fromCodePoint ? String.fromCodePoint(cp) :
-                String.fromCharCode(cp);
-        }
-        return cssEscape + c;
-    },
-
-    readComment: function(first) {
-        return first +
-            this._reader.readCount(first ? 1 : 2) +
-            this._reader.readMatch(/([^*]|\*(?!\/))*(\*\/|$)/y);
-    }
-});
-
-},{"../util/TokenStreamBase":27,"./PropertyValuePart":11,"./Tokens":18}],18:[function(require,module,exports){
-"use strict";
-
-var Tokens = module.exports = [
-
-    /*
-     * The following token names are defined in CSS3 Grammar: https://www.w3.org/TR/css3-syntax/#lexical
-     */
-
-    // HTML-style comments
-    { name: "CDO" },
-    { name: "CDC" },
-
-    // ignorables
-    { name: "S", whitespace: true/*, channel: "ws"*/ },
-    { name: "COMMENT", whitespace: true, comment: true, hide: true/*, channel: "comment"*/ },
-
-    // attribute equality
-    { name: "INCLUDES", text: "~=" },
-    { name: "DASHMATCH", text: "|=" },
-    { name: "PREFIXMATCH", text: "^=" },
-    { name: "SUFFIXMATCH", text: "$=" },
-    { name: "SUBSTRINGMATCH", text: "*=" },
-
-    // identifier types
-    { name: "STRING" },
-    { name: "IDENT" },
-    { name: "HASH" },
-
-    // at-keywords
-    { name: "IMPORT_SYM", text: "@import" },
-    { name: "PAGE_SYM", text: "@page" },
-    { name: "MEDIA_SYM", text: "@media" },
-    { name: "FONT_FACE_SYM", text: "@font-face" },
-    { name: "CHARSET_SYM", text: "@charset" },
-    { name: "NAMESPACE_SYM", text: "@namespace" },
-    { name: "SUPPORTS_SYM", text: "@supports" },
-    { name: "VIEWPORT_SYM", text: ["@viewport", "@-ms-viewport", "@-o-viewport"] },
-    { name: "DOCUMENT_SYM", text: ["@document", "@-moz-document"] },
-    { name: "UNKNOWN_SYM" },
-    //{ name: "ATKEYWORD"},
-
-    // CSS3 animations
-    { name: "KEYFRAMES_SYM", text: [ "@keyframes", "@-webkit-keyframes", "@-moz-keyframes", "@-o-keyframes" ] },
-
-    // important symbol
-    { name: "IMPORTANT_SYM" },
-
-    // measurements
-    { name: "LENGTH" },
-    { name: "ANGLE" },
-    { name: "TIME" },
-    { name: "FREQ" },
-    { name: "DIMENSION" },
-    { name: "PERCENTAGE" },
-    { name: "NUMBER" },
-
-    // functions
-    { name: "URI" },
-    { name: "FUNCTION" },
-
-    // Unicode ranges
-    { name: "UNICODE_RANGE" },
-
-    /*
-     * The following token names are defined in CSS3 Selectors: https://www.w3.org/TR/css3-selectors/#selector-syntax
-     */
-
-    // invalid string
-    { name: "INVALID" },
-
-    // combinators
-    { name: "PLUS", text: "+" },
-    { name: "GREATER", text: ">" },
-    { name: "COMMA", text: "," },
-    { name: "TILDE", text: "~" },
-
-    // modifier
-    { name: "NOT" },
-    { name: "ANY", text: ["any", "-webkit-any", "-moz-any"] },
-
-    /*
-     * Defined in CSS3 Paged Media
-     */
-    { name: "TOPLEFTCORNER_SYM", text: "@top-left-corner" },
-    { name: "TOPLEFT_SYM", text: "@top-left" },
-    { name: "TOPCENTER_SYM", text: "@top-center" },
-    { name: "TOPRIGHT_SYM", text: "@top-right" },
-    { name: "TOPRIGHTCORNER_SYM", text: "@top-right-corner" },
-    { name: "BOTTOMLEFTCORNER_SYM", text: "@bottom-left-corner" },
-    { name: "BOTTOMLEFT_SYM", text: "@bottom-left" },
-    { name: "BOTTOMCENTER_SYM", text: "@bottom-center" },
-    { name: "BOTTOMRIGHT_SYM", text: "@bottom-right" },
-    { name: "BOTTOMRIGHTCORNER_SYM", text: "@bottom-right-corner" },
-    { name: "LEFTTOP_SYM", text: "@left-top" },
-    { name: "LEFTMIDDLE_SYM", text: "@left-middle" },
-    { name: "LEFTBOTTOM_SYM", text: "@left-bottom" },
-    { name: "RIGHTTOP_SYM", text: "@right-top" },
-    { name: "RIGHTMIDDLE_SYM", text: "@right-middle" },
-    { name: "RIGHTBOTTOM_SYM", text: "@right-bottom" },
-
-    /*
-     * The following token names are defined in CSS3 Media Queries: https://www.w3.org/TR/css3-mediaqueries/#syntax
-     */
-    /*{ name: "MEDIA_ONLY", state: "media"},
-    { name: "MEDIA_NOT", state: "media"},
-    { name: "MEDIA_AND", state: "media"},*/
-    { name: "RESOLUTION", state: "media" },
-
-    /*
-     * The following token names are not defined in any CSS specification but are used by the lexer.
-     */
-
-    // not a real token, but useful for stupid IE filters
-    { name: "IE_FUNCTION" },
-
-    // part of CSS3 grammar but not the Flex code
-    { name: "CHAR" },
-
-    // TODO: Needed?
-    // Not defined as tokens, but might as well be
-    {
-        name: "PIPE",
-        text: "|"
-    },
-    {
-        name: "SLASH",
-        text: "/"
-    },
-    {
-        name: "MINUS",
-        text: "-"
-    },
-    {
-        name: "STAR",
-        text: "*"
-    },
-
-    {
-        name: "LBRACE",
-        endChar: "}",
-        text: "{"
-    },
-    {
-        name: "RBRACE",
-        text: "}"
-    },
-    {
-        name: "LBRACKET",
-        endChar: "]",
-        text: "["
-    },
-    {
-        name: "RBRACKET",
-        text: "]"
-    },
-    {
-        name: "EQUALS",
-        text: "="
-    },
-    {
-        name: "COLON",
-        text: ":"
-    },
-    {
-        name: "SEMICOLON",
-        text: ";"
-    },
-    {
-        name: "LPAREN",
-        endChar: ")",
-        text: "("
-    },
-    {
-        name: "RPAREN",
-        text: ")"
-    },
-    {
-        name: "DOT",
-        text: "."
-    }
-];
-
-(function() {
-    var nameMap = [],
-        typeMap = Object.create(null);
-
-    Tokens.UNKNOWN = -1;
-    Tokens.unshift({ name:"EOF" });
-    for (var i=0, len = Tokens.length; i < len; i++) {
-        nameMap.push(Tokens[i].name);
-        Tokens[Tokens[i].name] = i;
-        if (Tokens[i].text) {
-            if (Tokens[i].text instanceof Array) {
-                for (var j=0; j < Tokens[i].text.length; j++) {
-                    typeMap[Tokens[i].text[j]] = i;
-                }
-            } else {
-                typeMap[Tokens[i].text] = i;
-            }
-        }
-    }
-
-    Tokens.name = function(tt) {
-        return nameMap[tt];
-    };
-
-    Tokens.type = function(c) {
-        return typeMap[c] || -1;
-    };
-})();
-
-},{}],19:[function(require,module,exports){
-"use strict";
-
-/* exported Validation */
-
-var Matcher = require("./Matcher");
-var Properties = require("./Properties");
-var ValidationTypes = require("./ValidationTypes");
-var ValidationError = require("./ValidationError");
-var PropertyValueIterator = require("./PropertyValueIterator");
-
-var Validation = module.exports = {
-
-    validate: function(property, value) {
-
-        //normalize name
-        var name        = property.toString().toLowerCase(),
-            expression  = new PropertyValueIterator(value),
-            spec        = Properties[name] || /^-(webkit|moz|ms|o)-(.+)/i.test(name) && Properties[RegExp.$2],
-            part;
-
-        if (!spec) {
-            if (name.indexOf("-") !== 0) {    //vendor prefixed are ok
-                throw new ValidationError("Unknown property '" + property + "'.", property.line, property.col);
-            }
-        } else if (typeof spec !== "number") {
-
-            // All properties accept some CSS-wide values.
-            // https://drafts.csswg.org/css-values-3/#common-keywords
-            if (ValidationTypes.isAny(expression, "inherit | initial | unset")) {
-                if (expression.hasNext()) {
-                    part = expression.next();
-                    throw new ValidationError("Expected end of value but found '" + part + "'.", part.line, part.col);
-                }
-                return;
-            }
-
-            // Property-specific validation.
-            this.singleProperty(spec, expression);
-
-        }
-
-    },
-
-    singleProperty: function(types, expression) {
-
-        var result      = false,
-            value       = expression.value,
-            part;
-
-        result = Matcher.parse(types + ' | <var>').match(expression);
-
-        if (!result) {
-            if (expression.hasNext() && !expression.isFirst()) {
-                part = expression.peek();
-                if (part.name !== 'var' || part.type !== 'function') {
-                    throw new ValidationError("Expected end of value but found '" + part + "'.", part.line, part.col);
-                }
-            } else {
-                throw new ValidationError("Expected (" + ValidationTypes.describe(types) + ") but found '" + value + "'.", value.line, value.col);
-            }
-        } else if (expression.hasNext()) {
-            part = expression.next();
-            if (part.name !== 'var' || part.type !== 'function') {
-                throw new ValidationError("Expected end of value but found '" + part + "'.", part.line, part.col);
-            }
-        }
-
-    }
-
-};
-
-},{"./Matcher":3,"./Properties":7,"./PropertyValueIterator":10,"./ValidationError":20,"./ValidationTypes":21}],20:[function(require,module,exports){
-"use strict";
-
-module.exports = ValidationError;
-
-/**
- * Type to use when a validation error occurs.
- * @class ValidationError
- * @namespace parserlib.util
- * @constructor
- * @param {String} message The error message.
- * @param {int} line The line at which the error occurred.
- * @param {int} col The column at which the error occurred.
- */
-function ValidationError(message, line, col) {
-
-    /**
-     * The column at which the error occurred.
-     * @type int
-     * @property col
-     */
-    this.col = col;
-
-    /**
-     * The line at which the error occurred.
-     * @type int
-     * @property line
-     */
-    this.line = line;
-
-    /**
-     * The text representation of the unit.
-     * @type String
-     * @property text
-     */
-    this.message = message;
-
-}
-
-//inherit from Error
-ValidationError.prototype = new Error();
-
-},{}],21:[function(require,module,exports){
-"use strict";
-
-var ValidationTypes = module.exports;
-
-var Matcher = require("./Matcher");
-
-function copy(to, from) {
-    Object.keys(from).forEach(function(prop) {
-        to[prop] = from[prop];
-    });
-}
-copy(ValidationTypes, {
-
-    isLiteral: function (part, literals) {
-        var text = part.text.toString().toLowerCase(),
-            args = literals.split(" | "),
-            i, len, found = false;
-
-        for (i=0, len=args.length; i < len && !found; i++) {
-            if (args[i].charAt(0) === "<") {
-                found = this.simple[args[i]](part);
-            } else if (args[i].slice(-2) === "()") {
-                found = (part.type === "function" &&
-                         part.name === args[i].slice(0, -2));
-            } else if (text === args[i].toLowerCase()) {
-                found = true;
-            }
-        }
-
-        return found;
-    },
-
-    isSimple: function(type) {
-        return Boolean(this.simple[type]);
-    },
-
-    isComplex: function(type) {
-        return Boolean(this.complex[type]);
-    },
-
-    describe: function(type) {
-        const complex = this.complex[type];
-        const text = complex instanceof Matcher ? complex.toString(0) : type;
-        return this.explode(text);
-    },
-
-    explode(text) {
-        return !text.includes('<') ? text :
-            text.replace(/(<.*?>)([{#?])?/g, (_, rule, mod) => {
-                const ref = this.simple[rule] || this.complex[rule];
-                return !ref || !ref.originalText ? rule :
-                    (mod ? '[' : '') + this.explode(ref.originalText) + (mod ? ']' : '');
-            });
-    },
-    /**
-     * Determines if the next part(s) of the given expression
-     * are any of the given types.
-     */
-    isAny: function (expression, types) {
-        var args = types.split(" | "),
-            i, len, found = false;
-
-        for (i=0, len=args.length; i < len && !found && expression.hasNext(); i++) {
-            found = this.isType(expression, args[i]);
-        }
-
-        return found;
-    },
-
-    /**
-     * Determines if the next part(s) of the given expression
-     * are one of a group.
-     */
-    isAnyOfGroup: function(expression, types) {
-        var args = types.split(" || "),
-            i, len, found = false;
-
-        for (i=0, len=args.length; i < len && !found; i++) {
-            found = this.isType(expression, args[i]);
-        }
-
-        return found ? args[i-1] : false;
-    },
-
-    /**
-     * Determines if the next part(s) of the given expression
-     * are of a given type.
-     */
-    isType: function (expression, type) {
-        var part = expression.peek(),
-            result = false;
-
-        if (type.charAt(0) !== "<") {
-            result = this.isLiteral(part, type);
-            if (result) {
-                expression.next();
-            }
-        } else if (this.simple[type]) {
-            result = this.simple[type](part);
-            if (result) {
-                expression.next();
-            }
-        } else if (this.complex[type] instanceof Matcher) {
-            result = this.complex[type].match(expression);
-        } else {
-            result = this.complex[type](expression);
-        }
-
-        return result;
-    },
-
-
-    simple: {
-        __proto__: null,
-
-        "<absolute-size>":
-            "xx-small | x-small | small | medium | large | x-large | xx-large",
-
-        "<animateable-feature>":
-            "scroll-position | contents | <animateable-feature-name>",
-
-        "<animateable-feature-name>": function(part) {
-            return this["<ident>"](part) &&
-                !/^(unset|initial|inherit|will-change|auto|scroll-position|contents)$/i.test(part);
-        },
-
-        "<angle>": function(part) {
-            return part.type === "angle";
-        },
-
-        "<attachment>": "scroll | fixed | local",
-
-        "<attr>": "attr()",
-
-        // inset() = inset( <shape-arg>{1,4} [round <border-radius>]? )
-        // circle() = circle( [<shape-radius>]? [at <position>]? )
-        // ellipse() = ellipse( [<shape-radius>{2}]? [at <position>]? )
-        // polygon() = polygon( [<fill-rule>,]? [<shape-arg> <shape-arg>]# )
-        "<basic-shape>": "inset() | circle() | ellipse() | polygon()",
-
-        "<bg-image>": "<image> | <gradient> | none",
-
-        "<blend-mode>": "normal | multiply | screen | overlay | darken | lighten | color-dodge | color-burn | hard-light | soft-light | difference | exclusion | hue | saturation | color | luminosity",
-
-        "<border-style>":
-            "none | hidden | dotted | dashed | solid | double | groove | " +
-            "ridge | inset | outset",
-
-        "<border-width>": "<length> | thin | medium | thick",
-
-        "<box>": "padding-box | border-box | content-box",
-
-        "<clip-source>": "<uri>",
-
-        "<color>": function(part) {
-            return part.type === "color" || String(part) === "transparent" || String(part) === "currentColor";
-        },
-
-        // The SVG <color> spec doesn't include "currentColor" or "transparent" as a color.
-        "<color-svg>": function(part) {
-            return part.type === "color";
-        },
-
-        "<content>": "content()",
-
-        "<content-distribution>": "space-between | space-around | space-evenly | stretch",
-        "<content-position>": "center | start | end | flex-start | flex-end",
-
-        // https://www.w3.org/TR/css3-sizing/#width-height-keywords
-        "<content-sizing>":
-            "fill-available | -moz-available | -webkit-fill-available | " +
-            "max-content | -moz-max-content | -webkit-max-content | " +
-            "min-content | -moz-min-content | -webkit-min-content | " +
-            "fit-content | -moz-fit-content | -webkit-fit-content",
-
-        "<cubic-bezier>": function(part) {
-            return part.type === 'function' &&
-                /^cubic-bezier$/i.test(part.name) &&
-                part.expr && part.expr.parts.length === 7 &&
-                part.expr.parts.every((p, i) => i % 2 ? p.text === ',' : this['<number>'](p));
-        },
-
-        "<cubic-bezier-timing-function>":
-            "ease | ease-in | ease-out | ease-in-out | <cubic-bezier>",
-
-        "<feature-tag-value>": function(part) {
-            return part.type === "function" && /^[A-Z0-9]{4}$/i.test(part);
-        },
-
-        // custom() isn't actually in the spec
-        "<filter-function>":
-            "blur() | brightness() | contrast() | custom() | " +
-            "drop-shadow() | grayscale() | hue-rotate() | invert() | " +
-            "opacity() | saturate() | sepia()",
-
-        "<flex>": function(part) {
-            return part.type === "function" || part.type === "grid" && part.value >= 0;
-        },
-
-        "<flex-basis>": "<width>",
-
-        "<flex-direction>": "row | row-reverse | column | column-reverse",
-
-        "<flex-grow>": "<number>",
-
-        "<flex-shrink>": "<number>",
-
-        "<flex-wrap>": "nowrap | wrap | wrap-reverse",
-
-        "<font-size>":
-            "<absolute-size> | <relative-size> | <length> | <percentage>",
-
-        "<font-stretch>":
-            "normal | ultra-condensed | extra-condensed | condensed | " +
-            "semi-condensed | semi-expanded | expanded | extra-expanded | " +
-            "ultra-expanded",
-
-        "<font-style>": "normal | italic | oblique",
-
-        "<font-variant-caps>":
-            "small-caps | all-small-caps | petite-caps | all-petite-caps | " +
-            "unicase | titling-caps",
-
-        "<font-variant-css21>": "normal | small-caps",
-
-        "<font-weight>":
-            "normal | bold | bolder | lighter | " +
-            "100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900",
-
-        "<frames-timing-function>": function({type, name, expr}) {
-            return type === 'function' &&
-                /^frames$/i.test(name) &&
-                expr.parts.length === 1 &&
-                this['<integer>'](expr.parts[0]);
-        },
-
-        "<generic-family>":
-            "serif | sans-serif | cursive | fantasy | monospace",
-
-        "<geometry-box>": "<shape-box> | fill-box | stroke-box | view-box",
-
-        "<glyph-angle>": function(part) {
-            return part.type === "angle" && part.units === "deg";
-        },
-
-        "<gradient>": function(part) {
-            return part.type === "function" && /^(?:\-(?:ms|moz|o|webkit)\-)?(?:repeating\-)?(?:radial\-|linear\-)?gradient/i.test(part);
-        },
-
-        "<icccolor>":
-            "cielab() | cielch() | cielchab() | " +
-            "icc-color() | icc-named-color()",
-
-        //any identifier
-        "<ident>": function(part) {
-            return part.type === "identifier" || part.wasIdent;
-        },
-
-        "<ident-not-span>": function(part) {
-            return (part.type === "identifier" || part.wasIdent) && !/^span$/i.test(part.value);
-        },
-
-        "<ident-not-generic-family>": function(part) {
-            return this["<ident>"](part) && !this["<generic-family>"](part);
-        },
-
-        "<image>": "<uri>",
-
-        "<integer>": function(part) {
-            return part.type === "integer";
-        },
-
-        "<length>": function(part) {
-            if (part.type === "function" && /^(?:\-(?:ms|moz|o|webkit)\-)?calc/i.test(part)) {
-                return true;
-            } else {
-                return part.type === "length" || part.type === "number" || part.type === "integer" || String(part) === "0";
-            }
-        },
-
-        "<length-percentage>": "<length> | <percentage>",
-
-        "<line>": function(part) {
-            return part.type === "integer";
-        },
-
-        "<line-height>": "<number> | <length> | <percentage> | normal",
-
-        "<margin-width>": "<length> | <percentage> | auto",
-
-        "<miterlimit>": function(part) {
-            return this["<number>"](part) && part.value >= 1;
-        },
-
-        "<nonnegative-length-or-percentage>": function(part) {
-            return (this["<length>"](part) || this["<percentage>"](part)) &&
-                (String(part) === "0" || part.type === "function" || (part.value) >= 0);
-        },
-
-        "<nonnegative-number-or-percentage>": function(part) {
-            return (this["<number>"](part) || this["<percentage>"](part)) &&
-                (String(part) === "0" || part.type === "function" || (part.value) >= 0);
-        },
-
-        "<positive-integer>": function(part) {
-            return this["<number>"](part) && (part.type === "function" || part.value > 0);
-        },
-
-        "<number>": function(part) {
-            return part.type === "number" || this["<integer>"](part);
-        },
-
-        "<opacity-value>": function(part) {
-            return this["<number>"](part) && part.value >= 0 && part.value <= 1;
-        },
-
-        "<overflow-position>": "unsafe | safe",
-
-        "<padding-width>": "<nonnegative-length-or-percentage>",
-
-        "<percentage>": function(part) {
-            return part.type === "percentage" || String(part) === "0";
-        },
-
-        "<relative-size>": "smaller | larger",
-
-        "<self-position>": "center | start | end | self-start | self-end | flex-start | flex-end",
-
-        "<shape>": "rect() | inset-rect()",
-
-        "<shape-box>": "<box> | margin-box",
-
-        "<single-animation-direction>":
-            "normal | reverse | alternate | alternate-reverse",
-
-        "<single-animation-fill-mode>":
-            "none | forwards | backwards | both",
-
-        "<single-animation-name>": function(part) {
-            return this["<ident>"](part) &&
-                /^-?[a-z_][-a-z0-9_]+$/i.test(part) &&
-                !/^(none|unset|initial|inherit)$/i.test(part);
-        },
-
-        "<step-timing-function>": "step-start | step-end | <steps>",
-
-        "<steps>": function({type, name, expr}) {
-            return type === 'function' &&
-                /^steps$/i.test(name) &&
-                expr.parts.length &&
-                this['<integer>'](expr.parts[0]) && (expr.parts.length === 1 ||
-                    expr.parts.length === 3 &&
-                    expr.parts[1].text === ',' &&
-                    /^(start|end)$/i.test(expr.parts[2])
-                );
-        },
-
-        "<string>": function(part) {
-            return part.type === "string";
-        },
-
-        "<time>": function(part) {
-            return part.type === "time";
-        },
-
-        "<transform-function>": function(part) {
-            const name = part.name.toLowerCase();
-            const parts = part.expr && part.expr.parts;
-            const len = parts && parts.length;
-            if (!len) return false;
-            const p0 = parts[0];
-            return (
-                name === 'matrix' ? len % 2 && len <= 11 &&
-                    parts.every((p, i) => i % 2 ? p.text === ',' : this['<number>'](p)) :
-                name === 'translate' ? len % 2 && len <= 3 &&
-                    parts.every((p, i) => i % 2 ? p.text === ',' : this['<length-percentage>'](p)) :
-                name === 'translatex' ? len === 1 && this['<length-percentage>'](p0) :
-                name === 'translatey' ? len === 1 && this['<length-percentage>'](p0) :
-                name === 'scale' ? len % 2 && len <= 3 &&
-                    parts.every((p, i) => i % 2 ? p.text === ',' : this['<number>'](p)) :
-                name === 'scalex' ? len === 1 && this['<number>'](p0) :
-                name === 'scaley' ? len === 1 && this['<number>'](p0) :
-                name === 'rotate' ? len === 1 && p0.text === '0' || this['<angle>'](p0) :
-                name === 'skew' ? len % 2 && len <= 3 &&
-                    parts.every((p, i) => i % 2 ? p.text === ',' : p.text === '0' || this['<angle>'](p)) :
-                name === 'skewx' ? len === 1 && p0.text === '0' || this['<angle>'](p0) :
-                name === 'skewy' ? len === 1 && p0.text === '0' || this['<angle>'](p0) :
-                false
-            );
-        },
-
-        "<unicode-range>": function(part) {
-            return /^U\+[0-9a-f?]{1,6}(-[0-9a-f?]{1,6})?\s*$/i.test(part);
-        },
-
-        "<uri>": function(part) {
-            return part.type === "uri";
-        },
-
-        "<var>": "var()",
-
-        "<width>": "<margin-width>"
-    },
-
-    complex: {
-        __proto__: null,
-
-        "<align-content>":
-            "normal | <baseline-position> | <content-distribution> | <overflow-position>? <content-position>",
-
-        "<align-self>":
-            "auto | normal | stretch | <baseline-position> | <overflow-position>? <self-position>",
-
-        "<azimuth>":
-            "<angle>" +
-            " | " +
-            "[ [ left-side | far-left | left | center-left | center | " +
-            "center-right | right | far-right | right-side ] || behind ]" +
-            " | "+
-            "leftwards | rightwards",
-
-        "<baseline-position>": "[ first | last ]? baseline",
-
-        "<bg-layer>": "<bg-image> || <bg-position> [ / <bg-size> ]? || <repeat-style> || <attachment> || <box> || <box>",
-
-        "<bg-position>":
-            "[ center | [ left | right ] <length-percentage>? ] && [ center | [ top | bottom ] <length-percentage>? ] | " +
-            "[ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ] | " +
-            "[ left | center | right | top | bottom | <length-percentage> ]",
-
-        "<bg-size>":
-            "[ <length> | <percentage> | auto ]{1,2} | cover | contain",
-
-        "<border-image-outset>": "[ <length> | <number> ]{1,4}",
-        "<border-image-repeat>": "[ stretch | repeat | round | space ]{1,2}",
-        "<border-image-slice>":
-        // [<number> | <percentage>]{1,4} && fill?
-        // *but* fill can appear between any of the numbers
-        Matcher.many([true /* first element is required */],
-                     Matcher.cast("<nonnegative-number-or-percentage>"),
-                     Matcher.cast("<nonnegative-number-or-percentage>"),
-                     Matcher.cast("<nonnegative-number-or-percentage>"),
-                     Matcher.cast("<nonnegative-number-or-percentage>"),
-                     "fill"),
-        "<border-image-width>": "[ <length> | <percentage> | <number> | auto ]{1,4}",
-        "<border-radius>":
-            "<nonnegative-length-or-percentage>{1,4} " +
-            "[ / <nonnegative-length-or-percentage>{1,4} ]?",
-
-        "<box-shadow>": "none | <shadow>#",
-
-        "<clip-path>": "<basic-shape> || <geometry-box>",
-
-        "<dasharray>":
-        // "list of comma and/or white space separated <length>s and
-        // <percentage>s".  There is a non-negative constraint.
-        Matcher.cast("<nonnegative-length-or-percentage>")
-            .braces(1, Infinity, "#", Matcher.cast(",").question()),
-
-        "<family-name>":
-            // <string> | <IDENT>+
-            "<string> | <ident-not-generic-family> <ident>*",
-
-        "<filter-function-list>": "[ <filter-function> | <uri> ]+",
-
-        // https://www.w3.org/TR/2014/WD-css-flexbox-1-20140325/#flex-property
-        "<flex-shorthand>":
-            "none | [ <flex-grow> <flex-shrink>? || <flex-basis> ]",
-
-        "<font-family>": "[ <generic-family> | <family-name> ]#",
-
-        "<font-shorthand>":
-            "[ <font-style> || <font-variant-css21> || " +
-            "<font-weight> || <font-stretch> ]? <font-size> " +
-            "[ / <line-height> ]? <font-family>",
-
-        "<font-variant-alternates>":
-            // stylistic(<feature-value-name>)
-            "stylistic() || " +
-            "historical-forms || " +
-            // styleset(<feature-value-name> #)
-            "styleset() || " +
-            // character-variant(<feature-value-name> #)
-            "character-variant() || " +
-            // swash(<feature-value-name>)
-            "swash() || " +
-            // ornaments(<feature-value-name>)
-            "ornaments() || " +
-            // annotation(<feature-value-name>)
-            "annotation()",
-
-        "<font-variant-ligatures>":
-            // <common-lig-values>
-            "[ common-ligatures | no-common-ligatures ] || " +
-            // <discretionary-lig-values>
-            "[ discretionary-ligatures | no-discretionary-ligatures ] || " +
-            // <historical-lig-values>
-            "[ historical-ligatures | no-historical-ligatures ] || " +
-            // <contextual-alt-values>
-            "[ contextual | no-contextual ]",
-
-        "<font-variant-numeric>":
-            // <numeric-figure-values>
-            "[ lining-nums | oldstyle-nums ] || " +
-            // <numeric-spacing-values>
-            "[ proportional-nums | tabular-nums ] || " +
-            // <numeric-fraction-values>
-            "[ diagonal-fractions | stacked-fractions ] || " +
-            "ordinal || slashed-zero",
-
-        "<font-variant-east-asian>":
-            // <east-asian-variant-values>
-            "[ jis78 | jis83 | jis90 | jis04 | simplified | traditional ] || " +
-            // <east-asian-width-values>
-            "[ full-width | proportional-width ] || " +
-            "ruby",
-
-        "<grid-auto-columns>":        "<track-size>+",
-        "<grid-auto-rows>":           "<track-size>+",
-        "<grid-template>":            "none | [ <grid-template-rows> / <grid-template-columns> ] | [ <line-names>? <string> <track-size>? <line-names>? ]+ [ / <explicit-track-list> ]?",
-        "<grid-template-columns>":    "none | <track-list> | <auto-track-list>",
-        "<grid-template-rows>":       "<grid-template-columns>",
-        "<grid-line>":                "auto | <ident-not-span> | [ <integer> && <ident-not-span>? ] | [ span && [ <integer> || <ident-not-span> ] ]",
-        "<auto-repeat>":              "repeat( [ auto-fill | auto-fit ] , [ <line-names>? <fixed-size> ]+ <line-names>? )",
-        "<auto-track-list>":          "[ <line-names>? [ <fixed-size> | <fixed-repeat> ] ]* <line-names>? <auto-repeat> [ <line-names>? [ <fixed-size> | <fixed-repeat> ] ]* <line-names>?",
-        "<explicit-track-list>":      "[ <line-names>? <track-size> ]+ <line-names>?",
-        "<fixed-breadth>":            "<length-percentage>",
-        "<fixed-repeat>":             "repeat( [ <positive-integer> ] , [ <line-names>? <fixed-size> ]+ <line-names>? )",
-        "<fixed-size>":               "<fixed-breadth> | minmax( <fixed-breadth> , <track-breadth> ) | minmax( <inflexible-breadth> , <fixed-breadth> )",
-        "<inflexible-breadth>":       "<length-percentage> | min-content | max-content | auto",
-        "<line-names>":               "[ <ident-not-span>* ]",
-        "<track-breadth>":            "<length-percentage> | <flex> | min-content | max-content | auto",
-        "<track-list>":               "[ <line-names>? [ <track-size> | <track-repeat> ] ]+ <line-names>?",
-        "<track-repeat>":             "repeat( [ <positive-integer> ] , [ <line-names>? <track-size> ]+ <line-names>? )",
-        "<track-size>":               "<track-breadth> | minmax( <inflexible-breadth> , <track-breadth> ) | fit-content( <length-percentage> )",
-        "<column-gap>":               "normal | <length> | <percentage>",
-        "<row-gap>":                  "<column-gap>",
-
-        "<justify-content>":
-            "normal | <content-distribution> | <overflow-position>? [ <content-position> | left | right ]",
-
-        "<justify-self>":
-            "auto | normal | stretch | <baseline-position> | <overflow-position>? [ <self-position> | left | right ]",
-
-        // Note that <color> here is "as defined in the SVG spec", which
-        // is more restrictive that the <color> defined in the CSS spec.
-        // none | currentColor | <color> [<icccolor>]? |
-        // <funciri> [ none | currentColor | <color> [<icccolor>]? ]?
-        "<paint>": "<paint-basic> | <uri> <paint-basic>?",
-
-        // Helper definition for <paint> above.
-        // Note: "transparent" is an accepted color now in SVG
-        "<paint-basic>": "none | currentColor | <color-svg> <icccolor>? | transparent",
-
-        "<position>":
-            // Because our `alt` combinator is ordered, we need to test these
-            // in order from longest possible match to shortest.
-            "[ [ left | right ] <length-percentage> ] && [ [ top | bottom ] <length-percentage> ] | " +
-            "[ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ]? | " +
-            "[ left | center | right ] || [ top | center | bottom ]",
-
-        "<repeat-style>":
-            "repeat-x | repeat-y | [ repeat | space | round | no-repeat ]{1,2}",
-
-        "<shadow>":
-        //inset? && [ <length>{2,4} && <color>? ]
-        Matcher.many([true /* length is required */],
-                     Matcher.cast("<length>").braces(2, 4), "inset", "<color>"),
-
-        "<single-timing-function>":
-            "linear | <cubic-bezier-timing-function> | <step-timing-function> | <frames-timing-function>",
-
-        "<text-decoration-color>":
-           "<color>",
-
-        "<text-decoration-line>":
-            "none | [ underline || overline || line-through || blink ]",
-
-        "<text-decoration-style>":
-            "solid | double | dotted | dashed | wavy",
-
-        "<transform-origin>":
-            "[ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ] <length>? | " +
-            "[ left | center | right | top | bottom | <length-percentage> ] | " +
-            "[ [ center | left | right ] && [ center | top | bottom ] ] <length>?",
-
-        "<transition>":
-            "[ none | [ all | <ident> ]# ] || <time> || <single-timing-function> || <time>",
-
-        "<will-change>":
-            "auto | <animateable-feature>#",
-
-        "<x-one-radius>":
-            //[ <length> | <percentage> ] [ <length> | <percentage> ]?
-            "[ <length> | <percentage> ]{1,2}"
-    }
-});
-
-Object.keys(ValidationTypes.simple).forEach(function(nt) {
-    var rule = ValidationTypes.simple[nt];
-    if (typeof rule === "string") {
-        ValidationTypes.simple[nt] = Object.defineProperty(function(part) {
-            return ValidationTypes.isLiteral(part, rule);
-        }, 'originalText', {value: rule});
-    }
-});
-
-Object.keys(ValidationTypes.complex).forEach(function(nt) {
-    var rule = ValidationTypes.complex[nt];
-    if (typeof rule === "string") {
-        ValidationTypes.complex[nt] = Object.defineProperty(Matcher.parse(rule), 'originalText', {value: rule});
-    }
-});
-
-// Because this is defined relative to other complex validation types,
-// we need to define it *after* the rest of the types are initialized.
-ValidationTypes.complex["<font-variant>"] =
-    Matcher.oror({ expand: "<font-variant-ligatures>" },
-                 { expand: "<font-variant-alternates>" },
-                 "<font-variant-caps>",
-                 { expand: "<font-variant-numeric>" },
-                 { expand: "<font-variant-east-asian>" });
-
-},{"./Matcher":3}],22:[function(require,module,exports){
-"use strict";
-
-module.exports = {
-    Colors            : require("./Colors"),
-    Combinator        : require("./Combinator"),
-    Parser            : require("./Parser"),
-    PropertyName      : require("./PropertyName"),
-    PropertyValue     : require("./PropertyValue"),
-    PropertyValuePart : require("./PropertyValuePart"),
-    Matcher           : require("./Matcher"),
-    MediaFeature      : require("./MediaFeature"),
-    MediaQuery        : require("./MediaQuery"),
-    Selector          : require("./Selector"),
-    SelectorPart      : require("./SelectorPart"),
-    SelectorSubPart   : require("./SelectorSubPart"),
-    Specificity       : require("./Specificity"),
-    TokenStream       : require("./TokenStream"),
-    Tokens            : require("./Tokens"),
-    ValidationError   : require("./ValidationError")
-};
-
-},{"./Colors":1,"./Combinator":2,"./Matcher":3,"./MediaFeature":4,"./MediaQuery":5,"./Parser":6,"./PropertyName":8,"./PropertyValue":9,"./PropertyValuePart":11,"./Selector":13,"./SelectorPart":14,"./SelectorSubPart":15,"./Specificity":16,"./TokenStream":17,"./Tokens":18,"./ValidationError":20}],23:[function(require,module,exports){
-"use strict";
-
-module.exports = EventTarget;
-
-/**
- * A generic base to inherit from for any object
- * that needs event handling.
- * @class EventTarget
- * @constructor
- */
-function EventTarget() {
-
-    /**
-     * The array of listeners for various events.
-     * @type Object
-     * @property _listeners
-     * @private
-     */
-    this._listeners = Object.create(null);
-}
-
-EventTarget.prototype = {
-
-    //restore constructor
-    constructor: EventTarget,
-
-    /**
-     * Adds a listener for a given event type.
-     * @param {String} type The type of event to add a listener for.
-     * @param {Function} listener The function to call when the event occurs.
-     * @return {void}
-     * @method addListener
-     */
-    addListener: function(type, listener) {
-        if (!this._listeners[type]) {
-            this._listeners[type] = [];
-        }
-
-        this._listeners[type].push(listener);
-    },
-
-    /**
-     * Fires an event based on the passed-in object.
-     * @param {Object|String} event An object with at least a 'type' attribute
-     *      or a string indicating the event name.
-     * @return {void}
-     * @method fire
-     */
-    fire: function(event) {
-        if (typeof event === "string") {
-            event = { type: event };
-        }
-        if (typeof event.target !== "undefined") {
-            event.target = this;
-        }
-
-        if (typeof event.type === "undefined") {
-            throw new Error("Event object missing 'type' property.");
-        }
-
-        var listeners = this._listeners[event.type];
-        if (listeners) {
-            //create a copy of the array and use that so listeners can't chane
-            listeners = listeners.slice();
-            for (var i=0, len=listeners.length; i < len; i++) {
-                listeners[i].call(this, event);
-            }
-        }
-    },
-
-    /**
-     * Removes a listener for a given event type.
-     * @param {String} type The type of event to remove a listener from.
-     * @param {Function} listener The function to remove from the event.
-     * @return {void}
-     * @method removeListener
-     */
-    removeListener: function(type, listener) {
-        if (this._listeners[type]) {
-            var listeners = this._listeners[type];
-            for (var i=0, len=listeners.length; i < len; i++) {
-                if (listeners[i] === listener) {
-                    listeners.splice(i, 1);
-                    break;
-                }
-            }
-
-
-        }
-    }
-};
-
-},{}],24:[function(require,module,exports){
-"use strict";
-
-module.exports = StringReader;
-
-/**
- * Convenient way to read through strings.
- * @namespace parserlib.util
- * @class StringReader
- * @constructor
- * @param {String} text The text to read.
- */
-function StringReader(text) {
-
-    /**
-     * The input text with line endings normalized.
-     * @property _input
-     * @type String
-     * @private
-     */
-    this._input = text.replace(/(\r\n?|\n)/g, "\n");
-
-
-    /**
-     * The row for the character to be read next.
-     * @property _line
-     * @type int
-     * @private
-     */
-    this._line = 1;
-
-
-    /**
-     * The column for the character to be read next.
-     * @property _col
-     * @type int
-     * @private
-     */
-    this._col = 1;
-
-    /**
-     * The index of the character in the input to be read next.
-     * @property _cursor
-     * @type int
-     * @private
-     */
-    this._cursor = 0;
-}
-
-StringReader.prototype = {
-
-    // restore constructor
-    constructor: StringReader,
-
-    //-------------------------------------------------------------------------
-    // Position info
-    //-------------------------------------------------------------------------
-
-    /**
-     * Returns the column of the character to be read next.
-     * @return {int} The column of the character to be read next.
-     * @method getCol
-     */
-    getCol: function() {
-        return this._col;
-    },
-
-    /**
-     * Returns the row of the character to be read next.
-     * @return {int} The row of the character to be read next.
-     * @method getLine
-     */
-    getLine: function() {
-        return this._line;
-    },
-
-    /**
-     * Determines if you're at the end of the input.
-     * @return {Boolean} True if there's no more input, false otherwise.
-     * @method eof
-     */
-    eof: function() {
-        return this._cursor === this._input.length;
-    },
-
-    //-------------------------------------------------------------------------
-    // Basic reading
-    //-------------------------------------------------------------------------
-
-    /**
-     * Reads the next character without advancing the cursor.
-     * @param {int} count How many characters to look ahead (default is 1).
-     * @return {String} The next character or null if there is no next character.
-     * @method peek
-     */
-    peek: function(count) {
-        var c = null;
-        count = typeof count === "undefined" ? 1 : count;
-
-        // if we're not at the end of the input...
-        if (this._cursor < this._input.length) {
-
-            // get character and increment cursor and column
-            c = this._input.charAt(this._cursor + count - 1);
-        }
-
-        return c;
-    },
-
-    /**
-     * Reads the next character from the input and adjusts the row and column
-     * accordingly.
-     * @return {String} The next character or null if there is no next character.
-     * @method read
-     */
-    read: function() {
-        var c = null;
-
-        // if we're not at the end of the input...
-        if (this._cursor < this._input.length) {
-
-            // if the last character was a newline, increment row count
-            // and reset column count
-            if (this._input.charAt(this._cursor) === "\n") {
-                this._line++;
-                this._col=1;
-            } else {
-                this._col++;
-            }
-
-            // get character and increment cursor and column
-            c = this._input.charAt(this._cursor++);
-        }
-
-        return c;
-    },
-
-    //-------------------------------------------------------------------------
-    // Misc
-    //-------------------------------------------------------------------------
-
-    /**
-     * Saves the current location so it can be returned to later.
-     * @method mark
-     * @return {void}
-     */
-    mark: function() {
-        this._bookmark = {
-            cursor: this._cursor,
-            line:   this._line,
-            col:    this._col
-        };
-    },
-
-    reset: function() {
-        if (this._bookmark) {
-            this._cursor = this._bookmark.cursor;
-            this._line = this._bookmark.line;
-            this._col = this._bookmark.col;
-            delete this._bookmark;
-        }
-    },
-
-    //-------------------------------------------------------------------------
-    // Advanced reading
-    //-------------------------------------------------------------------------
-
-    /**
-     * Reads up to and including the given string. Throws an error if that
-     * string is not found.
-     * @param {String} pattern The string to read.
-     * @return {String} The string when it is found.
-     * @throws Error when the string pattern is not found.
-     * @method readTo
-     */
-    readTo: function(pattern) {
-
-        var buffer = "",
-            c;
-
-        /*
-         * First, buffer must be the same length as the pattern.
-         * Then, buffer must end with the pattern or else reach the
-         * end of the input.
-         */
-        while (buffer.length < pattern.length || buffer.lastIndexOf(pattern) !== buffer.length - pattern.length) {
-            c = this.read();
-            if (c) {
-                buffer += c;
-            } else {
-                throw new Error("Expected \"" + pattern + "\" at line " + this._line  + ", col " + this._col + ".");
-            }
-        }
-
-        return buffer;
-
-    },
-
-    /**
-     * Reads characters while each character causes the given
-     * filter function to return true. The function is passed
-     * in each character and either returns true to continue
-     * reading or false to stop.
-     * @param {Function} filter The function to read on each character.
-     * @return {String} The string made up of all characters that passed the
-     *      filter check.
-     * @method readWhile
-     */
-    readWhile: function(filter) {
-
-        var buffer = [],
-            c = this.peek();
-
-        while (c !== null && filter(c)) {
-            buffer.push(this.read());
-            c = this.peek();
-        }
-
-        return buffer.join('');
-
-    },
-
-    /**
-     * Reads characters that match either text or a regular expression and
-     * returns those characters. If a match is found, the row and column
-     * are adjusted; if no match is found, the reader's state is unchanged.
-     * reading or false to stop.
-     * @param {String|RegExp} matcher If a string, then the literal string
-     *      value is searched for. If a regular expression, then any string
-     *      matching the pattern is search for.
-     * @return {String} The string made up of all characters that matched or
-     *      null if there was no match.
-     * @method readMatch
-     */
-    readMatch: function(matcher) {
-
-        if (matcher.sticky) {
-            matcher.lastIndex = this._cursor;
-            if (matcher.test(this._input)) {
-                return this.readCount(RegExp.lastMatch.length);
-            }
-            return null;
-        }
-
-        if (typeof matcher === "string") {
-            if (this._input.substr(this._cursor, matcher.length) === matcher) {
-                return this.readCount(matcher.length);
-            }
-        } else if (matcher instanceof RegExp) {
-            if (matcher.test(this._input.substr(this._cursor))) {
-                return this.readCount(RegExp.lastMatch.length);
-            }
-        }
-
-        return null;
-    },
-
-
-    /**
-     * Reads a given number of characters. If the end of the input is reached,
-     * it reads only the remaining characters and does not throw an error.
-     * @param {int} count The number of characters to read.
-     * @return {String} The string made up the read characters.
-     * @method readCount
-     */
-    readCount: function(count) {
-        const len = this._input.length;
-        if (this._cursor >= len) return null;
-        const text = this._input.substr(this._cursor, count);
-        this._cursor = Math.min(this._cursor + count, len);
-        let prev = -1;
-        for (let i = 0; (i = text.indexOf('\n', i)) >= 0; prev = i, i++) {
-            this._line++;
-        }
-        this._col = prev < 0 ? this._col + count : count - prev;
-        return text;
-    }
-
-};
-
-},{}],25:[function(require,module,exports){
-"use strict";
-
-module.exports = SyntaxError;
-
-/**
- * Type to use when a syntax error occurs.
- * @class SyntaxError
- * @namespace parserlib.util
- * @constructor
- * @param {String} message The error message.
- * @param {int} line The line at which the error occurred.
- * @param {int} col The column at which the error occurred.
- */
-function SyntaxError(message, line, col) {
-    Error.call(this);
-    this.name = this.constructor.name;
-
-    /**
-     * The column at which the error occurred.
-     * @type int
-     * @property col
-     */
-    this.col = col;
-
-    /**
-     * The line at which the error occurred.
-     * @type int
-     * @property line
-     */
-    this.line = line;
-
-    /**
-     * The text representation of the unit.
-     * @type String
-     * @property text
-     */
-    this.message = message;
-
-}
-
-//inherit from Error
-SyntaxError.prototype = Object.create(Error.prototype); // jshint ignore:line
-SyntaxError.prototype.constructor = SyntaxError; // jshint ignore:line
-
-},{}],26:[function(require,module,exports){
-"use strict";
-
-module.exports = SyntaxUnit;
-
-/**
- * Base type to represent a single syntactic unit.
- * @class SyntaxUnit
- * @namespace parserlib.util
- * @constructor
- * @param {String} text The text of the unit.
- * @param {int} line The line of text on which the unit resides.
- * @param {int} col The column of text on which the unit resides.
- */
-function SyntaxUnit(text, line, col, type) {
-
-
-    /**
-     * The column of text on which the unit resides.
-     * @type int
-     * @property col
-     */
-    this.col = col;
-
-    /**
-     * The line of text on which the unit resides.
-     * @type int
-     * @property line
-     */
-    this.line = line;
-
-    /**
-     * The text representation of the unit.
-     * @type String
-     * @property text
-     */
-    this.text = text;
-
-    /**
-     * The type of syntax unit.
-     * @type int
-     * @property type
-     */
-    this.type = type;
-}
-
-/**
- * Create a new syntax unit based solely on the given token.
- * Convenience method for creating a new syntax unit when
- * it represents a single token instead of multiple.
- * @param {Object} token The token object to represent.
- * @return {parserlib.util.SyntaxUnit} The object representing the token.
- * @static
- * @method fromToken
- */
-SyntaxUnit.fromToken = function(token) {
-    return new SyntaxUnit(token.value, token.startLine, token.startCol);
-};
-
-SyntaxUnit.prototype = {
-
-    //restore constructor
-    constructor: SyntaxUnit,
-
-    /**
-     * Returns the text representation of the unit.
-     * @return {String} The text representation of the unit.
-     * @method valueOf
-     */
-    valueOf: function() {
-        return this.toString();
-    },
-
-    /**
-     * Returns the text representation of the unit.
-     * @return {String} The text representation of the unit.
-     * @method toString
-     */
-    toString: function() {
-        return this.text;
-    }
-
-};
-
-},{}],27:[function(require,module,exports){
-"use strict";
-
-module.exports = TokenStreamBase;
-
-var StringReader = require("./StringReader");
-var SyntaxError = require("./SyntaxError");
-
-/**
- * Generic TokenStream providing base functionality.
- * @class TokenStreamBase
- * @namespace parserlib.util
- * @constructor
- * @param {String|StringReader} input The text to tokenize or a reader from
- *      which to read the input.
- */
-function TokenStreamBase(input, tokenData) {
-
-    /**
-     * The string reader for easy access to the text.
-     * @type StringReader
-     * @property _reader
-     * @private
-     */
-    this._reader = new StringReader(input ? input.toString() : "");
-
-    /**
-     * Token object for the last consumed token.
-     * @type Token
-     * @property _token
-     * @private
-     */
-    this._token = null;
-
-    /**
-     * The array of token information.
-     * @type Array
-     * @property _tokenData
-     * @private
-     */
-    this._tokenData = tokenData;
-
-    /**
-     * Lookahead token buffer.
-     * @type Array
-     * @property _lt
-     * @private
-     */
-    this._lt = [];
-
-    /**
-     * Lookahead token buffer index.
-     * @type int
-     * @property _ltIndex
-     * @private
-     */
-    this._ltIndex = 0;
-
-    this._ltIndexCache = [];
-}
-
-/**
- * Accepts an array of token information and outputs
- * an array of token data containing key-value mappings
- * and matching functions that the TokenStream needs.
- * @param {Array} tokens An array of token descriptors.
- * @return {Array} An array of processed token data.
- * @method createTokenData
- * @static
- */
-TokenStreamBase.createTokenData = function(tokens) {
-
-    var nameMap     = [],
-        typeMap     = Object.create(null),
-        tokenData     = tokens.concat([]),
-        i            = 0,
-        len            = tokenData.length+1;
-
-    tokenData.UNKNOWN = -1;
-    tokenData.unshift({ name:"EOF" });
-
-    for (; i < len; i++) {
-        nameMap.push(tokenData[i].name);
-        tokenData[tokenData[i].name] = i;
-        if (tokenData[i].text) {
-            typeMap[tokenData[i].text] = i;
-        }
-    }
-
-    tokenData.name = function(tt) {
-        return nameMap[tt];
-    };
-
-    tokenData.type = function(c) {
-        return typeMap[c];
-    };
-
-    return tokenData;
-};
-
-TokenStreamBase.prototype = {
-
-    //restore constructor
-    constructor: TokenStreamBase,
-
-    //-------------------------------------------------------------------------
-    // Matching methods
-    //-------------------------------------------------------------------------
-
-    /**
-     * Determines if the next token matches the given token type.
-     * If so, that token is consumed; if not, the token is placed
-     * back onto the token stream. You can pass in any number of
-     * token types and this will return true if any of the token
-     * types is found.
-     * @param {int|int[]} tokenTypes Either a single token type or an array of
-     *      token types that the next token might be. If an array is passed,
-     *      it's assumed that the token can be any of these.
-     * @param {variant} channel (Optional) The channel to read from. If not
-     *      provided, reads from the default (unnamed) channel.
-     * @return {Boolean} True if the token type matches, false if not.
-     * @method match
-     */
-    match: function(tokenTypes, channel) {
-        var isArray = Array.isArray(tokenTypes);
-        do {
-            var tt = this.get(channel);
-            if (isArray ? tokenTypes.includes(tt) : tt === tokenTypes) {
-                return true;
-            }
-        } while (tt === this._tokenData.COMMENT && this.LA(0) !== 0);
-
-        //no match found, put the token back
-        this.unget();
-        return false;
-    },
-
-    /**
-     * Determines if the next token matches the given token type.
-     * If so, that token is consumed; if not, an error is thrown.
-     * @param {int|int[]} tokenTypes Either a single token type or an array of
-     *      token types that the next token should be. If an array is passed,
-     *      it's assumed that the token must be one of these.
-     * @return {void}
-     * @method mustMatch
-     */
-    mustMatch: function(tokenTypes) {
-        if (!this.match(tokenTypes)) {
-            var token = this.LT(1);
-            const info = this._tokenData[Array.isArray(tokenTypes) ? tokenTypes[0] : tokenTypes];
-            throw new SyntaxError("Expected " + (info.text || info.name) +
-                " at line " + token.startLine + ", col " + token.startCol + ".", token.startLine, token.startCol);
-        }
-    },
-
-    //-------------------------------------------------------------------------
-    // Consuming methods
-    //-------------------------------------------------------------------------
-
-    /**
-     * Keeps reading from the token stream until either one of the specified
-     * token types is found or until the end of the input is reached.
-     * @param {int|int[]} tokenTypes Either a single token type or an array of
-     *      token types that the next token should be. If an array is passed,
-     *      it's assumed that the token must be one of these.
-     * @param {variant} channel (Optional) The channel to read from. If not
-     *      provided, reads from the default (unnamed) channel.
-     * @return {void}
-     * @method advance
-     */
-    advance: function(tokenTypes, channel) {
-
-        while (this.LA(0) !== 0 && !this.match(tokenTypes, channel)) {
-            this.get();
-        }
-
-        return this.LA(0);
-    },
-
-    /**
-     * Consumes the next token from the token stream.
-     * @return {int} The token type of the token that was just consumed.
-     * @method get
-     */
-    get: function(channel) {
-
-        var tokenInfo   = this._tokenData,
-            i           =0,
-            token,
-            info;
-
-        //check the lookahead buffer first
-        if (this._lt.length && this._ltIndex >= 0 && this._ltIndex < this._lt.length) {
-
-            i++;
-            this._token = this._lt[this._ltIndex++];
-            info = tokenInfo[this._token.type];
-
-            //obey channels logic
-            while ((info.channel !== undefined && channel !== info.channel) &&
-                    this._ltIndex < this._lt.length) {
-                this._token = this._lt[this._ltIndex++];
-                info = tokenInfo[this._token.type];
-                i++;
-            }
-
-            //here be dragons
-            if ((info.channel === undefined || channel === info.channel) &&
-                    this._ltIndex <= this._lt.length) {
-                this._ltIndexCache.push(i);
-                return this._token.type;
-            }
-        }
-
-        //call token retriever method
-        token = this._getToken();
-
-        //if it should be hidden, don't save a token
-        if (token.type > -1 && !tokenInfo[token.type].hide) {
-
-            //apply token channel
-            token.channel = tokenInfo[token.type].channel;
-
-            //save for later
-            this._token = token;
-            this._lt.push(token);
-
-            //save space that will be moved (must be done before array is truncated)
-            this._ltIndexCache.push(this._lt.length - this._ltIndex + i);
-
-            //keep the buffer under 5 items
-            if (this._lt.length > 5) {
-                this._lt.shift();
-            }
-
-            //also keep the shift buffer under 5 items
-            if (this._ltIndexCache.length > 5) {
-                this._ltIndexCache.shift();
-            }
-
-            //update lookahead index
-            this._ltIndex = this._lt.length;
-        }
-
-        /*
-         * Skip to the next token if:
-         * 1. The token type is marked as hidden.
-         * 2. The token type has a channel specified and it isn't the current channel.
-         */
-        info = tokenInfo[token.type];
-        if (info &&
-                (info.hide ||
-                (info.channel !== undefined && channel !== info.channel))) {
-            return this.get(channel);
-        } else {
-            //return just the type
-            return token.type;
-        }
-    },
-
-    /**
-     * Looks ahead a certain number of tokens and returns the token type at
-     * that position. This will throw an error if you lookahead past the
-     * end of input, past the size of the lookahead buffer, or back past
-     * the first token in the lookahead buffer.
-     * @param {int} The index of the token type to retrieve. 0 for the
-     *      current token, 1 for the next, -1 for the previous, etc.
-     * @return {int} The token type of the token in the given position.
-     * @method LA
-     */
-    LA: function(index) {
-        var total = index,
-            tt;
-        if (index > 0) {
-            //TODO: Store 5 somewhere
-            if (index > 5) {
-                throw new Error("Too much lookahead.");
-            }
-
-            //get all those tokens
-            while (total) {
-                tt = this.get();
-                total--;
-            }
-
-            //unget all those tokens
-            while (total < index) {
-                this.unget();
-                total++;
-            }
-        } else if (index < 0) {
-
-            if (this._lt[this._ltIndex+index]) {
-                tt = this._lt[this._ltIndex+index].type;
-            } else {
-                throw new Error("Too much lookbehind.");
-            }
-
-        } else {
-            tt = this._token.type;
-        }
-
-        return tt;
-
-    },
-
-    /**
-     * Looks ahead a certain number of tokens and returns the token at
-     * that position. This will throw an error if you lookahead past the
-     * end of input, past the size of the lookahead buffer, or back past
-     * the first token in the lookahead buffer.
-     * @param {int} The index of the token type to retrieve. 0 for the
-     *      current token, 1 for the next, -1 for the previous, etc.
-     * @return {Object} The token of the token in the given position.
-     * @method LA
-     */
-    LT: function(index) {
-
-        //lookahead first to prime the token buffer
-        this.LA(index);
-
-        //now find the token, subtract one because _ltIndex is already at the next index
-        return this._lt[this._ltIndex+index-1];
-    },
-
-    /**
-     * Returns the token type for the next token in the stream without
-     * consuming it.
-     * @return {int} The token type of the next token in the stream.
-     * @method peek
-     */
-    peek: function() {
-        return this.LA(1);
-    },
-
-    /**
-     * Returns the actual token object for the last consumed token.
-     * @return {Token} The token object for the last consumed token.
-     * @method token
-     */
-    token: function() {
-        return this._token;
-    },
-
-    /**
-     * Returns the name of the token for the given token type.
-     * @param {int} tokenType The type of token to get the name of.
-     * @return {String} The name of the token or "UNKNOWN_TOKEN" for any
-     *      invalid token type.
-     * @method tokenName
-     */
-    tokenName: function(tokenType) {
-        if (tokenType < 0 || tokenType > this._tokenData.length) {
-            return "UNKNOWN_TOKEN";
-        } else {
-            return this._tokenData[tokenType].name;
-        }
-    },
-
-    /**
-     * Returns the token type value for the given token name.
-     * @param {String} tokenName The name of the token whose value should be returned.
-     * @return {int} The token type value for the given token name or -1
-     *      for an unknown token.
-     * @method tokenName
-     */
-    tokenType: function(tokenName) {
-        return this._tokenData[tokenName] || -1;
-    },
-
-    /**
-     * Returns the last consumed token to the token stream.
-     * @method unget
-     */
-    unget: function() {
-        //if (this._ltIndex > -1) {
-        if (this._ltIndexCache.length) {
-            this._ltIndex -= this._ltIndexCache.pop();//--;
-            this._token = this._lt[this._ltIndex - 1];
-        } else {
-            throw new Error("Too much lookahead.");
-        }
-    }
-
-};
-
-
-},{"./StringReader":24,"./SyntaxError":25}],28:[function(require,module,exports){
-"use strict";
-
-module.exports = {
-    StringReader    : require("./StringReader"),
-    SyntaxError     : require("./SyntaxError"),
-    SyntaxUnit      : require("./SyntaxUnit"),
-    EventTarget     : require("./EventTarget"),
-    TokenStreamBase : require("./TokenStreamBase")
-};
-
-},{"./EventTarget":23,"./StringReader":24,"./SyntaxError":25,"./SyntaxUnit":26,"./TokenStreamBase":27}],"parserlib":[function(require,module,exports){
-"use strict";
-
-module.exports = {
-    css  : require("./css"),
-    util : require("./util")
-};
-
-},{"./css":22,"./util":28}]},{},[]);
-
-return require('parserlib');
-})();
-var clone = (function() {
-'use strict';
-
-var nativeMap;
-try {
-  nativeMap = Map;
-} catch(_) {
-  // maybe a reference error because no `Map`. Give it a dummy value that no
-  // value will ever be an instanceof.
-  nativeMap = function() {};
-}
-
-var nativeSet;
-try {
-  nativeSet = Set;
-} catch(_) {
-  nativeSet = function() {};
-}
-
-var nativePromise;
-try {
-  nativePromise = Promise;
-} catch(_) {
-  nativePromise = function() {};
-}
-
-/**
- * Clones (copies) an Object using deep copying.
- *
- * This function supports circular references by default, but if you are certain
- * there are no circular references in your object, you can save some CPU time
- * by calling clone(obj, false).
- *
- * Caution: if `circular` is false and `parent` contains circular references,
- * your program may enter an infinite loop and crash.
- *
- * @param `parent` - the object to be cloned
- * @param `circular` - set to true if the object to be cloned may contain
- *    circular references. (optional - true by default)
- * @param `depth` - set to a number if the object is only to be cloned to
- *    a particular depth. (optional - defaults to Infinity)
- * @param `prototype` - sets the prototype to be used when cloning an object.
- *    (optional - defaults to parent prototype).
- * @param `includeNonEnumerable` - set to true if the non-enumerable properties
- *    should be cloned as well. Non-enumerable properties on the prototype
- *    chain will be ignored. (optional - false by default)
-*/
-function clone(parent, circular, depth, prototype, includeNonEnumerable) {
-  if (typeof circular === 'object') {
-    depth = circular.depth;
-    prototype = circular.prototype;
-    includeNonEnumerable = circular.includeNonEnumerable;
-    circular = circular.circular;
-  }
-  // maintain two arrays for circular references, where corresponding parents
-  // and children have the same index
-  var allParents = [];
-  var allChildren = [];
-
-  var useBuffer = typeof Buffer != 'undefined';
-
-  if (typeof circular == 'undefined')
-    circular = true;
-
-  if (typeof depth == 'undefined')
-    depth = Infinity;
-
-  // recurse this function so we don't reset allParents and allChildren
-  function _clone(parent, depth) {
-    // cloning null always returns null
-    if (parent === null)
-      return null;
-
-    if (depth === 0)
-      return parent;
-
-    var child;
-    var proto;
-    if (typeof parent != 'object') {
-      return parent;
-    }
-
-    if (parent instanceof nativeMap) {
-      child = new nativeMap();
-    } else if (parent instanceof nativeSet) {
-      child = new nativeSet();
-    } else if (parent instanceof nativePromise) {
-      child = new nativePromise(function (resolve, reject) {
-        parent.then(function(value) {
-          resolve(_clone(value, depth - 1));
-        }, function(err) {
-          reject(_clone(err, depth - 1));
-        });
-      });
-    } else if (clone.__isArray(parent)) {
-      child = [];
-    } else if (clone.__isRegExp(parent)) {
-      child = new RegExp(parent.source, __getRegExpFlags(parent));
-      if (parent.lastIndex) child.lastIndex = parent.lastIndex;
-    } else if (clone.__isDate(parent)) {
-      child = new Date(parent.getTime());
-    } else if (useBuffer && Buffer.isBuffer(parent)) {
-      child = new Buffer(parent.length);
-      parent.copy(child);
-      return child;
-    } else if (parent instanceof Error) {
-      child = Object.create(parent);
-    } else {
-      if (typeof prototype == 'undefined') {
-        proto = Object.getPrototypeOf(parent);
-        child = Object.create(proto);
-      }
-      else {
-        child = Object.create(prototype);
-        proto = prototype;
-      }
-    }
-
-    if (circular) {
-      var index = allParents.indexOf(parent);
-
-      if (index != -1) {
-        return allChildren[index];
-      }
-      allParents.push(parent);
-      allChildren.push(child);
-    }
-
-    if (parent instanceof nativeMap) {
-      var keyIterator = parent.keys();
-      while(true) {
-        var next = keyIterator.next();
-        if (next.done) {
-          break;
-        }
-        var keyChild = _clone(next.value, depth - 1);
-        var valueChild = _clone(parent.get(next.value), depth - 1);
-        child.set(keyChild, valueChild);
-      }
-    }
-    if (parent instanceof nativeSet) {
-      var iterator = parent.keys();
-      while(true) {
-        var next = iterator.next();
-        if (next.done) {
-          break;
-        }
-        var entryChild = _clone(next.value, depth - 1);
-        child.add(entryChild);
-      }
-    }
-
-    for (var i in parent) {
-      var attrs;
-      if (proto) {
-        attrs = Object.getOwnPropertyDescriptor(proto, i);
-      }
-
-      if (attrs && attrs.set == null) {
-        continue;
-      }
-      child[i] = _clone(parent[i], depth - 1);
-    }
-
-    if (Object.getOwnPropertySymbols) {
-      var symbols = Object.getOwnPropertySymbols(parent);
-      for (var i = 0; i < symbols.length; i++) {
-        // Don't need to worry about cloning a symbol because it is a primitive,
-        // like a number or string.
-        var symbol = symbols[i];
-        var descriptor = Object.getOwnPropertyDescriptor(parent, symbol);
-        if (descriptor && !descriptor.enumerable && !includeNonEnumerable) {
-          continue;
-        }
-        child[symbol] = _clone(parent[symbol], depth - 1);
-        if (!descriptor.enumerable) {
-          Object.defineProperty(child, symbol, {
-            enumerable: false
-          });
-        }
-      }
-    }
-
-    if (includeNonEnumerable) {
-      var allPropertyNames = Object.getOwnPropertyNames(parent);
-      for (var i = 0; i < allPropertyNames.length; i++) {
-        var propertyName = allPropertyNames[i];
-        var descriptor = Object.getOwnPropertyDescriptor(parent, propertyName);
-        if (descriptor && descriptor.enumerable) {
-          continue;
-        }
-        child[propertyName] = _clone(parent[propertyName], depth - 1);
-        Object.defineProperty(child, propertyName, {
-          enumerable: false
-        });
-      }
-    }
-
-    return child;
-  }
-
-  return _clone(parent, depth);
-}
-
-/**
- * Simple flat clone using prototype, accepts only objects, usefull for property
- * override on FLAT configuration object (no nested props).
- *
- * USE WITH CAUTION! This may not behave as you wish if you do not know how this
- * works.
- */
-clone.clonePrototype = function clonePrototype(parent) {
-  if (parent === null)
-    return null;
-
-  var c = function () {};
-  c.prototype = parent;
-  return new c();
-};
-
-// private utility functions
-
-function __objToStr(o) {
-  return Object.prototype.toString.call(o);
-}
-clone.__objToStr = __objToStr;
-
-function __isDate(o) {
-  return typeof o === 'object' && __objToStr(o) === '[object Date]';
-}
-clone.__isDate = __isDate;
-
-function __isArray(o) {
-  return typeof o === 'object' && __objToStr(o) === '[object Array]';
-}
-clone.__isArray = __isArray;
-
-function __isRegExp(o) {
-  return typeof o === 'object' && __objToStr(o) === '[object RegExp]';
-}
-clone.__isRegExp = __isRegExp;
-
-function __getRegExpFlags(re) {
-  var flags = '';
-  if (re.global) flags += 'g';
-  if (re.ignoreCase) flags += 'i';
-  if (re.multiline) flags += 'm';
-  return flags;
-}
-clone.__getRegExpFlags = __getRegExpFlags;
-
-return clone;
-})();
-
-if (typeof module === 'object' && module.exports) {
-  module.exports = clone;
-}
-
-/**
- * Main CSSLint object.
- * @class CSSLint
- * @static
- * @extends parserlib.util.EventTarget
- */
-
-/* global parserlib, clone, Reporter */
-/* exported CSSLint */
-
-var CSSLint = (function() {
-    "use strict";
-
-    var rules           = [],
-        formatters      = [],
-        embeddedRuleset = /\/\*\s*csslint([^\*]*)\*\//,
-        api             = new parserlib.util.EventTarget();
-
-    api.version = "1.0.4";
-
-    //-------------------------------------------------------------------------
-    // Rule Management
-    //-------------------------------------------------------------------------
-
-    /**
-     * Adds a new rule to the engine.
-     * @param {Object} rule The rule to add.
-     * @method addRule
-     */
-    api.addRule = function(rule) {
-        rules.push(rule);
-        rules[rule.id] = rule;
-    };
-
-    /**
-     * Clears all rule from the engine.
-     * @method clearRules
-     */
-    api.clearRules = function() {
-        rules = [];
-    };
-
-    /**
-     * Returns the rule objects.
-     * @return An array of rule objects.
-     * @method getRules
-     */
-    api.getRules = function() {
-        return [].concat(rules).sort(function(a, b) {
-            return a.id > b.id ? 1 : 0;
-        });
-    };
-
-    /**
-     * Returns a ruleset configuration object with all current rules.
-     * @return A ruleset object.
-     * @method getRuleset
-     */
-    api.getRuleset = function() {
-        var ruleset = {},
-            i = 0,
-            len = rules.length;
-
-        while (i < len) {
-            ruleset[rules[i++].id] = 1;    // by default, everything is a warning
-        }
-
-        return ruleset;
-    };
-
-    /**
-     * Returns a ruleset object based on embedded rules.
-     * @param {String} text A string of css containing embedded rules.
-     * @param {Object} ruleset A ruleset object to modify.
-     * @return {Object} A ruleset object.
-     * @method getEmbeddedRuleset
-     */
-    function applyEmbeddedRuleset(text, ruleset) {
-        var valueMap,
-            embedded = text && text.match(embeddedRuleset),
-            rules = embedded && embedded[1];
-
-        if (rules) {
-            valueMap = {
-                "true": 2,  // true is error
-                "": 1,      // blank is warning
-                "false": 0, // false is ignore
-
-                "2": 2,     // explicit error
-                "1": 1,     // explicit warning
-                "0": 0      // explicit ignore
-            };
-
-            rules.toLowerCase().split(",").forEach(function(rule) {
-                var pair = rule.split(":"),
-                    property = pair[0] || "",
-                    value = pair[1] || "";
-
-                ruleset[property.trim()] = valueMap[value.trim()];
-            });
-        }
-
-        return ruleset;
-    }
-
-    //-------------------------------------------------------------------------
-    // Formatters
-    //-------------------------------------------------------------------------
-
-    /**
-     * Adds a new formatter to the engine.
-     * @param {Object} formatter The formatter to add.
-     * @method addFormatter
-     */
-    api.addFormatter = function(formatter) {
-        // formatters.push(formatter);
-        formatters[formatter.id] = formatter;
-    };
-
-    /**
-     * Retrieves a formatter for use.
-     * @param {String} formatId The name of the format to retrieve.
-     * @return {Object} The formatter or undefined.
-     * @method getFormatter
-     */
-    api.getFormatter = function(formatId) {
-        return formatters[formatId];
-    };
-
-    /**
-     * Formats the results in a particular format for a single file.
-     * @param {Object} result The results returned from CSSLint.verify().
-     * @param {String} filename The filename for which the results apply.
-     * @param {String} formatId The name of the formatter to use.
-     * @param {Object} options (Optional) for special output handling.
-     * @return {String} A formatted string for the results.
-     * @method format
-     */
-    api.format = function(results, filename, formatId, options) {
-        var formatter = this.getFormatter(formatId),
-            result = null;
-
-        if (formatter) {
-            result = formatter.startFormat();
-            result += formatter.formatResults(results, filename, options || {});
-            result += formatter.endFormat();
-        }
-
-        return result;
-    };
-
-    /**
-     * Indicates if the given format is supported.
-     * @param {String} formatId The ID of the format to check.
-     * @return {Boolean} True if the format exists, false if not.
-     * @method hasFormat
-     */
-    api.hasFormat = function(formatId) {
-        return formatters.hasOwnProperty(formatId);
-    };
-
-    //-------------------------------------------------------------------------
-    // Verification
-    //-------------------------------------------------------------------------
-
-    /**
-     * Starts the verification process for the given CSS text.
-     * @param {String} text The CSS text to verify.
-     * @param {Object} ruleset (Optional) List of rules to apply. If null, then
-     *      all rules are used. If a rule has a value of 1 then it's a warning,
-     *      a value of 2 means it's an error.
-     * @return {Object} Results of the verification.
-     * @method verify
-     */
-    api.verify = function(text, ruleset) {
-
-        var i = 0,
-            reporter,
-            lines,
-            allow = {},
-            ignore = [],
-            report,
-            parser = new parserlib.css.Parser({
-                starHack: true,
-                ieFilters: true,
-                underscoreHack: true,
-                strict: false
-            });
-
-        // normalize line endings
-        lines = text.replace(/\n\r?/g, "$split$").split("$split$");
-
-        // find 'allow' comments
-        CSSLint.Util.forEach(lines, function (line, lineno) {
-            var allowLine = line && line.match(/\/\*[ \t]*csslint[ \t]+allow:[ \t]*([^\*]*)\*\//i),
-                allowRules = allowLine && allowLine[1],
-                allowRuleset = {};
-
-            if (allowRules) {
-                allowRules.toLowerCase().split(",").forEach(function(allowRule) {
-                    allowRuleset[allowRule.trim()] = true;
-                });
-                if (Object.keys(allowRuleset).length > 0) {
-                    allow[lineno + 1] = allowRuleset;
-                }
-            }
-        });
-
-        var ignoreStart = null,
-            ignoreEnd = null;
-        CSSLint.Util.forEach(lines, function (line, lineno) {
-            // Keep oldest, "unclosest" ignore:start
-            if (ignoreStart === null && line.match(/\/\*[ \t]*csslint[ \t]+ignore:start[ \t]*\*\//i)) {
-                ignoreStart = lineno;
-            }
-
-            if (line.match(/\/\*[ \t]*csslint[ \t]+ignore:end[ \t]*\*\//i)) {
-                ignoreEnd = lineno;
-            }
-
-            if (ignoreStart !== null && ignoreEnd !== null) {
-                ignore.push([ignoreStart, ignoreEnd]);
-                ignoreStart = ignoreEnd = null;
-            }
-        });
-
-        // Close remaining ignore block, if any
-        if (ignoreStart !== null) {
-            ignore.push([ignoreStart, lines.length]);
-        }
-
-        if (!ruleset) {
-            ruleset = this.getRuleset();
-        }
-
-        if (embeddedRuleset.test(text)) {
-            // defensively copy so that caller's version does not get modified
-            ruleset = clone(ruleset);
-            ruleset = applyEmbeddedRuleset(text, ruleset);
-        }
-
-        reporter = new Reporter(lines, ruleset, allow, ignore);
-
-        ruleset.errors = 2;       // always report parsing errors as errors
-        for (i in ruleset) {
-            if (ruleset.hasOwnProperty(i) && ruleset[i]) {
-                if (rules[i]) {
-                    rules[i].init(parser, reporter);
-                }
-            }
-        }
-
-
-        // capture most horrible error type
-        try {
-            parser.parse(text);
-        } catch (ex) {
-            reporter.error("Fatal error, cannot continue: " + ex.message, ex.line, ex.col, {});
-        }
-
-        report = {
-            messages    : reporter.messages,
-            stats       : reporter.stats,
-            ruleset     : reporter.ruleset,
-            allow       : reporter.allow,
-            ignore      : reporter.ignore
-        };
-
-        // sort by line numbers, rollups at the bottom
-        report.messages.sort(function (a, b) {
-            if (a.rollup && !b.rollup) {
-                return 1;
-            } else if (!a.rollup && b.rollup) {
-                return -1;
-            } else {
-                return a.line - b.line;
-            }
-        });
-
-        return report;
-    };
-
-    //-------------------------------------------------------------------------
-    // Publish the API
-    //-------------------------------------------------------------------------
-
-    return api;
-
-})();
-
-/**
- * An instance of Report is used to report results of the
- * verification back to the main API.
- * @class Reporter
- * @constructor
- * @param {String[]} lines The text lines of the source.
- * @param {Object} ruleset The set of rules to work with, including if
- *      they are errors or warnings.
- * @param {Object} explicitly allowed lines
- * @param {[][]} ingore list of line ranges to be ignored
- */
-function Reporter(lines, ruleset, allow, ignore) {
-    "use strict";
-
-    /**
-     * List of messages being reported.
-     * @property messages
-     * @type String[]
-     */
-    this.messages = [];
-
-    /**
-     * List of statistics being reported.
-     * @property stats
-     * @type String[]
-     */
-    this.stats = [];
-
-    /**
-     * Lines of code being reported on. Used to provide contextual information
-     * for messages.
-     * @property lines
-     * @type String[]
-     */
-    this.lines = lines;
-
-    /**
-     * Information about the rules. Used to determine whether an issue is an
-     * error or warning.
-     * @property ruleset
-     * @type Object
-     */
-    this.ruleset = ruleset;
-
-    /**
-     * Lines with specific rule messages to leave out of the report.
-     * @property allow
-     * @type Object
-     */
-    this.allow = allow;
-    if (!this.allow) {
-        this.allow = {};
-    }
-
-    /**
-     * Linesets not to include in the report.
-     * @property ignore
-     * @type [][]
-     */
-    this.ignore = ignore;
-    if (!this.ignore) {
-        this.ignore = [];
-    }
-}
-
-Reporter.prototype = {
-
-    // restore constructor
-    constructor: Reporter,
-
-    /**
-     * Report an error.
-     * @param {String} message The message to store.
-     * @param {int} line The line number.
-     * @param {int} col The column number.
-     * @param {Object} rule The rule this message relates to.
-     * @method error
-     */
-    error: function(message, line, col, rule) {
-        "use strict";
-        this.messages.push({
-            type    : "error",
-            line    : line,
-            col     : col,
-            message : message,
-            evidence: this.lines[line-1],
-            rule    : rule || {}
-        });
-    },
-
-    /**
-     * Report an warning.
-     * @param {String} message The message to store.
-     * @param {int} line The line number.
-     * @param {int} col The column number.
-     * @param {Object} rule The rule this message relates to.
-     * @method warn
-     * @deprecated Use report instead.
-     */
-    warn: function(message, line, col, rule) {
-        "use strict";
-        this.report(message, line, col, rule);
-    },
-
-    /**
-     * Report an issue.
-     * @param {String} message The message to store.
-     * @param {int} line The line number.
-     * @param {int} col The column number.
-     * @param {Object} rule The rule this message relates to.
-     * @method report
-     */
-    report: function(message, line, col, rule) {
-        "use strict";
-
-        // Check if rule violation should be allowed
-        if (this.allow.hasOwnProperty(line) && this.allow[line].hasOwnProperty(rule.id)) {
-            return;
-        }
-
-        var ignore = false;
-        CSSLint.Util.forEach(this.ignore, function (range) {
-            if (range[0] <= line && line <= range[1]) {
-                ignore = true;
-            }
-        });
-        if (ignore) {
-            return;
-        }
-
-        this.messages.push({
-            type    : this.ruleset[rule.id] === 2 ? "error" : "warning",
-            line    : line,
-            col     : col,
-            message : message,
-            evidence: this.lines[line-1],
-            rule    : rule
-        });
-    },
-
-    /**
-     * Report some informational text.
-     * @param {String} message The message to store.
-     * @param {int} line The line number.
-     * @param {int} col The column number.
-     * @param {Object} rule The rule this message relates to.
-     * @method info
-     */
-    info: function(message, line, col, rule) {
-        "use strict";
-        this.messages.push({
-            type    : "info",
-            line    : line,
-            col     : col,
-            message : message,
-            evidence: this.lines[line-1],
-            rule    : rule
-        });
-    },
-
-    /**
-     * Report some rollup error information.
-     * @param {String} message The message to store.
-     * @param {Object} rule The rule this message relates to.
-     * @method rollupError
-     */
-    rollupError: function(message, rule) {
-        "use strict";
-        this.messages.push({
-            type    : "error",
-            rollup  : true,
-            message : message,
-            rule    : rule
-        });
-    },
-
-    /**
-     * Report some rollup warning information.
-     * @param {String} message The message to store.
-     * @param {Object} rule The rule this message relates to.
-     * @method rollupWarn
-     */
-    rollupWarn: function(message, rule) {
-        "use strict";
-        this.messages.push({
-            type    : "warning",
-            rollup  : true,
-            message : message,
-            rule    : rule
-        });
-    },
-
-    /**
-     * Report a statistic.
-     * @param {String} name The name of the stat to store.
-     * @param {Variant} value The value of the stat.
-     * @method stat
-     */
-    stat: function(name, value) {
-        "use strict";
-        this.stats[name] = value;
-    }
-};
-
-// expose for testing purposes
-CSSLint._Reporter = Reporter;
-
-/*
- * Utility functions that make life easier.
- */
-CSSLint.Util = {
-    /*
-     * Adds all properties from supplier onto receiver,
-     * overwriting if the same name already exists on
-     * receiver.
-     * @param {Object} The object to receive the properties.
-     * @param {Object} The object to provide the properties.
-     * @return {Object} The receiver
-     */
-    mix: function(receiver, supplier) {
-        "use strict";
-        var prop;
-
-        for (prop in supplier) {
-            if (supplier.hasOwnProperty(prop)) {
-                receiver[prop] = supplier[prop];
-            }
-        }
-
-        return prop;
-    },
-
-    /*
-     * Polyfill for array indexOf() method.
-     * @param {Array} values The array to search.
-     * @param {Variant} value The value to search for.
-     * @return {int} The index of the value if found, -1 if not.
-     */
-    indexOf: function(values, value) {
-        "use strict";
-        if (values.indexOf) {
-            return values.indexOf(value);
-        } else {
-            for (var i=0, len=values.length; i < len; i++) {
-                if (values[i] === value) {
-                    return i;
-                }
-            }
-            return -1;
-        }
-    },
-
-    /*
-     * Polyfill for array forEach() method.
-     * @param {Array} values The array to operate on.
-     * @param {Function} func The function to call on each item.
-     * @return {void}
-     */
-    forEach: function(values, func) {
-        "use strict";
-        if (values.forEach) {
-            return values.forEach(func);
-        } else {
-            for (var i=0, len=values.length; i < len; i++) {
-                func(values[i], i, values);
-            }
-        }
-    }
-};
-
-/*
- * Rule: Don't use adjoining classes (.foo.bar).
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "adjoining-classes",
-    name: "Disallow adjoining classes",
-    desc: "Don't use adjoining classes.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-adjoining-classes",
-    browsers: "IE6",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-        parser.addListener("startrule", function(event) {
-            var selectors = event.selectors,
-                selector,
-                part,
-                modifier,
-                classCount,
-                i, j, k;
-
-            for (i=0; i < selectors.length; i++) {
-                selector = selectors[i];
-                for (j=0; j < selector.parts.length; j++) {
-                    part = selector.parts[j];
-                    if (part.type === parser.SELECTOR_PART_TYPE) {
-                        classCount = 0;
-                        for (k=0; k < part.modifiers.length; k++) {
-                            modifier = part.modifiers[k];
-                            if (modifier.type === "class") {
-                                classCount++;
-                            }
-                            if (classCount > 1){
-                                reporter.report("Adjoining classes: "+selectors[i].text, part.line, part.col, rule);
-                            }
-                        }
-                    }
-                }
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Don't use width or height when using padding or border.
- */
-CSSLint.addRule({
-
-    // rule information
-    id: "box-model",
-    name: "Beware of broken box size",
-    desc: "Don't use width or height when using padding or border.",
-    url: "https://github.com/CSSLint/csslint/wiki/Beware-of-box-model-size",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            widthProperties = {
-                border: 1,
-                "border-left": 1,
-                "border-right": 1,
-                padding: 1,
-                "padding-left": 1,
-                "padding-right": 1
-            },
-            heightProperties = {
-                border: 1,
-                "border-bottom": 1,
-                "border-top": 1,
-                padding: 1,
-                "padding-bottom": 1,
-                "padding-top": 1
-            },
-            properties,
-            boxSizing = false;
-
-        function startRule() {
-            properties = {};
-            boxSizing = false;
-        }
-
-        function endRule() {
-            var prop, value;
-
-            if (!boxSizing) {
-                if (properties.height) {
-                    for (prop in heightProperties) {
-                        if (heightProperties.hasOwnProperty(prop) && properties[prop]) {
-                            value = properties[prop].value;
-                            // special case for padding
-                            if (!(prop === "padding" && value.parts.length === 2 && value.parts[0].value === 0)) {
-                                reporter.report("Using height with " + prop + " can sometimes make elements larger than you expect.", properties[prop].line, properties[prop].col, rule);
-                            }
-                        }
-                    }
-                }
-
-                if (properties.width) {
-                    for (prop in widthProperties) {
-                        if (widthProperties.hasOwnProperty(prop) && properties[prop]) {
-                            value = properties[prop].value;
-
-                            if (!(prop === "padding" && value.parts.length === 2 && value.parts[1].value === 0)) {
-                                reporter.report("Using width with " + prop + " can sometimes make elements larger than you expect.", properties[prop].line, properties[prop].col, rule);
-                            }
-                        }
-                    }
-                }
-            }
-        }
-
-        parser.addListener("startrule", startRule);
-        parser.addListener("startfontface", startRule);
-        parser.addListener("startpage", startRule);
-        parser.addListener("startpagemargin", startRule);
-        parser.addListener("startkeyframerule", startRule);
-        parser.addListener("startviewport", startRule);
-
-        parser.addListener("property", function(event) {
-            var name = event.property.text.toLowerCase();
-
-            if (heightProperties[name] || widthProperties[name]) {
-                if (!/^0\S*$/.test(event.value) && !(name === "border" && event.value.toString() === "none")) {
-                    properties[name] = {
-                        line: event.property.line,
-                        col: event.property.col,
-                        value: event.value
-                    };
-                }
-            } else {
-                if (/^(width|height)/i.test(name) && /^(length|percentage)/.test(event.value.parts[0].type)) {
-                    properties[name] = 1;
-                } else if (name === "box-sizing") {
-                    boxSizing = true;
-                }
-            }
-
-        });
-
-        parser.addListener("endrule", endRule);
-        parser.addListener("endfontface", endRule);
-        parser.addListener("endpage", endRule);
-        parser.addListener("endpagemargin", endRule);
-        parser.addListener("endkeyframerule", endRule);
-        parser.addListener("endviewport", endRule);
-    }
-
-});
-
-/*
- * Rule: box-sizing doesn't work in IE6 and IE7.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "box-sizing",
-    name: "Disallow use of box-sizing",
-    desc: "The box-sizing properties isn't supported in IE6 and IE7.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-box-sizing",
-    browsers: "IE6, IE7",
-    tags: ["Compatibility"],
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        parser.addListener("property", function(event) {
-            var name = event.property.text.toLowerCase();
-
-            if (name === "box-sizing") {
-                reporter.report("The box-sizing property isn't supported in IE6 and IE7.", event.line, event.col, rule);
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Use the bulletproof @font-face syntax to avoid 404's in old IE
- * (http://www.fontspring.com/blog/the-new-bulletproof-font-face-syntax)
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "bulletproof-font-face",
-    name: "Use the bulletproof @font-face syntax",
-    desc: "Use the bulletproof @font-face syntax to avoid 404's in old IE (http://www.fontspring.com/blog/the-new-bulletproof-font-face-syntax).",
-    url: "https://github.com/CSSLint/csslint/wiki/Bulletproof-font-face",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            fontFaceRule = false,
-            firstSrc = true,
-            ruleFailed = false,
-            line, col;
-
-        // Mark the start of a @font-face declaration so we only test properties inside it
-        parser.addListener("startfontface", function() {
-            fontFaceRule = true;
-        });
-
-        parser.addListener("property", function(event) {
-            // If we aren't inside an @font-face declaration then just return
-            if (!fontFaceRule) {
-                return;
-            }
-
-            var propertyName = event.property.toString().toLowerCase(),
-                value = event.value.toString();
-
-            // Set the line and col numbers for use in the endfontface listener
-            line = event.line;
-            col = event.col;
-
-            // This is the property that we care about, we can ignore the rest
-            if (propertyName === "src") {
-                var regex = /^\s?url\(['"].+\.eot\?.*['"]\)\s*format\(['"]embedded-opentype['"]\).*$/i;
-
-                // We need to handle the advanced syntax with two src properties
-                if (!value.match(regex) && firstSrc) {
-                    ruleFailed = true;
-                    firstSrc = false;
-                } else if (value.match(regex) && !firstSrc) {
-                    ruleFailed = false;
-                }
-            }
-
-
-        });
-
-        // Back to normal rules that we don't need to test
-        parser.addListener("endfontface", function() {
-            fontFaceRule = false;
-
-            if (ruleFailed) {
-                reporter.report("@font-face declaration doesn't follow the fontspring bulletproof syntax.", line, col, rule);
-            }
-        });
-    }
-});
-
-/*
- * Rule: Include all compatible vendor prefixes to reach a wider
- * range of users.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "compatible-vendor-prefixes",
-    name: "Require compatible vendor prefixes",
-    desc: "Include all compatible vendor prefixes to reach a wider range of users.",
-    url: "https://github.com/CSSLint/csslint/wiki/Require-compatible-vendor-prefixes",
-    browsers: "All",
-
-    // initialization
-    init: function (parser, reporter) {
-        "use strict";
-        var rule = this,
-            compatiblePrefixes,
-            properties,
-            prop,
-            variations,
-            prefixed,
-            i,
-            len,
-            inKeyFrame = false,
-            arrayPush = Array.prototype.push,
-            applyTo = [];
-
-        // See http://peter.sh/experiments/vendor-prefixed-css-property-overview/ for details
-        compatiblePrefixes = {
-            "animation"                  : "webkit",
-            "animation-delay"            : "webkit",
-            "animation-direction"        : "webkit",
-            "animation-duration"         : "webkit",
-            "animation-fill-mode"        : "webkit",
-            "animation-iteration-count"  : "webkit",
-            "animation-name"             : "webkit",
-            "animation-play-state"       : "webkit",
-            "animation-timing-function"  : "webkit",
-            "appearance"                 : "webkit moz",
-            "border-end"                 : "webkit moz",
-            "border-end-color"           : "webkit moz",
-            "border-end-style"           : "webkit moz",
-            "border-end-width"           : "webkit moz",
-            "border-image"               : "webkit moz o",
-            "border-radius"              : "webkit",
-            "border-start"               : "webkit moz",
-            "border-start-color"         : "webkit moz",
-            "border-start-style"         : "webkit moz",
-            "border-start-width"         : "webkit moz",
-            "box-align"                  : "webkit moz",
-            "box-direction"              : "webkit moz",
-            "box-flex"                   : "webkit moz",
-            "box-lines"                  : "webkit",
-            "box-ordinal-group"          : "webkit moz",
-            "box-orient"                 : "webkit moz",
-            "box-pack"                   : "webkit moz",
-            "box-sizing"                 : "",
-            "box-shadow"                 : "",
-            "column-count"               : "webkit moz ms",
-            "column-gap"                 : "webkit moz ms",
-            "column-rule"                : "webkit moz ms",
-            "column-rule-color"          : "webkit moz ms",
-            "column-rule-style"          : "webkit moz ms",
-            "column-rule-width"          : "webkit moz ms",
-            "column-width"               : "webkit moz ms",
-            "flex"                       : "webkit ms",
-            "flex-basis"                 : "webkit",
-            "flex-direction"             : "webkit ms",
-            "flex-flow"                  : "webkit",
-            "flex-grow"                  : "webkit",
-            "flex-shrink"                : "webkit",
-            "hyphens"                    : "epub moz",
-            "line-break"                 : "webkit ms",
-            "margin-end"                 : "webkit moz",
-            "margin-start"               : "webkit moz",
-            "marquee-speed"              : "webkit wap",
-            "marquee-style"              : "webkit wap",
-            "padding-end"                : "webkit moz",
-            "padding-start"              : "webkit moz",
-            "tab-size"                   : "moz o",
-            "text-size-adjust"           : "webkit ms",
-            "transform"                  : "webkit ms",
-            "transform-origin"           : "webkit ms",
-            "transition"                 : "",
-            "transition-delay"           : "",
-            "transition-duration"        : "",
-            "transition-property"        : "",
-            "transition-timing-function" : "",
-            "user-modify"                : "webkit moz",
-            "user-select"                : "webkit moz ms",
-            "word-break"                 : "epub ms",
-            "writing-mode"               : "epub ms"
-        };
-
-
-        for (prop in compatiblePrefixes) {
-            if (compatiblePrefixes.hasOwnProperty(prop)) {
-                variations = [];
-                prefixed = compatiblePrefixes[prop].split(" ");
-                for (i = 0, len = prefixed.length; i < len; i++) {
-                    variations.push("-" + prefixed[i] + "-" + prop);
-                }
-                compatiblePrefixes[prop] = variations;
-                arrayPush.apply(applyTo, variations);
-            }
-        }
-
-        parser.addListener("startrule", function () {
-            properties = [];
-        });
-
-        parser.addListener("startkeyframes", function (event) {
-            inKeyFrame = event.prefix || true;
-        });
-
-        parser.addListener("endkeyframes", function () {
-            inKeyFrame = false;
-        });
-
-        parser.addListener("property", function (event) {
-            var name = event.property;
-            if (CSSLint.Util.indexOf(applyTo, name.text) > -1) {
-
-                // e.g., -moz-transform is okay to be alone in @-moz-keyframes
-                if (!inKeyFrame || typeof inKeyFrame !== "string" ||
-                        name.text.indexOf("-" + inKeyFrame + "-") !== 0) {
-                    properties.push(name);
-                }
-            }
-        });
-
-        parser.addListener("endrule", function () {
-            if (!properties.length) {
-                return;
-            }
-
-            var propertyGroups = {},
-                i,
-                len,
-                name,
-                prop,
-                variations,
-                value,
-                full,
-                actual,
-                item,
-                propertiesSpecified;
-
-            for (i = 0, len = properties.length; i < len; i++) {
-                name = properties[i];
-
-                for (prop in compatiblePrefixes) {
-                    if (compatiblePrefixes.hasOwnProperty(prop)) {
-                        variations = compatiblePrefixes[prop];
-                        if (CSSLint.Util.indexOf(variations, name.text) > -1) {
-                            if (!propertyGroups[prop]) {
-                                propertyGroups[prop] = {
-                                    full: variations.slice(0),
-                                    actual: [],
-                                    actualNodes: []
-                                };
-                            }
-                            if (CSSLint.Util.indexOf(propertyGroups[prop].actual, name.text) === -1) {
-                                propertyGroups[prop].actual.push(name.text);
-                                propertyGroups[prop].actualNodes.push(name);
-                            }
-                        }
-                    }
-                }
-            }
-
-            for (prop in propertyGroups) {
-                if (propertyGroups.hasOwnProperty(prop)) {
-                    value = propertyGroups[prop];
-                    full = value.full;
-                    actual = value.actual;
-
-                    if (full.length > actual.length) {
-                        for (i = 0, len = full.length; i < len; i++) {
-                            item = full[i];
-                            if (CSSLint.Util.indexOf(actual, item) === -1) {
-                                propertiesSpecified = (actual.length === 1) ? actual[0] : (actual.length === 2) ? actual.join(" and ") : actual.join(", ");
-                                reporter.report("The property " + item + " is compatible with " + propertiesSpecified + " and should be included as well.", value.actualNodes[0].line, value.actualNodes[0].col, rule);
-                            }
-                        }
-
-                    }
-                }
-            }
-        });
-    }
-});
-
-/*
- * Rule: Certain properties don't play well with certain display values.
- * - float should not be used with inline-block
- * - height, width, margin-top, margin-bottom, float should not be used with inline
- * - vertical-align should not be used with block
- * - margin, float should not be used with table-*
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "display-property-grouping",
-    name: "Require properties appropriate for display",
-    desc: "Certain properties shouldn't be used with certain display property values.",
-    url: "https://github.com/CSSLint/csslint/wiki/Require-properties-appropriate-for-display",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        var propertiesToCheck = {
-                display: 1,
-                "float": "none",
-                height: 1,
-                width: 1,
-                margin: 1,
-                "margin-left": 1,
-                "margin-right": 1,
-                "margin-bottom": 1,
-                "margin-top": 1,
-                padding: 1,
-                "padding-left": 1,
-                "padding-right": 1,
-                "padding-bottom": 1,
-                "padding-top": 1,
-                "vertical-align": 1
-            },
-            properties;
-
-        function reportProperty(name, display, msg) {
-            if (properties[name]) {
-                if (typeof propertiesToCheck[name] !== "string" || properties[name].value.toLowerCase() !== propertiesToCheck[name]) {
-                    reporter.report(msg || name + " can't be used with display: " + display + ".", properties[name].line, properties[name].col, rule);
-                }
-            }
-        }
-
-        function startRule() {
-            properties = {};
-        }
-
-        function endRule() {
-
-            var display = properties.display ? properties.display.value : null;
-            if (display) {
-                switch (display) {
-
-                    case "inline":
-                        // height, width, margin-top, margin-bottom, float should not be used with inline
-                        reportProperty("height", display);
-                        reportProperty("width", display);
-                        reportProperty("margin", display);
-                        reportProperty("margin-top", display);
-                        reportProperty("margin-bottom", display);
-                        reportProperty("float", display, "display:inline has no effect on floated elements (but may be used to fix the IE6 double-margin bug).");
-                        break;
-
-                    case "block":
-                        // vertical-align should not be used with block
-                        reportProperty("vertical-align", display);
-                        break;
-
-                    case "inline-block":
-                        // float should not be used with inline-block
-                        reportProperty("float", display);
-                        break;
-
-                    default:
-                        // margin, float should not be used with table
-                        if (display.indexOf("table-") === 0) {
-                            reportProperty("margin", display);
-                            reportProperty("margin-left", display);
-                            reportProperty("margin-right", display);
-                            reportProperty("margin-top", display);
-                            reportProperty("margin-bottom", display);
-                            reportProperty("float", display);
-                        }
-
-                        // otherwise do nothing
-                }
-            }
-
-        }
-
-        parser.addListener("startrule", startRule);
-        parser.addListener("startfontface", startRule);
-        parser.addListener("startkeyframerule", startRule);
-        parser.addListener("startpagemargin", startRule);
-        parser.addListener("startpage", startRule);
-        parser.addListener("startviewport", startRule);
-
-        parser.addListener("property", function(event) {
-            var name = event.property.text.toLowerCase();
-
-            if (propertiesToCheck[name]) {
-                properties[name] = {
-                    value: event.value.text,
-                    line: event.property.line,
-                    col: event.property.col
-                };
-            }
-        });
-
-        parser.addListener("endrule", endRule);
-        parser.addListener("endfontface", endRule);
-        parser.addListener("endkeyframerule", endRule);
-        parser.addListener("endpagemargin", endRule);
-        parser.addListener("endpage", endRule);
-        parser.addListener("endviewport", endRule);
-
-    }
-
-});
-
-/*
- * Rule: Disallow duplicate background-images (using url).
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "duplicate-background-images",
-    name: "Disallow duplicate background images",
-    desc: "Every background-image should be unique. Use a common class for e.g. sprites.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-duplicate-background-images",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            stack = {};
-
-        parser.addListener("property", function(event) {
-            var name = event.property.text,
-                value = event.value,
-                i, len;
-
-            if (name.match(/background/i)) {
-                for (i=0, len=value.parts.length; i < len; i++) {
-                    if (value.parts[i].type === "uri") {
-                        if (typeof stack[value.parts[i].uri] === "undefined") {
-                            stack[value.parts[i].uri] = event;
-                        } else {
-                            reporter.report("Background image '" + value.parts[i].uri + "' was used multiple times, first declared at line " + stack[value.parts[i].uri].line + ", col " + stack[value.parts[i].uri].col + ".", event.line, event.col, rule);
-                        }
-                    }
-                }
-            }
-        });
-    }
-});
-
-/*
- * Rule: Duplicate properties must appear one after the other. If an already-defined
- * property appears somewhere else in the rule, then it's likely an error.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "duplicate-properties",
-    name: "Disallow duplicate properties",
-    desc: "Duplicate properties must appear one after the other.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-duplicate-properties",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            properties,
-            lastProperty;
-
-        function startRule() {
-            properties = {};
-        }
-
-        parser.addListener("startrule", startRule);
-        parser.addListener("startfontface", startRule);
-        parser.addListener("startpage", startRule);
-        parser.addListener("startpagemargin", startRule);
-        parser.addListener("startkeyframerule", startRule);
-        parser.addListener("startviewport", startRule);
-
-        parser.addListener("property", function(event) {
-            var property = event.property,
-                name = property.text.toLowerCase();
-
-            if (properties[name] && (lastProperty !== name || properties[name] === event.value.text)) {
-                reporter.report("Duplicate property '" + event.property + "' found.", event.line, event.col, rule);
-            }
-
-            properties[name] = event.value.text;
-            lastProperty = name;
-
-        });
-
-
-    }
-
-});
-
-/*
- * Rule: Style rules without any properties defined should be removed.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "empty-rules",
-    name: "Disallow empty rules",
-    desc: "Rules without any properties specified should be removed.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-empty-rules",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            count = 0;
-
-        parser.addListener("startrule", function() {
-            count=0;
-        });
-
-        parser.addListener("property", function() {
-            count++;
-        });
-
-        parser.addListener("endrule", function(event) {
-            var selectors = event.selectors;
-            if (count === 0) {
-                reporter.report("Rule is empty.", selectors[0].line, selectors[0].col, rule);
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: There should be no syntax errors. (Duh.)
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "errors",
-    name: "Parsing Errors",
-    desc: "This rule looks for recoverable syntax errors.",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        parser.addListener("error", function(event) {
-            reporter.error(event.message, event.line, event.col, rule);
-        });
-
-    }
-
-});
-
-CSSLint.addRule({
-
-    // rule information
-    id: "fallback-colors",
-    name: "Require fallback colors",
-    desc: "For older browsers that don't support RGBA, HSL, or HSLA, provide a fallback color.",
-    url: "https://github.com/CSSLint/csslint/wiki/Require-fallback-colors",
-    browsers: "IE6,IE7,IE8",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            lastProperty,
-            propertiesToCheck = {
-                color: 1,
-                background: 1,
-                "border-color": 1,
-                "border-top-color": 1,
-                "border-right-color": 1,
-                "border-bottom-color": 1,
-                "border-left-color": 1,
-                border: 1,
-                "border-top": 1,
-                "border-right": 1,
-                "border-bottom": 1,
-                "border-left": 1,
-                "background-color": 1
-            };
-
-        function startRule() {
-            lastProperty = null;
-        }
-
-        parser.addListener("startrule", startRule);
-        parser.addListener("startfontface", startRule);
-        parser.addListener("startpage", startRule);
-        parser.addListener("startpagemargin", startRule);
-        parser.addListener("startkeyframerule", startRule);
-        parser.addListener("startviewport", startRule);
-
-        parser.addListener("property", function(event) {
-            var property = event.property,
-                name = property.text.toLowerCase(),
-                parts = event.value.parts,
-                i = 0,
-                colorType = "",
-                len = parts.length;
-
-            if (propertiesToCheck[name]) {
-                while (i < len) {
-                    if (parts[i].type === "color") {
-                        if ("alpha" in parts[i] || "hue" in parts[i]) {
-
-                            if (/([^\)]+)\(/.test(parts[i])) {
-                                colorType = RegExp.$1.toUpperCase();
-                            }
-
-                            if (!lastProperty || (lastProperty.property.text.toLowerCase() !== name || lastProperty.colorType !== "compat")) {
-                                reporter.report("Fallback " + name + " (hex or RGB) should precede " + colorType + " " + name + ".", event.line, event.col, rule);
-                            }
-                        } else {
-                            event.colorType = "compat";
-                        }
-                    }
-
-                    i++;
-                }
-            }
-
-            lastProperty = event;
-        });
-
-    }
-
-});
-
-/*
- * Rule: You shouldn't use more than 10 floats. If you do, there's probably
- * room for some abstraction.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "floats",
-    name: "Disallow too many floats",
-    desc: "This rule tests if the float property is used too many times",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-too-many-floats",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-        var count = 0;
-
-        // count how many times "float" is used
-        parser.addListener("property", function(event) {
-            if (event.property.text.toLowerCase() === "float" &&
-                    event.value.text.toLowerCase() !== "none") {
-                count++;
-            }
-        });
-
-        // report the results
-        parser.addListener("endstylesheet", function() {
-            reporter.stat("floats", count);
-            if (count >= 10) {
-                reporter.rollupWarn("Too many floats (" + count + "), you're probably using them for layout. Consider using a grid system instead.", rule);
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Avoid too many @font-face declarations in the same stylesheet.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "font-faces",
-    name: "Don't use too many web fonts",
-    desc: "Too many different web fonts in the same stylesheet.",
-    url: "https://github.com/CSSLint/csslint/wiki/Don%27t-use-too-many-web-fonts",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            count = 0;
-
-
-        parser.addListener("startfontface", function() {
-            count++;
-        });
-
-        parser.addListener("endstylesheet", function() {
-            if (count > 5) {
-                reporter.rollupWarn("Too many @font-face declarations (" + count + ").", rule);
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: You shouldn't need more than 9 font-size declarations.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "font-sizes",
-    name: "Disallow too many font sizes",
-    desc: "Checks the number of font-size declarations.",
-    url: "https://github.com/CSSLint/csslint/wiki/Don%27t-use-too-many-font-size-declarations",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            count = 0;
-
-        // check for use of "font-size"
-        parser.addListener("property", function(event) {
-            if (event.property.toString() === "font-size") {
-                count++;
-            }
-        });
-
-        // report the results
-        parser.addListener("endstylesheet", function() {
-            reporter.stat("font-sizes", count);
-            if (count >= 10) {
-                reporter.rollupWarn("Too many font-size declarations (" + count + "), abstraction needed.", rule);
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: When using a vendor-prefixed gradient, make sure to use them all.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "gradients",
-    name: "Require all gradient definitions",
-    desc: "When using a vendor-prefixed gradient, make sure to use them all.",
-    url: "https://github.com/CSSLint/csslint/wiki/Require-all-gradient-definitions",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            gradients;
-
-        parser.addListener("startrule", function() {
-            gradients = {
-                moz: 0,
-                webkit: 0,
-                oldWebkit: 0,
-                o: 0
-            };
-        });
-
-        parser.addListener("property", function(event) {
-
-            if (/\-(moz|o|webkit)(?:\-(?:linear|radial))\-gradient/i.test(event.value)) {
-                gradients[RegExp.$1] = 1;
-            } else if (/\-webkit\-gradient/i.test(event.value)) {
-                gradients.oldWebkit = 1;
-            }
-
-        });
-
-        parser.addListener("endrule", function(event) {
-            var missing = [];
-
-            if (!gradients.moz) {
-                missing.push("Firefox 3.6+");
-            }
-
-            if (!gradients.webkit) {
-                missing.push("Webkit (Safari 5+, Chrome)");
-            }
-
-            if (!gradients.oldWebkit) {
-                missing.push("Old Webkit (Safari 4+, Chrome)");
-            }
-
-            if (!gradients.o) {
-                missing.push("Opera 11.1+");
-            }
-
-            if (missing.length && missing.length < 4) {
-                reporter.report("Missing vendor-prefixed CSS gradients for " + missing.join(", ") + ".", event.selectors[0].line, event.selectors[0].col, rule);
-            }
-
-        });
-
-    }
-
-});
-
-/*
- * Rule: Don't use IDs for selectors.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "ids",
-    name: "Disallow IDs in selectors",
-    desc: "Selectors should not contain IDs.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-IDs-in-selectors",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-        parser.addListener("startrule", function(event) {
-            var selectors = event.selectors,
-                selector,
-                part,
-                modifier,
-                idCount,
-                i, j, k;
-
-            for (i=0; i < selectors.length; i++) {
-                selector = selectors[i];
-                idCount = 0;
-
-                for (j=0; j < selector.parts.length; j++) {
-                    part = selector.parts[j];
-                    if (part.type === parser.SELECTOR_PART_TYPE) {
-                        for (k=0; k < part.modifiers.length; k++) {
-                            modifier = part.modifiers[k];
-                            if (modifier.type === "id") {
-                                idCount++;
-                            }
-                        }
-                    }
-                }
-
-                if (idCount === 1) {
-                    reporter.report("Don't use IDs in selectors.", selector.line, selector.col, rule);
-                } else if (idCount > 1) {
-                    reporter.report(idCount + " IDs in the selector, really?", selector.line, selector.col, rule);
-                }
-            }
-
-        });
-    }
-
-});
-
-/*
- * Rule: IE6-9 supports up to 31 stylesheet import.
- * Reference:
- * http://blogs.msdn.com/b/ieinternals/archive/2011/05/14/internet-explorer-stylesheet-rule-selector-import-sheet-limit-maximum.aspx
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "import-ie-limit",
-    name: "@import limit on IE6-IE9",
-    desc: "IE6-9 supports up to 31 @import per stylesheet",
-    browsers: "IE6, IE7, IE8, IE9",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            MAX_IMPORT_COUNT = 31,
-            count = 0;
-
-        function startPage() {
-            count = 0;
-        }
-
-        parser.addListener("startpage", startPage);
-
-        parser.addListener("import", function() {
-            count++;
-        });
-
-        parser.addListener("endstylesheet", function() {
-            if (count > MAX_IMPORT_COUNT) {
-                reporter.rollupError(
-                    "Too many @import rules (" + count + "). IE6-9 supports up to 31 import per stylesheet.",
-                    rule
-                );
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Don't use @import, use <link> instead.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "import",
-    name: "Disallow @import",
-    desc: "Don't use @import, use <link> instead.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-%40import",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        parser.addListener("import", function(event) {
-            reporter.report("@import prevents parallel downloads, use <link> instead.", event.line, event.col, rule);
-        });
-
-    }
-
-});
-
-/*
- * Rule: Make sure !important is not overused, this could lead to specificity
- * war. Display a warning on !important declarations, an error if it's
- * used more at least 10 times.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "important",
-    name: "Disallow !important",
-    desc: "Be careful when using !important declaration",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-%21important",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            count = 0;
-
-        // warn that important is used and increment the declaration counter
-        parser.addListener("property", function(event) {
-            if (event.important === true) {
-                count++;
-                reporter.report("Use of !important", event.line, event.col, rule);
-            }
-        });
-
-        // if there are more than 10, show an error
-        parser.addListener("endstylesheet", function() {
-            reporter.stat("important", count);
-            if (count >= 10) {
-                reporter.rollupWarn("Too many !important declarations (" + count + "), try to use less than 10 to avoid specificity issues.", rule);
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Properties should be known (listed in CSS3 specification) or
- * be a vendor-prefixed property.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "known-properties",
-    name: "Require use of known properties",
-    desc: "Properties should be known (listed in CSS3 specification) or be a vendor-prefixed property.",
-    url: "https://github.com/CSSLint/csslint/wiki/Require-use-of-known-properties",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        parser.addListener("property", function(event) {
-
-            // the check is handled entirely by the parser-lib (https://github.com/nzakas/parser-lib)
-            if (event.invalid) {
-                reporter.report(event.invalid.message, event.line, event.col, rule);
-            }
-
-        });
-    }
-
-});
-
-/*
- * Rule: All properties should be in alphabetical order.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "order-alphabetical",
-    name: "Alphabetical order",
-    desc: "Assure properties are in alphabetical order",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            properties;
-
-        var startRule = function () {
-            properties = [];
-        };
-
-        var endRule = function(event) {
-            var currentProperties = properties.join(","),
-                expectedProperties = properties.sort().join(",");
-
-            if (currentProperties !== expectedProperties) {
-                reporter.report("Rule doesn't have all its properties in alphabetical order.", event.line, event.col, rule);
-            }
-        };
-
-        parser.addListener("startrule", startRule);
-        parser.addListener("startfontface", startRule);
-        parser.addListener("startpage", startRule);
-        parser.addListener("startpagemargin", startRule);
-        parser.addListener("startkeyframerule", startRule);
-        parser.addListener("startviewport", startRule);
-
-        parser.addListener("property", function(event) {
-            var name = event.property.text,
-                lowerCasePrefixLessName = name.toLowerCase().replace(/^-.*?-/, "");
-
-            properties.push(lowerCasePrefixLessName);
-        });
-
-        parser.addListener("endrule", endRule);
-        parser.addListener("endfontface", endRule);
-        parser.addListener("endpage", endRule);
-        parser.addListener("endpagemargin", endRule);
-        parser.addListener("endkeyframerule", endRule);
-        parser.addListener("endviewport", endRule);
-    }
-
-});
-
-/*
- * Rule: outline: none or outline: 0 should only be used in a :focus rule
- *       and only if there are other properties in the same rule.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "outline-none",
-    name: "Disallow outline: none",
-    desc: "Use of outline: none or outline: 0 should be limited to :focus rules.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-outline%3Anone",
-    browsers: "All",
-    tags: ["Accessibility"],
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            lastRule;
-
-        function startRule(event) {
-            if (event.selectors) {
-                lastRule = {
-                    line: event.line,
-                    col: event.col,
-                    selectors: event.selectors,
-                    propCount: 0,
-                    outline: false
-                };
-            } else {
-                lastRule = null;
-            }
-        }
-
-        function endRule() {
-            if (lastRule) {
-                if (lastRule.outline) {
-                    if (lastRule.selectors.toString().toLowerCase().indexOf(":focus") === -1) {
-                        reporter.report("Outlines should only be modified using :focus.", lastRule.line, lastRule.col, rule);
-                    } else if (lastRule.propCount === 1) {
-                        reporter.report("Outlines shouldn't be hidden unless other visual changes are made.", lastRule.line, lastRule.col, rule);
-                    }
-                }
-            }
-        }
-
-        parser.addListener("startrule", startRule);
-        parser.addListener("startfontface", startRule);
-        parser.addListener("startpage", startRule);
-        parser.addListener("startpagemargin", startRule);
-        parser.addListener("startkeyframerule", startRule);
-        parser.addListener("startviewport", startRule);
-
-        parser.addListener("property", function(event) {
-            var name = event.property.text.toLowerCase(),
-                value = event.value;
-
-            if (lastRule) {
-                lastRule.propCount++;
-                if (name === "outline" && (value.toString() === "none" || value.toString() === "0")) {
-                    lastRule.outline = true;
-                }
-            }
-
-        });
-
-        parser.addListener("endrule", endRule);
-        parser.addListener("endfontface", endRule);
-        parser.addListener("endpage", endRule);
-        parser.addListener("endpagemargin", endRule);
-        parser.addListener("endkeyframerule", endRule);
-        parser.addListener("endviewport", endRule);
-
-    }
-
-});
-
-/*
- * Rule: Don't use classes or IDs with elements (a.foo or a#foo).
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "overqualified-elements",
-    name: "Disallow overqualified elements",
-    desc: "Don't use classes or IDs with elements (a.foo or a#foo).",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-overqualified-elements",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            classes = {};
-
-        parser.addListener("startrule", function(event) {
-            var selectors = event.selectors,
-                selector,
-                part,
-                modifier,
-                i, j, k;
-
-            for (i=0; i < selectors.length; i++) {
-                selector = selectors[i];
-
-                for (j=0; j < selector.parts.length; j++) {
-                    part = selector.parts[j];
-                    if (part.type === parser.SELECTOR_PART_TYPE) {
-                        for (k=0; k < part.modifiers.length; k++) {
-                            modifier = part.modifiers[k];
-                            if (part.elementName && modifier.type === "id") {
-                                reporter.report("Element (" + part + ") is overqualified, just use " + modifier + " without element name.", part.line, part.col, rule);
-                            } else if (modifier.type === "class") {
-
-                                if (!classes[modifier]) {
-                                    classes[modifier] = [];
-                                }
-                                classes[modifier].push({
-                                    modifier: modifier,
-                                    part: part
-                                });
-                            }
-                        }
-                    }
-                }
-            }
-        });
-
-        parser.addListener("endstylesheet", function() {
-
-            var prop;
-            for (prop in classes) {
-                if (classes.hasOwnProperty(prop)) {
-
-                    // one use means that this is overqualified
-                    if (classes[prop].length === 1 && classes[prop][0].part.elementName) {
-                        reporter.report("Element (" + classes[prop][0].part + ") is overqualified, just use " + classes[prop][0].modifier + " without element name.", classes[prop][0].part.line, classes[prop][0].part.col, rule);
-                    }
-                }
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Headings (h1-h6) should not be qualified (namespaced).
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "qualified-headings",
-    name: "Disallow qualified headings",
-    desc: "Headings should not be qualified (namespaced).",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-qualified-headings",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        parser.addListener("startrule", function(event) {
-            var selectors = event.selectors,
-                selector,
-                part,
-                i, j;
-
-            for (i=0; i < selectors.length; i++) {
-                selector = selectors[i];
-
-                for (j=0; j < selector.parts.length; j++) {
-                    part = selector.parts[j];
-                    if (part.type === parser.SELECTOR_PART_TYPE) {
-                        if (part.elementName && /h[1-6]/.test(part.elementName.toString()) && j > 0) {
-                            reporter.report("Heading (" + part.elementName + ") should not be qualified.", part.line, part.col, rule);
-                        }
-                    }
-                }
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Selectors that look like regular expressions are slow and should be avoided.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "regex-selectors",
-    name: "Disallow selectors that look like regexs",
-    desc: "Selectors that look like regular expressions are slow and should be avoided.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-selectors-that-look-like-regular-expressions",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        parser.addListener("startrule", function(event) {
-            var selectors = event.selectors,
-                selector,
-                part,
-                modifier,
-                i, j, k;
-
-            for (i=0; i < selectors.length; i++) {
-                selector = selectors[i];
-                for (j=0; j < selector.parts.length; j++) {
-                    part = selector.parts[j];
-                    if (part.type === parser.SELECTOR_PART_TYPE) {
-                        for (k=0; k < part.modifiers.length; k++) {
-                            modifier = part.modifiers[k];
-                            if (modifier.type === "attribute") {
-                                if (/([~\|\^\$\*]=)/.test(modifier)) {
-                                    reporter.report("Attribute selectors with " + RegExp.$1 + " are slow!", modifier.line, modifier.col, rule);
-                                }
-                            }
-
-                        }
-                    }
-                }
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Total number of rules should not exceed x.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "rules-count",
-    name: "Rules Count",
-    desc: "Track how many rules there are.",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var count = 0;
-
-        // count each rule
-        parser.addListener("startrule", function() {
-            count++;
-        });
-
-        parser.addListener("endstylesheet", function() {
-            reporter.stat("rule-count", count);
-        });
-    }
-
-});
-
-/*
- * Rule: Warn people with approaching the IE 4095 limit
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "selector-max-approaching",
-    name: "Warn when approaching the 4095 selector limit for IE",
-    desc: "Will warn when selector count is >= 3800 selectors.",
-    browsers: "IE",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this, count = 0;
-
-        parser.addListener("startrule", function(event) {
-            count += event.selectors.length;
-        });
-
-        parser.addListener("endstylesheet", function() {
-            if (count >= 3800) {
-                reporter.report("You have " + count + " selectors. Internet Explorer supports a maximum of 4095 selectors per stylesheet. Consider refactoring.", 0, 0, rule);
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Warn people past the IE 4095 limit
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "selector-max",
-    name: "Error when past the 4095 selector limit for IE",
-    desc: "Will error when selector count is > 4095.",
-    browsers: "IE",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this, count = 0;
-
-        parser.addListener("startrule", function(event) {
-            count += event.selectors.length;
-        });
-
-        parser.addListener("endstylesheet", function() {
-            if (count > 4095) {
-                reporter.report("You have " + count + " selectors. Internet Explorer supports a maximum of 4095 selectors per stylesheet. Consider refactoring.", 0, 0, rule);
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Avoid new-line characters in selectors.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "selector-newline",
-    name: "Disallow new-line characters in selectors",
-    desc: "New-line characters in selectors are usually a forgotten comma and not a descendant combinator.",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        function startRule(event) {
-            var i, len, selector, p, n, pLen, part, part2, type, currentLine, nextLine,
-                selectors = event.selectors;
-
-            for (i = 0, len = selectors.length; i < len; i++) {
-                selector = selectors[i];
-                for (p = 0, pLen = selector.parts.length; p < pLen; p++) {
-                    for (n = p + 1; n < pLen; n++) {
-                        part = selector.parts[p];
-                        part2 = selector.parts[n];
-                        type = part.type;
-                        currentLine = part.line;
-                        nextLine = part2.line;
-
-                        if (type === "descendant" && nextLine > currentLine) {
-                            reporter.report("newline character found in selector (forgot a comma?)", currentLine, selectors[i].parts[0].col, rule);
-                        }
-                    }
-                }
-
-            }
-        }
-
-        parser.addListener("startrule", startRule);
-
-    }
-});
-
-/*
- * Rule: Use shorthand properties where possible.
- *
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "shorthand",
-    name: "Require shorthand properties",
-    desc: "Use shorthand properties where possible.",
-    url: "https://github.com/CSSLint/csslint/wiki/Require-shorthand-properties",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            prop, i, len,
-            propertiesToCheck = {},
-            properties,
-            mapping = {
-                "margin": [
-                    "margin-top",
-                    "margin-bottom",
-                    "margin-left",
-                    "margin-right"
-                ],
-                "padding": [
-                    "padding-top",
-                    "padding-bottom",
-                    "padding-left",
-                    "padding-right"
-                ]
-            };
-
-        // initialize propertiesToCheck
-        for (prop in mapping) {
-            if (mapping.hasOwnProperty(prop)) {
-                for (i=0, len=mapping[prop].length; i < len; i++) {
-                    propertiesToCheck[mapping[prop][i]] = prop;
-                }
-            }
-        }
-
-        function startRule() {
-            properties = {};
-        }
-
-        // event handler for end of rules
-        function endRule(event) {
-
-            var prop, i, len, total;
-
-            // check which properties this rule has
-            for (prop in mapping) {
-                if (mapping.hasOwnProperty(prop)) {
-                    total=0;
-
-                    for (i=0, len=mapping[prop].length; i < len; i++) {
-                        total += properties[mapping[prop][i]] ? 1 : 0;
-                    }
-
-                    if (total === mapping[prop].length) {
-                        reporter.report("The properties " + mapping[prop].join(", ") + " can be replaced by " + prop + ".", event.line, event.col, rule);
-                    }
-                }
-            }
-        }
-
-        parser.addListener("startrule", startRule);
-        parser.addListener("startfontface", startRule);
-
-        // check for use of "font-size"
-        parser.addListener("property", function(event) {
-            var name = event.property.toString().toLowerCase();
-
-            if (propertiesToCheck[name]) {
-                properties[name] = 1;
-            }
-        });
-
-        parser.addListener("endrule", endRule);
-        parser.addListener("endfontface", endRule);
-
-    }
-
-});
-
-/*
- * Rule: Don't use properties with a star prefix.
- *
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "star-property-hack",
-    name: "Disallow properties with a star prefix",
-    desc: "Checks for the star property hack (targets IE6/7)",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-star-hack",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        // check if property name starts with "*"
-        parser.addListener("property", function(event) {
-            var property = event.property;
-
-            if (property.hack === "*") {
-                reporter.report("Property with star prefix found.", event.property.line, event.property.col, rule);
-            }
-        });
-    }
-});
-
-/*
- * Rule: Don't use text-indent for image replacement if you need to support rtl.
- *
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "text-indent",
-    name: "Disallow negative text-indent",
-    desc: "Checks for text indent less than -99px",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-negative-text-indent",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            textIndent,
-            direction;
-
-
-        function startRule() {
-            textIndent = false;
-            direction = "inherit";
-        }
-
-        // event handler for end of rules
-        function endRule() {
-            if (textIndent && direction !== "ltr") {
-                reporter.report("Negative text-indent doesn't work well with RTL. If you use text-indent for image replacement explicitly set direction for that item to ltr.", textIndent.line, textIndent.col, rule);
-            }
-        }
-
-        parser.addListener("startrule", startRule);
-        parser.addListener("startfontface", startRule);
-
-        // check for use of "font-size"
-        parser.addListener("property", function(event) {
-            var name = event.property.toString().toLowerCase(),
-                value = event.value;
-
-            if (name === "text-indent" && value.parts[0].value < -99) {
-                textIndent = event.property;
-            } else if (name === "direction" && value.toString() === "ltr") {
-                direction = "ltr";
-            }
-        });
-
-        parser.addListener("endrule", endRule);
-        parser.addListener("endfontface", endRule);
-
-    }
-
-});
-
-/*
- * Rule: Don't use properties with a underscore prefix.
- *
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "underscore-property-hack",
-    name: "Disallow properties with an underscore prefix",
-    desc: "Checks for the underscore property hack (targets IE6)",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-underscore-hack",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        // check if property name starts with "_"
-        parser.addListener("property", function(event) {
-            var property = event.property;
-
-            if (property.hack === "_") {
-                reporter.report("Property with underscore prefix found.", event.property.line, event.property.col, rule);
-            }
-        });
-    }
-});
-
-/*
- * Rule: Headings (h1-h6) should be defined only once.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "unique-headings",
-    name: "Headings should only be defined once",
-    desc: "Headings should be defined only once.",
-    url: "https://github.com/CSSLint/csslint/wiki/Headings-should-only-be-defined-once",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        var headings = {
-            h1: 0,
-            h2: 0,
-            h3: 0,
-            h4: 0,
-            h5: 0,
-            h6: 0
-        };
-
-        parser.addListener("startrule", function(event) {
-            var selectors = event.selectors,
-                selector,
-                part,
-                pseudo,
-                i, j;
-
-            for (i=0; i < selectors.length; i++) {
-                selector = selectors[i];
-                part = selector.parts[selector.parts.length-1];
-
-                if (part.elementName && /(h[1-6])/i.test(part.elementName.toString())) {
-
-                    for (j=0; j < part.modifiers.length; j++) {
-                        if (part.modifiers[j].type === "pseudo") {
-                            pseudo = true;
-                            break;
-                        }
-                    }
-
-                    if (!pseudo) {
-                        headings[RegExp.$1]++;
-                        if (headings[RegExp.$1] > 1) {
-                            reporter.report("Heading (" + part.elementName + ") has already been defined.", part.line, part.col, rule);
-                        }
-                    }
-                }
-            }
-        });
-
-        parser.addListener("endstylesheet", function() {
-            var prop,
-                messages = [];
-
-            for (prop in headings) {
-                if (headings.hasOwnProperty(prop)) {
-                    if (headings[prop] > 1) {
-                        messages.push(headings[prop] + " " + prop + "s");
-                    }
-                }
-            }
-
-            if (messages.length) {
-                reporter.rollupWarn("You have " + messages.join(", ") + " defined in this stylesheet.", rule);
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Don't use universal selector because it's slow.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "universal-selector",
-    name: "Disallow universal selector",
-    desc: "The universal selector (*) is known to be slow.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-universal-selector",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        parser.addListener("startrule", function(event) {
-            var selectors = event.selectors,
-                selector,
-                part,
-                i;
-
-            for (i=0; i < selectors.length; i++) {
-                selector = selectors[i];
-
-                part = selector.parts[selector.parts.length-1];
-                if (part.elementName === "*") {
-                    reporter.report(rule.desc, part.line, part.col, rule);
-                }
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: Don't use unqualified attribute selectors because they're just like universal selectors.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "unqualified-attributes",
-    name: "Disallow unqualified attribute selectors",
-    desc: "Unqualified attribute selectors are known to be slow.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-unqualified-attribute-selectors",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-
-        var rule = this;
-
-        parser.addListener("startrule", function(event) {
-
-            var selectors = event.selectors,
-                selectorContainsClassOrId = false,
-                selector,
-                part,
-                modifier,
-                i, k;
-
-            for (i=0; i < selectors.length; i++) {
-                selector = selectors[i];
-
-                part = selector.parts[selector.parts.length-1];
-                if (part.type === parser.SELECTOR_PART_TYPE) {
-                    for (k=0; k < part.modifiers.length; k++) {
-                        modifier = part.modifiers[k];
-
-                        if (modifier.type === "class" || modifier.type === "id") {
-                            selectorContainsClassOrId = true;
-                            break;
-                        }
-                    }
-
-                    if (!selectorContainsClassOrId) {
-                        for (k=0; k < part.modifiers.length; k++) {
-                            modifier = part.modifiers[k];
-                            if (modifier.type === "attribute" && (!part.elementName || part.elementName === "*")) {
-                                reporter.report(rule.desc, part.line, part.col, rule);
-                            }
-                        }
-                    }
-                }
-
-            }
-        });
-    }
-
-});
-
-/*
- * Rule: When using a vendor-prefixed property, make sure to
- * include the standard one.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "vendor-prefix",
-    name: "Require standard property with vendor prefix",
-    desc: "When using a vendor-prefixed property, make sure to include the standard one.",
-    url: "https://github.com/CSSLint/csslint/wiki/Require-standard-property-with-vendor-prefix",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this,
-            properties,
-            num,
-            propertiesToCheck = {
-                "-webkit-border-radius": "border-radius",
-                "-webkit-border-top-left-radius": "border-top-left-radius",
-                "-webkit-border-top-right-radius": "border-top-right-radius",
-                "-webkit-border-bottom-left-radius": "border-bottom-left-radius",
-                "-webkit-border-bottom-right-radius": "border-bottom-right-radius",
-
-                "-o-border-radius": "border-radius",
-                "-o-border-top-left-radius": "border-top-left-radius",
-                "-o-border-top-right-radius": "border-top-right-radius",
-                "-o-border-bottom-left-radius": "border-bottom-left-radius",
-                "-o-border-bottom-right-radius": "border-bottom-right-radius",
-
-                "-moz-border-radius": "border-radius",
-                "-moz-border-radius-topleft": "border-top-left-radius",
-                "-moz-border-radius-topright": "border-top-right-radius",
-                "-moz-border-radius-bottomleft": "border-bottom-left-radius",
-                "-moz-border-radius-bottomright": "border-bottom-right-radius",
-
-                "-moz-column-count": "column-count",
-                "-webkit-column-count": "column-count",
-
-                "-moz-column-gap": "column-gap",
-                "-webkit-column-gap": "column-gap",
-
-                "-moz-column-rule": "column-rule",
-                "-webkit-column-rule": "column-rule",
-
-                "-moz-column-rule-style": "column-rule-style",
-                "-webkit-column-rule-style": "column-rule-style",
-
-                "-moz-column-rule-color": "column-rule-color",
-                "-webkit-column-rule-color": "column-rule-color",
-
-                "-moz-column-rule-width": "column-rule-width",
-                "-webkit-column-rule-width": "column-rule-width",
-
-                "-moz-column-width": "column-width",
-                "-webkit-column-width": "column-width",
-
-                "-webkit-column-span": "column-span",
-                "-webkit-columns": "columns",
-
-                "-moz-box-shadow": "box-shadow",
-                "-webkit-box-shadow": "box-shadow",
-
-                "-moz-transform": "transform",
-                "-webkit-transform": "transform",
-                "-o-transform": "transform",
-                "-ms-transform": "transform",
-
-                "-moz-transform-origin": "transform-origin",
-                "-webkit-transform-origin": "transform-origin",
-                "-o-transform-origin": "transform-origin",
-                "-ms-transform-origin": "transform-origin",
-
-                "-moz-box-sizing": "box-sizing",
-                "-webkit-box-sizing": "box-sizing"
-            };
-
-        // event handler for beginning of rules
-        function startRule() {
-            properties = {};
-            num = 1;
-        }
-
-        // event handler for end of rules
-        function endRule() {
-            var prop,
-                i,
-                len,
-                needed,
-                actual,
-                needsStandard = [];
-
-            for (prop in properties) {
-                if (propertiesToCheck[prop]) {
-                    needsStandard.push({
-                        actual: prop,
-                        needed: propertiesToCheck[prop]
-                    });
-                }
-            }
-
-            for (i=0, len=needsStandard.length; i < len; i++) {
-                needed = needsStandard[i].needed;
-                actual = needsStandard[i].actual;
-
-                if (!properties[needed]) {
-                    reporter.report("Missing standard property '" + needed + "' to go along with '" + actual + "'.", properties[actual][0].name.line, properties[actual][0].name.col, rule);
-                } else {
-                    // make sure standard property is last
-                    if (properties[needed][0].pos < properties[actual][0].pos) {
-                        reporter.report("Standard property '" + needed + "' should come after vendor-prefixed property '" + actual + "'.", properties[actual][0].name.line, properties[actual][0].name.col, rule);
-                    }
-                }
-            }
-
-        }
-
-        parser.addListener("startrule", startRule);
-        parser.addListener("startfontface", startRule);
-        parser.addListener("startpage", startRule);
-        parser.addListener("startpagemargin", startRule);
-        parser.addListener("startkeyframerule", startRule);
-        parser.addListener("startviewport", startRule);
-
-        parser.addListener("property", function(event) {
-            var name = event.property.text.toLowerCase();
-
-            if (!properties[name]) {
-                properties[name] = [];
-            }
-
-            properties[name].push({
-                name: event.property,
-                value: event.value,
-                pos: num++
-            });
-        });
-
-        parser.addListener("endrule", endRule);
-        parser.addListener("endfontface", endRule);
-        parser.addListener("endpage", endRule);
-        parser.addListener("endpagemargin", endRule);
-        parser.addListener("endkeyframerule", endRule);
-        parser.addListener("endviewport", endRule);
-    }
-
-});
-
-/*
- * Rule: You don't need to specify units when a value is 0.
- */
-
-CSSLint.addRule({
-
-    // rule information
-    id: "zero-units",
-    name: "Disallow units for 0 values",
-    desc: "You don't need to specify units when a value is 0.",
-    url: "https://github.com/CSSLint/csslint/wiki/Disallow-units-for-zero-values",
-    browsers: "All",
-
-    // initialization
-    init: function(parser, reporter) {
-        "use strict";
-        var rule = this;
-
-        // count how many times "float" is used
-        parser.addListener("property", function(event) {
-            var parts = event.value.parts,
-                i = 0,
-                len = parts.length;
-
-            while (i < len) {
-                if ((parts[i].units || parts[i].type === "percentage") && parts[i].value === 0 && parts[i].type !== "time") {
-                    reporter.report("Values of 0 shouldn't have units specified.", parts[i].line, parts[i].col, rule);
-                }
-                i++;
-            }
-
-        });
-
-    }
-
-});
-
-(function() {
-    "use strict";
-
-    /**
-     * Replace special characters before write to output.
-     *
-     * Rules:
-     *  - single quotes is the escape sequence for double-quotes
-     *  - &amp; is the escape sequence for &
-     *  - &lt; is the escape sequence for <
-     *  - &gt; is the escape sequence for >
-     *
-     * @param {String} message to escape
-     * @return escaped message as {String}
-     */
-    var xmlEscape = function(str) {
-        if (!str || str.constructor !== String) {
-            return "";
-        }
-
-        return str.replace(/["&><]/g, function(match) {
-            switch (match) {
-                case "\"":
-                    return "&quot;";
-                case "&":
-                    return "&amp;";
-                case "<":
-                    return "&lt;";
-                case ">":
-                    return "&gt;";
-            }
-        });
-    };
-
-    CSSLint.addFormatter({
-        // format information
-        id: "checkstyle-xml",
-        name: "Checkstyle XML format",
-
-        /**
-         * Return opening root XML tag.
-         * @return {String} to prepend before all results
-         */
-        startFormat: function() {
-            return "<?xml version=\"1.0\" encoding=\"utf-8\"?><checkstyle>";
-        },
-
-        /**
-         * Return closing root XML tag.
-         * @return {String} to append after all results
-         */
-        endFormat: function() {
-            return "</checkstyle>";
-        },
-
-        /**
-         * Returns message when there is a file read error.
-         * @param {String} filename The name of the file that caused the error.
-         * @param {String} message The error message
-         * @return {String} The error message.
-         */
-        readError: function(filename, message) {
-            return "<file name=\"" + xmlEscape(filename) + "\"><error line=\"0\" column=\"0\" severty=\"error\" message=\"" + xmlEscape(message) + "\"></error></file>";
-        },
-
-        /**
-         * Given CSS Lint results for a file, return output for this format.
-         * @param results {Object} with error and warning messages
-         * @param filename {String} relative file path
-         * @param options {Object} (UNUSED for now) specifies special handling of output
-         * @return {String} output for results
-         */
-        formatResults: function(results, filename/*, options*/) {
-            var messages = results.messages,
-                output = [];
-
-            /**
-             * Generate a source string for a rule.
-             * Checkstyle source strings usually resemble Java class names e.g
-             * net.csslint.SomeRuleName
-             * @param {Object} rule
-             * @return rule source as {String}
-             */
-            var generateSource = function(rule) {
-                if (!rule || !("name" in rule)) {
-                    return "";
-                }
-                return "net.csslint." + rule.name.replace(/\s/g, "");
-            };
-
-
-            if (messages.length > 0) {
-                output.push("<file name=\""+filename+"\">");
-                CSSLint.Util.forEach(messages, function (message) {
-                    // ignore rollups for now
-                    if (!message.rollup) {
-                        output.push("<error line=\"" + message.line + "\" column=\"" + message.col + "\" severity=\"" + message.type + "\"" +
-                          " message=\"" + xmlEscape(message.message) + "\" source=\"" + generateSource(message.rule) +"\"/>");
-                    }
-                });
-                output.push("</file>");
-            }
-
-            return output.join("");
-        }
-    });
-
-}());
-
-CSSLint.addFormatter({
-    // format information
-    id: "compact",
-    name: "Compact, 'porcelain' format",
-
-    /**
-     * Return content to be printed before all file results.
-     * @return {String} to prepend before all results
-     */
-    startFormat: function() {
-        "use strict";
-        return "";
-    },
-
-    /**
-     * Return content to be printed after all file results.
-     * @return {String} to append after all results
-     */
-    endFormat: function() {
-        "use strict";
-        return "";
-    },
-
-    /**
-     * Given CSS Lint results for a file, return output for this format.
-     * @param results {Object} with error and warning messages
-     * @param filename {String} relative file path
-     * @param options {Object} (Optional) specifies special handling of output
-     * @return {String} output for results
-     */
-    formatResults: function(results, filename, options) {
-        "use strict";
-        var messages = results.messages,
-            output = "";
-        options = options || {};
-
-        /**
-         * Capitalize and return given string.
-         * @param str {String} to capitalize
-         * @return {String} capitalized
-         */
-        var capitalize = function(str) {
-            return str.charAt(0).toUpperCase() + str.slice(1);
-        };
-
-        if (messages.length === 0) {
-            return options.quiet ? "" : filename + ": Lint Free!";
-        }
-
-        CSSLint.Util.forEach(messages, function(message) {
-            if (message.rollup) {
-                output += filename + ": " + capitalize(message.type) + " - " + message.message + " (" + message.rule.id + ")\n";
-            } else {
-                output += filename + ": line " + message.line +
-                    ", col " + message.col + ", " + capitalize(message.type) + " - " + message.message + " (" + message.rule.id + ")\n";
-            }
-        });
-
-        return output;
-    }
-});
-
-CSSLint.addFormatter({
-    // format information
-    id: "csslint-xml",
-    name: "CSSLint XML format",
-
-    /**
-     * Return opening root XML tag.
-     * @return {String} to prepend before all results
-     */
-    startFormat: function() {
-        "use strict";
-        return "<?xml version=\"1.0\" encoding=\"utf-8\"?><csslint>";
-    },
-
-    /**
-     * Return closing root XML tag.
-     * @return {String} to append after all results
-     */
-    endFormat: function() {
-        "use strict";
-        return "</csslint>";
-    },
-
-    /**
-     * Given CSS Lint results for a file, return output for this format.
-     * @param results {Object} with error and warning messages
-     * @param filename {String} relative file path
-     * @param options {Object} (UNUSED for now) specifies special handling of output
-     * @return {String} output for results
-     */
-    formatResults: function(results, filename/*, options*/) {
-        "use strict";
-        var messages = results.messages,
-            output = [];
-
-        /**
-         * Replace special characters before write to output.
-         *
-         * Rules:
-         *  - single quotes is the escape sequence for double-quotes
-         *  - &amp; is the escape sequence for &
-         *  - &lt; is the escape sequence for <
-         *  - &gt; is the escape sequence for >
-         *
-         * @param {String} message to escape
-         * @return escaped message as {String}
-         */
-        var escapeSpecialCharacters = function(str) {
-            if (!str || str.constructor !== String) {
-                return "";
-            }
-            return str.replace(/"/g, "'").replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
-        };
-
-        if (messages.length > 0) {
-            output.push("<file name=\""+filename+"\">");
-            CSSLint.Util.forEach(messages, function (message) {
-                if (message.rollup) {
-                    output.push("<issue severity=\"" + message.type + "\" reason=\"" + escapeSpecialCharacters(message.message) + "\" evidence=\"" + escapeSpecialCharacters(message.evidence) + "\"/>");
-                } else {
-                    output.push("<issue line=\"" + message.line + "\" char=\"" + message.col + "\" severity=\"" + message.type + "\"" +
-                        " reason=\"" + escapeSpecialCharacters(message.message) + "\" evidence=\"" + escapeSpecialCharacters(message.evidence) + "\"/>");
-                }
-            });
-            output.push("</file>");
-        }
-
-        return output.join("");
-    }
-});
-
-/* globals JSON: true */
-
-CSSLint.addFormatter({
-    // format information
-    id: "json",
-    name: "JSON",
-
-    /**
-     * Return content to be printed before all file results.
-     * @return {String} to prepend before all results
-     */
-    startFormat: function() {
-        "use strict";
-        this.json = [];
-        return "";
-    },
-
-    /**
-     * Return content to be printed after all file results.
-     * @return {String} to append after all results
-     */
-    endFormat: function() {
-        "use strict";
-        var ret = "";
-        if (this.json.length > 0) {
-            if (this.json.length === 1) {
-                ret = JSON.stringify(this.json[0]);
-            } else {
-                ret = JSON.stringify(this.json);
-            }
-        }
-        return ret;
-    },
-
-    /**
-     * Given CSS Lint results for a file, return output for this format.
-     * @param results {Object} with error and warning messages
-     * @param filename {String} relative file path (Unused)
-     * @return {String} output for results
-     */
-    formatResults: function(results, filename, options) {
-        "use strict";
-        if (results.messages.length > 0 || !options.quiet) {
-            this.json.push({
-                filename: filename,
-                messages: results.messages,
-                stats: results.stats
-            });
-        }
-        return "";
-    }
-});
-
-CSSLint.addFormatter({
-    // format information
-    id: "junit-xml",
-    name: "JUNIT XML format",
-
-    /**
-     * Return opening root XML tag.
-     * @return {String} to prepend before all results
-     */
-    startFormat: function() {
-        "use strict";
-        return "<?xml version=\"1.0\" encoding=\"utf-8\"?><testsuites>";
-    },
-
-    /**
-     * Return closing root XML tag.
-     * @return {String} to append after all results
-     */
-    endFormat: function() {
-        "use strict";
-        return "</testsuites>";
-    },
-
-    /**
-     * Given CSS Lint results for a file, return output for this format.
-     * @param results {Object} with error and warning messages
-     * @param filename {String} relative file path
-     * @param options {Object} (UNUSED for now) specifies special handling of output
-     * @return {String} output for results
-     */
-    formatResults: function(results, filename/*, options*/) {
-        "use strict";
-
-        var messages = results.messages,
-            output = [],
-            tests = {
-                "error": 0,
-                "failure": 0
-            };
-
-        /**
-         * Generate a source string for a rule.
-         * JUNIT source strings usually resemble Java class names e.g
-         * net.csslint.SomeRuleName
-         * @param {Object} rule
-         * @return rule source as {String}
-         */
-        var generateSource = function(rule) {
-            if (!rule || !("name" in rule)) {
-                return "";
-            }
-            return "net.csslint." + rule.name.replace(/\s/g, "");
-        };
-
-        /**
-         * Replace special characters before write to output.
-         *
-         * Rules:
-         *  - single quotes is the escape sequence for double-quotes
-         *  - &lt; is the escape sequence for <
-         *  - &gt; is the escape sequence for >
-         *
-         * @param {String} message to escape
-         * @return escaped message as {String}
-         */
-        var escapeSpecialCharacters = function(str) {
-
-            if (!str || str.constructor !== String) {
-                return "";
-            }
-
-            return str.replace(/"/g, "'").replace(/</g, "&lt;").replace(/>/g, "&gt;");
-
-        };
-
-        if (messages.length > 0) {
-
-            messages.forEach(function (message) {
-
-                // since junit has no warning class
-                // all issues as errors
-                var type = message.type === "warning" ? "error" : message.type;
-
-                // ignore rollups for now
-                if (!message.rollup) {
-
-                    // build the test case separately, once joined
-                    // we'll add it to a custom array filtered by type
-                    output.push("<testcase time=\"0\" name=\"" + generateSource(message.rule) + "\">");
-                    output.push("<" + type + " message=\"" + escapeSpecialCharacters(message.message) + "\"><![CDATA[" + message.line + ":" + message.col + ":" + escapeSpecialCharacters(message.evidence) + "]]></" + type + ">");
-                    output.push("</testcase>");
-
-                    tests[type] += 1;
-
-                }
-
-            });
-
-            output.unshift("<testsuite time=\"0\" tests=\"" + messages.length + "\" skipped=\"0\" errors=\"" + tests.error + "\" failures=\"" + tests.failure + "\" package=\"net.csslint\" name=\"" + filename + "\">");
-            output.push("</testsuite>");
-
-        }
-
-        return output.join("");
-
-    }
-});
-
-CSSLint.addFormatter({
-    // format information
-    id: "lint-xml",
-    name: "Lint XML format",
-
-    /**
-     * Return opening root XML tag.
-     * @return {String} to prepend before all results
-     */
-    startFormat: function() {
-        "use strict";
-        return "<?xml version=\"1.0\" encoding=\"utf-8\"?><lint>";
-    },
-
-    /**
-     * Return closing root XML tag.
-     * @return {String} to append after all results
-     */
-    endFormat: function() {
-        "use strict";
-        return "</lint>";
-    },
-
-    /**
-     * Given CSS Lint results for a file, return output for this format.
-     * @param results {Object} with error and warning messages
-     * @param filename {String} relative file path
-     * @param options {Object} (UNUSED for now) specifies special handling of output
-     * @return {String} output for results
-     */
-    formatResults: function(results, filename/*, options*/) {
-        "use strict";
-        var messages = results.messages,
-            output = [];
-
-        /**
-         * Replace special characters before write to output.
-         *
-         * Rules:
-         *  - single quotes is the escape sequence for double-quotes
-         *  - &amp; is the escape sequence for &
-         *  - &lt; is the escape sequence for <
-         *  - &gt; is the escape sequence for >
-         *
-         * @param {String} message to escape
-         * @return escaped message as {String}
-         */
-        var escapeSpecialCharacters = function(str) {
-            if (!str || str.constructor !== String) {
-                return "";
-            }
-            return str.replace(/"/g, "'").replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
-        };
-
-        if (messages.length > 0) {
-
-            output.push("<file name=\""+filename+"\">");
-            CSSLint.Util.forEach(messages, function (message) {
-                if (message.rollup) {
-                    output.push("<issue severity=\"" + message.type + "\" reason=\"" + escapeSpecialCharacters(message.message) + "\" evidence=\"" + escapeSpecialCharacters(message.evidence) + "\"/>");
-                } else {
-                    var rule = "";
-                    if (message.rule && message.rule.id) {
-                        rule = "rule=\"" + escapeSpecialCharacters(message.rule.id) + "\" ";
-                    }
-                    output.push("<issue " + rule + "line=\"" + message.line + "\" char=\"" + message.col + "\" severity=\"" + message.type + "\"" +
-                        " reason=\"" + escapeSpecialCharacters(message.message) + "\" evidence=\"" + escapeSpecialCharacters(message.evidence) + "\"/>");
-                }
-            });
-            output.push("</file>");
-        }
-
-        return output.join("");
-    }
-});
-
-CSSLint.addFormatter({
-    // format information
-    id: "text",
-    name: "Plain Text",
-
-    /**
-     * Return content to be printed before all file results.
-     * @return {String} to prepend before all results
-     */
-    startFormat: function() {
-        "use strict";
-        return "";
-    },
-
-    /**
-     * Return content to be printed after all file results.
-     * @return {String} to append after all results
-     */
-    endFormat: function() {
-        "use strict";
-        return "";
-    },
-
-    /**
-     * Given CSS Lint results for a file, return output for this format.
-     * @param results {Object} with error and warning messages
-     * @param filename {String} relative file path
-     * @param options {Object} (Optional) specifies special handling of output
-     * @return {String} output for results
-     */
-    formatResults: function(results, filename, options) {
-        "use strict";
-        var messages = results.messages,
-            output = "";
-        options = options || {};
-
-        if (messages.length === 0) {
-            return options.quiet ? "" : "\n\ncsslint: No errors in " + filename + ".";
-        }
-
-        output = "\n\ncsslint: There ";
-        if (messages.length === 1) {
-            output += "is 1 problem";
-        } else {
-            output += "are " + messages.length + " problems";
-        }
-        output += " in " + filename + ".";
-
-        var pos = filename.lastIndexOf("/"),
-            shortFilename = filename;
-
-        if (pos === -1) {
-            pos = filename.lastIndexOf("\\");
-        }
-        if (pos > -1) {
-            shortFilename = filename.substring(pos+1);
-        }
-
-        CSSLint.Util.forEach(messages, function (message, i) {
-            output = output + "\n\n" + shortFilename;
-            if (message.rollup) {
-                output += "\n" + (i+1) + ": " + message.type;
-                output += "\n" + message.message;
-            } else {
-                output += "\n" + (i+1) + ": " + message.type + " at line " + message.line + ", col " + message.col;
-                output += "\n" + message.message;
-                output += "\n" + message.evidence;
-            }
-        });
-
-        return output;
-    }
-});
-
-parserlib.css.Tokens[parserlib.css.Tokens.COMMENT].hide = false;
-
-self.onmessage = ({data: {action = 'run', code, config}}) => {
-  switch (action) {
-
-    case 'getAllRuleIds':
-      // the functions are non-tranferable and we need only an id
-      self.postMessage(CSSLint.getRules().map(rule => rule.id));
-      return;
-
-    case 'getAllRuleInfos':
-      // the functions are non-tranferable
-      self.postMessage(CSSLint.getRules().map(rule => JSON.parse(JSON.stringify(rule))));
-      return;
-
-    case 'run': {
-      const results = CSSLint.verify(code, config).messages
-        .filter(m => !m.message.includes('/*[[') && !m.message.includes(']]*/'))
-        .map(m => Object.assign(m, {rule: {id: m.rule.id}}));
-      self.postMessage(results);
-      return;
-    }
-    case 'parse':
-      if (!self.mozParser) {
-        self.importScripts('/js/moz-parser.js');
-      }
-      mozParser.parse(code)
-        .then(sections => self.postMessage(sections))
-        .catch(info => self.postMessage({__ERROR__: info}));
-  }
-};
diff --git a/vendor-overwrites/csslint/csslint.js b/vendor-overwrites/csslint/csslint.js
new file mode 100644
index 00000000..cdcbc9c1
--- /dev/null
+++ b/vendor-overwrites/csslint/csslint.js
@@ -0,0 +1,1723 @@
+/*
+Modded by tophf <github.com/tophf>
+========== Original disclaimer:
+
+Copyright (c) 2016 Nicole Sullivan and Nicholas C. Zakas. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the 'Software'), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+/* global parserlib */
+'use strict';
+
+//region Reporter
+
+class Reporter {
+  /**
+   * An instance of Report is used to report results of the
+   * verification back to the main API.
+   * @class Reporter
+   * @constructor
+   * @param {String[]} lines The text lines of the source.
+   * @param {Object} ruleset The set of rules to work with, including if
+   *      they are errors or warnings.
+   * @param {Object} explicitly allowed lines
+   * @param {[][]} ingore list of line ranges to be ignored
+   */
+  constructor(lines, ruleset, allow, ignore) {
+    this.messages = [];
+    this.stats = [];
+    this.lines = lines;
+    this.ruleset = ruleset;
+    this.allow = allow || {};
+    this.ignore = ignore || [];
+  }
+
+  error(message, line, col, rule = {}) {
+    this.messages.push({
+      type:     'error',
+      evidence: this.lines[line - 1],
+      line, col,
+      message,
+      rule,
+    });
+  }
+
+  report(message, line, col, rule) {
+    if (line in this.allow && rule.id in this.allow[line] ||
+        this.ignore.some(range => range[0] <= line && line <= range[1])) {
+      return;
+    }
+    this.messages.push({
+      type:     this.ruleset[rule.id] === 2 ? 'error' : 'warning',
+      evidence: this.lines[line - 1],
+      line, col,
+      message,
+      rule,
+    });
+  }
+
+  info(message, line, col, rule) {
+    this.messages.push({
+      type:     'info',
+      evidence: this.lines[line - 1],
+      line, col,
+      message,
+      rule,
+    });
+  }
+
+  rollupError(message, rule) {
+    this.messages.push({
+      type:   'error',
+      rollup: true,
+      message,
+      rule,
+    });
+  }
+
+  rollupWarn(message, rule) {
+    this.messages.push({
+      type:   'warning',
+      rollup: true,
+      message,
+      rule,
+    });
+  }
+
+  stat(name, value) {
+    this.stats[name] = value;
+  }
+}
+
+//endregion
+//region CSSLint
+
+//eslint-disable-next-line no-var
+var CSSLint = (() => {
+
+  const RX_EMBEDDED = /\/\*\s*csslint\s+((?:[^*]|\*(?!\/))+?)\*\//igu;
+  const EBMEDDED_RULE_VALUE_MAP = {
+    // error
+    'true':  2,
+    '2':     2,
+    // warning
+    '':      1,
+    '1':     1,
+    // ignore
+    'false': 0,
+    '0':     0,
+  };
+  const rules = [];
+
+  return Object.assign(new parserlib.util.EventTarget(), {
+
+    addRule(rule) {
+      rules.push(rule);
+      rules[rule.id] = rule;
+    },
+
+    clearRules() {
+      rules.length = 0;
+    },
+
+    getRules() {
+      return rules
+        .slice()
+        .sort((a, b) =>
+          a.id < b.id ? -1 :
+            a.id > b.id ? 1 : 0);
+    },
+
+    getRuleset() {
+      const ruleset = {};
+      // by default, everything is a warning
+      for (const rule of rules) {
+        ruleset[rule.id] = 1;
+      }
+      return ruleset;
+    },
+
+    /**
+     * Starts the verification process for the given CSS text.
+     * @param {String} text The CSS text to verify.
+     * @param {Object} ruleset (Optional) List of rules to apply. If null, then
+     *      all rules are used. If a rule has a value of 1 then it's a warning,
+     *      a value of 2 means it's an error.
+     * @return {Object} Results of the verification.
+     */
+    verify(text, ruleset) {
+
+      if (!ruleset) ruleset = this.getRuleset();
+
+      const allow = {};
+      const ignore = [];
+      RX_EMBEDDED.lastIndex =
+        text.lastIndexOf('/*',
+          text.indexOf('csslint',
+            text.indexOf('/*') + 1 || text.length) + 1);
+      if (RX_EMBEDDED.lastIndex >= 0) {
+        ruleset = Object.assign({}, ruleset);
+        applyEmbeddedOverrides(text, ruleset, allow, ignore);
+      }
+
+      const parser = new parserlib.css.Parser({
+        starHack:       true,
+        ieFilters:      true,
+        underscoreHack: true,
+        strict:         false,
+      });
+
+      const reporter = new Reporter([], ruleset, allow, ignore);
+
+      // always report parsing errors as errors
+      ruleset.errors = 2;
+      Object.keys(ruleset).forEach(id =>
+        ruleset[id] &&
+        rules[id] &&
+        rules[id].init(parser, reporter));
+
+      try {
+        parser.parse(text, {reuseCache: true});
+      } catch (ex) {
+        reporter.error('Fatal error, cannot continue: ' + ex.message, ex.line, ex.col, {});
+      }
+
+      const report = {
+        messages: reporter.messages,
+        stats:    reporter.stats,
+        ruleset:  reporter.ruleset,
+        allow:    reporter.allow,
+        ignore:   reporter.ignore,
+      };
+
+      // sort by line numbers, rollups at the bottom
+      report.messages.sort((a, b) =>
+        a.rollup && !b.rollup ? 1 :
+        !a.rollup && b.rollup ? -1 :
+        a.line - b.line);
+
+      parserlib.cache.feedback(report);
+
+      return report;
+    },
+  });
+
+  function applyEmbeddedOverrides(text, ruleset, allow, ignore) {
+    let ignoreStart = null;
+    let ignoreEnd = null;
+    let lineno = 0;
+
+    for (let eol = 0, m; (m = RX_EMBEDDED.exec(text)); lineno++) {
+      eol = (text.indexOf('\n', eol) + 1 || text.length + 1) - 1;
+      if (eol < m.index) continue;
+
+      const ovr = m[1].toLowerCase();
+      const cmd = ovr.split(':', 1);
+      const i = cmd.length + 1;
+
+      switch (cmd.trim()) {
+
+        case 'allow': {
+          const allowRuleset = {};
+          let num = 0;
+          ovr.slice(i).split(',').forEach(allowRule => {
+            allowRuleset[allowRule.trim()] = true;
+            num++;
+          });
+          if (num) allow[lineno + 1] = allowRuleset;
+          break;
+        }
+
+        case 'ignore':
+          if (ovr.lastIndexOf('start', i) > 0) {
+            if (ignoreStart === null) {
+              ignoreStart = lineno;
+            }
+            break;
+          }
+          if (ovr.lastIndexOf('end', i) > 0) {
+            ignoreEnd = lineno;
+            if (ignoreStart !== null && ignoreEnd !== null) {
+              ignore.push([ignoreStart, ignoreEnd]);
+              ignoreStart = ignoreEnd = null;
+            }
+          }
+          break;
+
+        default:
+          ovr.slice(i).split(',').forEach(rule => {
+            const pair = rule.split(':');
+            const property = pair[0] || '';
+            const value = pair[1] || '';
+            const mapped = EBMEDDED_RULE_VALUE_MAP[value.trim()];
+            ruleset[property.trim()] = mapped === undefined ? 1 : mapped;
+          });
+      }
+    }
+
+    // Close remaining ignore block, if any
+    if (ignoreStart !== null) {
+      ignore.push([ignoreStart, lineno]);
+    }
+  }
+})();
+
+//endregion
+//region Util
+
+// expose for testing purposes
+CSSLint._Reporter = Reporter;
+
+CSSLint.Util = {
+
+  indexOf(values, value) {
+    if (typeof values.indexOf === 'function') {
+      return values.indexOf(value);
+    }
+    for (let i = 0, len = values.length; i < len; i++) {
+      if (values[i] === value) {
+        return i;
+      }
+    }
+    return -1;
+  },
+
+  registerBlockEvents(parser, start, end, property) {
+    for (const e of [
+      'document',
+      'fontface',
+      'keyframerule',
+      'media',
+      'page',
+      'pagemargin',
+      'rule',
+      'supports',
+      'viewport',
+    ]) {
+      if (start) parser.addListener('start' + e, start);
+      if (end) parser.addListener('end' + e, end);
+    }
+    if (property) parser.addListener('property', property);
+  },
+};
+
+//endregion
+//region Rules
+
+CSSLint.addRule({
+  id:       'adjoining-classes',
+  name:     'Disallow adjoining classes',
+  desc:     "Don't use adjoining classes.",
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-adjoining-classes',
+  browsers: 'IE6',
+
+  init(parser, reporter) {
+    parser.addListener('startrule', event => {
+      for (const selector of event.selectors) {
+        for (const part of selector.parts) {
+          if (part.type !== parser.SELECTOR_PART_TYPE) continue;
+          let classCount = 0;
+          for (const modifier of part.modifiers) {
+            classCount += modifier.type === 'class';
+            if (classCount > 1) {
+              reporter.report('Adjoining classes: ' + selector.text, part.line, part.col, this);
+            }
+          }
+        }
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'box-model',
+  name:     'Beware of broken box size',
+  desc:     "Don't use width or height when using padding or border.",
+  url:      'https://github.com/CSSLint/csslint/wiki/Beware-of-box-model-size',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    const sizeProps = {
+      width:  [
+        'border',
+        'border-left',
+        'border-right',
+        'padding',
+        'padding-left',
+        'padding-right',
+      ],
+      height: [
+        'border',
+        'border-bottom',
+        'border-top',
+        'padding',
+        'padding-bottom',
+        'padding-top',
+      ],
+    };
+    let properties = {};
+    let boxSizing = false;
+    let started = 0;
+
+    const startRule = () => {
+      started = 1;
+      properties = {};
+      boxSizing = false;
+    };
+
+    const property = event => {
+      if (!started) return;
+      const name = event.property.text.toLowerCase();
+
+      if (sizeProps.width.includes(name) || sizeProps.height.includes(name)) {
+
+        if (!/^0+\D*$/.test(event.value) &&
+            (name !== 'border' || !/^none$/i.test(event.value))) {
+          properties[name] = {
+            line:  event.property.line,
+            col:   event.property.col,
+            value: event.value,
+          };
+        }
+
+      } else if (/^(width|height)/i.test(name) &&
+                 /^(length|percentage)/.test(event.value.parts[0].type)) {
+        properties[name] = 1;
+
+      } else if (name === 'box-sizing') {
+        boxSizing = true;
+      }
+    };
+
+    const endRule = () => {
+      started = 0;
+      if (boxSizing) return;
+
+      for (const size in sizeProps) {
+        if (!properties[size]) continue;
+
+        for (const prop of sizeProps[size]) {
+          if (prop !== 'padding' || !properties[prop]) continue;
+
+          const {value: {parts}, line, col} = properties[prop].value;
+          if (parts.length !== 2 || Number(parts[0].value) !== 0) {
+            reporter.report(`Using ${size} with ${prop} can sometimes make elements larger than you expect.`,
+              line, col, this);
+          }
+        }
+      }
+    };
+
+    CSSLint.util.registerBlockEvents(parser, startRule, endRule, property);
+  },
+});
+
+CSSLint.addRule({
+  id:       'box-sizing',
+  name:     'Disallow use of box-sizing',
+  desc:     "The box-sizing properties isn't supported in IE6 and IE7.",
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-box-sizing',
+  browsers: 'IE6, IE7',
+  tags:     ['Compatibility'],
+
+  init(parser, reporter) {
+    parser.addListener('property', event => {
+      if (event.property.text.toLowerCase() === 'box-sizing') {
+        reporter.report(this.desc, event.line, event.col, this);
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'bulletproof-font-face',
+  name:     'Use the bulletproof @font-face syntax',
+  desc:     'Use the bulletproof @font-face syntax to avoid 404\'s in old IE ' +
+            '(http://www.fontspring.com/blog/the-new-bulletproof-font-face-syntax).',
+  url:      'https://github.com/CSSLint/csslint/wiki/Bulletproof-font-face',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    const regex = /^\s?url\(['"].+\.eot\?.*['"]\)\s*format\(['"]embedded-opentype['"]\).*$/i;
+    let firstSrc = true;
+    let ruleFailed = false;
+    let line, col;
+
+    // Mark the start of a @font-face declaration so we only test properties inside it
+    parser.addListener('startfontface', () => {
+      parser.addListener('property', property);
+    });
+
+    function property(event) {
+      const propertyName = event.property.toString().toLowerCase();
+      if (propertyName !== 'src') return;
+
+      const value = event.value.toString();
+      line = event.line;
+      col = event.col;
+
+      const matched = regex.test(value);
+      if (firstSrc && !matched) {
+        ruleFailed = true;
+        firstSrc = false;
+      } else if (!firstSrc && matched) {
+        ruleFailed = false;
+      }
+    }
+
+    // Back to normal rules that we don't need to test
+    parser.addListener('endfontface', () => {
+      parser.removeListener('property', property);
+      if (!ruleFailed) return;
+      reporter.report("@font-face declaration doesn't follow the fontspring bulletproof syntax.",
+        line, col, this);
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'compatible-vendor-prefixes',
+  name:     'Require compatible vendor prefixes',
+  desc:     'Include all compatible vendor prefixes to reach a wider range of users.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Require-compatible-vendor-prefixes',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    // See http://peter.sh/experiments/vendor-prefixed-css-property-overview/ for details
+    const compatiblePrefixes = {
+      'animation':                  'webkit',
+      'animation-delay':            'webkit',
+      'animation-direction':        'webkit',
+      'animation-duration':         'webkit',
+      'animation-fill-mode':        'webkit',
+      'animation-iteration-count':  'webkit',
+      'animation-name':             'webkit',
+      'animation-play-state':       'webkit',
+      'animation-timing-function':  'webkit',
+      'appearance':                 'webkit moz',
+      'border-end':                 'webkit moz',
+      'border-end-color':           'webkit moz',
+      'border-end-style':           'webkit moz',
+      'border-end-width':           'webkit moz',
+      'border-image':               'webkit moz o',
+      'border-radius':              'webkit',
+      'border-start':               'webkit moz',
+      'border-start-color':         'webkit moz',
+      'border-start-style':         'webkit moz',
+      'border-start-width':         'webkit moz',
+      'box-align':                  'webkit moz',
+      'box-direction':              'webkit moz',
+      'box-flex':                   'webkit moz',
+      'box-lines':                  'webkit',
+      'box-ordinal-group':          'webkit moz',
+      'box-orient':                 'webkit moz',
+      'box-pack':                   'webkit moz',
+      'box-sizing':                 '',
+      'box-shadow':                 '',
+      'column-count':               'webkit moz ms',
+      'column-gap':                 'webkit moz ms',
+      'column-rule':                'webkit moz ms',
+      'column-rule-color':          'webkit moz ms',
+      'column-rule-style':          'webkit moz ms',
+      'column-rule-width':          'webkit moz ms',
+      'column-width':               'webkit moz ms',
+      'flex':                       'webkit ms',
+      'flex-basis':                 'webkit',
+      'flex-direction':             'webkit ms',
+      'flex-flow':                  'webkit',
+      'flex-grow':                  'webkit',
+      'flex-shrink':                'webkit',
+      'hyphens':                    'epub moz',
+      'line-break':                 'webkit ms',
+      'margin-end':                 'webkit moz',
+      'margin-start':               'webkit moz',
+      'marquee-speed':              'webkit wap',
+      'marquee-style':              'webkit wap',
+      'padding-end':                'webkit moz',
+      'padding-start':              'webkit moz',
+      'tab-size':                   'moz o',
+      'text-size-adjust':           'webkit ms',
+      'transform':                  'webkit ms',
+      'transform-origin':           'webkit ms',
+      'transition':                 '',
+      'transition-delay':           '',
+      'transition-duration':        '',
+      'transition-property':        '',
+      'transition-timing-function': '',
+      'user-modify':                'webkit moz',
+      'user-select':                'webkit moz ms',
+      'word-break':                 'epub ms',
+      'writing-mode':               'epub ms',
+    };
+    const applyTo = [];
+    let properties = [];
+    let inKeyFrame = false;
+    let started = 0;
+
+    for (const prop in compatiblePrefixes) {
+      const variations = compatiblePrefixes[prop].split(' ').map(s => `-${s}-${prop}`);
+      compatiblePrefixes[prop] = variations;
+      applyTo.push(...variations);
+    }
+
+    parser.addListener('startrule', () => {
+      started++;
+      properties = [];
+    });
+
+    parser.addListener('startkeyframes', event => {
+      started++;
+      inKeyFrame = event.prefix || true;
+      if (inKeyFrame && typeof inKeyFrame === 'string') {
+        inKeyFrame = '-' + inKeyFrame + '-';
+      }
+    });
+
+    parser.addListener('endkeyframes', () => {
+      started--;
+      inKeyFrame = false;
+    });
+
+    parser.addListener('property', event => {
+      if (!started) return;
+      const name = event.property.text;
+      if (inKeyFrame &&
+          typeof inKeyFrame === 'string' &&
+          name.startsWith(inKeyFrame) ||
+          CSSLint.Util.indexOf(applyTo, name) < 0) {
+        return;
+      }
+      properties.push(event.property);
+    });
+
+    parser.addListener('endrule', () => {
+      started = 0;
+      if (!properties.length) return;
+      const propertyGroups = {};
+
+      for (const name of properties) {
+        for (const prop in compatiblePrefixes) {
+          const variations = compatiblePrefixes[prop];
+          if (CSSLint.Util.indexOf(variations, name.text) <= -1) continue;
+
+          if (!propertyGroups[prop]) {
+            propertyGroups[prop] = {
+              full:        variations.slice(0),
+              actual:      [],
+              actualNodes: [],
+            };
+          }
+
+          if (CSSLint.Util.indexOf(propertyGroups[prop].actual, name.text) === -1) {
+            propertyGroups[prop].actual.push(name.text);
+            propertyGroups[prop].actualNodes.push(name);
+          }
+        }
+      }
+
+      for (const prop in propertyGroups) {
+        const value = propertyGroups[prop];
+        const actual = value.actual;
+        if (value.full.length <= actual.length) continue;
+
+        for (const item of value.full) {
+          if (CSSLint.Util.indexOf(actual, item) !== -1) continue;
+
+          const propertiesSpecified =
+            actual.length === 1 ?
+              actual[0] :
+              actual.length === 2 ?
+                actual.join(' and ') :
+                actual.join(', ');
+
+          const {line, col} = value.actualNodes[0];
+          reporter.report(
+            `The property ${item} is compatible with ${propertiesSpecified} and should be included as well.`,
+            line, col, this);
+        }
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'display-property-grouping',
+  name:     'Require properties appropriate for display',
+  desc:     "Certain properties shouldn't be used with certain display property values.",
+  url:      'https://github.com/CSSLint/csslint/wiki/Require-properties-appropriate-for-display',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    const propertiesToCheck = {
+      'display':        1,
+      'float':          'none',
+      'height':         1,
+      'width':          1,
+      'margin':         1,
+      'margin-left':    1,
+      'margin-right':   1,
+      'margin-bottom':  1,
+      'margin-top':     1,
+      'padding':        1,
+      'padding-left':   1,
+      'padding-right':  1,
+      'padding-bottom': 1,
+      'padding-top':    1,
+      'vertical-align': 1,
+    };
+    let properties;
+    let started = 0;
+
+    const startRule = () => {
+      started = 1;
+      properties = {};
+    };
+
+    const property = event => {
+      if (!started) return;
+      const name = event.property.text.toLowerCase();
+      if (name in propertiesToCheck) {
+        properties[name] = {
+          value: event.value.text,
+          line:  event.property.line,
+          col:   event.property.col,
+        };
+      }
+    };
+
+    const reportProperty = (name, display, msg) => {
+      const prop = properties[name];
+      if (!prop) return;
+
+      const toCheck = propertiesToCheck[name];
+      if (typeof toCheck === 'string' && toCheck === prop.value.toLowerCase()) return;
+
+      const {line, col} = prop;
+      reporter.report(msg || `${name} can't be used with display: ${display}.`,
+        line, col, this);
+    };
+
+    const endRule = () => {
+      started = 0;
+      const display = properties.display && properties.display.value;
+      if (!display) return;
+
+      switch (display.toLowerCase()) {
+
+        case 'inline':
+          ['height', 'width', 'margin', 'margin-top', 'margin-bottom']
+            .forEach(p => reportProperty(p, display));
+
+          reportProperty('float', display,
+            'display:inline has no effect on floated elements ' +
+            '(but may be used to fix the IE6 double-margin bug).');
+          break;
+
+        case 'block':
+          // vertical-align should not be used with block
+          reportProperty('vertical-align', display);
+          break;
+
+        case 'inline-block':
+          // float should not be used with inline-block
+          reportProperty('float', display);
+          break;
+
+        default:
+          // margin, float should not be used with table
+          if (display.indexOf('table-') !== 0) {
+            return;
+          }
+          ['margin', 'margin-left', 'margin-right', 'margin-top', 'margin-bottom', 'float']
+            .forEach(p => reportProperty(p, display));
+      }
+    };
+
+    CSSLint.Util.registerBlockEvents(parser, startRule, endRule, property);
+  },
+});
+
+CSSLint.addRule({
+  id:       'duplicate-background-images',
+  name:     'Disallow duplicate background images',
+  desc:     'Every background-image should be unique. Use a common class for e.g. sprites.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-duplicate-background-images',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    const stack = {};
+
+    parser.addListener('property', event => {
+      const name = event.property.text;
+      if (!name.match(/background/i)) return;
+
+      for (const part of event.value.parts) {
+        if (part.type !== 'uri') continue;
+
+        const uri = stack[part.uri];
+        if (uri === undefined) {
+          stack[part.uri] = event;
+          continue;
+        }
+
+        reporter.report(
+          `Background image '${part.uri}' was used multiple times, ` +
+          `first declared at line ${uri.line}, col ${uri.col}.`,
+          event.line, event.col, this);
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'duplicate-properties',
+  name:     'Disallow duplicate properties',
+  desc:     'Duplicate properties must appear one after the other.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-duplicate-properties',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    let properties, lastName;
+    let started = 0;
+
+    const startRule = () => {
+      started = 1;
+      properties = {};
+    };
+
+    const endRule = () => {
+      started = 0;
+      properties = {};
+    };
+
+    const property = event => {
+      if (!started) return;
+      const property = event.property;
+      const name = property.text.toLowerCase();
+      const last = properties[name];
+      if (last && (lastName !== name || last === event.value.text)) {
+        reporter.report(`Duplicate property '${property}' found.`, event.line, event.col, this);
+      }
+      properties[name] = event.value.text;
+      lastName = name;
+    };
+
+    CSSLint.Util.registerBlockEvents(parser, startRule, endRule, property);
+  },
+});
+
+CSSLint.addRule({
+  id:       'empty-rules',
+  name:     'Disallow empty rules',
+  desc:     'Rules without any properties specified should be removed.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-empty-rules',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    let count = 0;
+    parser.addListener('startrule', () => (count = 0));
+    parser.addListener('property', () => count++);
+    parser.addListener('endrule', event => {
+      if (!count) {
+        const {line, col} = event.selectors[0];
+        reporter.report('Rule is empty.', line, col, this);
+      }
+    });
+  },
+
+});
+
+CSSLint.addRule({
+  id:       'errors',
+  name:     'Parsing Errors',
+  desc:     'This rule looks for recoverable syntax errors.',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('error', ({message, line, col}) => {
+      reporter.error(message, line, col, this);
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'fallback-colors',
+  name:     'Require fallback colors',
+  desc:     "For older browsers that don't support RGBA, HSL, or HSLA, provide a fallback color.",
+  url:      'https://github.com/CSSLint/csslint/wiki/Require-fallback-colors',
+  browsers: 'IE6,IE7,IE8',
+
+  init(parser, reporter) {
+    const propertiesToCheck = new Set([
+      'color',
+      'background',
+      'border-color',
+      'border-top-color',
+      'border-right-color',
+      'border-bottom-color',
+      'border-left-color',
+      'border',
+      'border-top',
+      'border-right',
+      'border-bottom',
+      'border-left',
+      'background-color',
+    ]);
+    let lastProperty;
+    const startRule = () => (lastProperty = null);
+
+    CSSLint.Util.registerBlockEvents(parser, startRule, null, event => {
+      const name = event.property.text.toLowerCase();
+      if (!propertiesToCheck.has(name)) {
+        lastProperty = event;
+        return;
+      }
+
+      let colorType = '';
+      for (const part of event.value.parts) {
+        if (part.type !== 'color') continue;
+
+        if (!('alpha' in part || 'hue' in part)) {
+          event.colorType = 'compat';
+          continue;
+        }
+
+        if (/([^)]+)\(/.test(part)) {
+          colorType = RegExp.$1.toUpperCase();
+        }
+
+        if (!lastProperty ||
+            lastProperty.property.text.toLowerCase() !== name ||
+            lastProperty.colorType !== 'compat') {
+          reporter.report(`Fallback ${name} (hex or RGB) should precede ${colorType} ${name}.`,
+            event.line, event.col, this);
+        }
+      }
+      lastProperty = event;
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'floats',
+  name:     'Disallow too many floats',
+  desc:     'This rule tests if the float property is used too many times',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-too-many-floats',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    let count = 0;
+
+    parser.addListener('property', ({property, value}) => {
+      count +=
+        property.text.toLowerCase() === 'float' &&
+        value.text.toLowerCase() !== 'none';
+    });
+
+    parser.addListener('endstylesheet', () => {
+      reporter.stat('floats', count);
+      if (count >= 10) {
+        reporter.rollupWarn(
+          `Too many floats (${count}), you're probably using them for layout. ` +
+          'Consider using a grid system instead.', this);
+      }
+    });
+  },
+
+});
+
+CSSLint.addRule({
+  id:       'font-faces',
+  name:     "Don't use too many web fonts",
+  desc:     'Too many different web fonts in the same stylesheet.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Don%27t-use-too-many-web-fonts',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    let count = 0;
+    parser.addListener('startfontface', () => count++);
+    parser.addListener('endstylesheet', () => {
+      if (count > 5) {
+        reporter.rollupWarn(`Too many @font-face declarations (${count}).`, this);
+      }
+    });
+  },
+
+});
+
+CSSLint.addRule({
+  id:       'font-sizes',
+  name:     'Disallow too many font sizes',
+  desc:     'Checks the number of font-size declarations.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Don%27t-use-too-many-font-size-declarations',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    let count = 0;
+
+    parser.addListener('property', event => {
+      count += event.property.toString() === 'font-size';
+    });
+
+    parser.addListener('endstylesheet', () => {
+      reporter.stat('font-sizes', count);
+      if (count >= 10) {
+        reporter.rollupWarn('Too many font-size declarations (' + count + '), abstraction needed.', this);
+      }
+    });
+  },
+
+});
+
+CSSLint.addRule({
+
+  id:       'gradients',
+  name:     'Require all gradient definitions',
+  desc:     'When using a vendor-prefixed gradient, make sure to use them all.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Require-all-gradient-definitions',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    let gradients;
+
+    parser.addListener('startrule', () => {
+      gradients = {
+        moz:       0,
+        webkit:    0,
+        oldWebkit: 0,
+        o:         0,
+      };
+    });
+
+    parser.addListener('property', event => {
+      if (/-(moz|o|webkit)(?:-(?:linear|radial))-gradient/i.test(event.value)) {
+        gradients[RegExp.$1] = 1;
+      } else if (/-webkit-gradient/i.test(event.value)) {
+        gradients.oldWebkit = 1;
+      }
+    });
+
+    parser.addListener('endrule', event => {
+      const missing = [];
+      if (!gradients.moz) missing.push('Firefox 3.6+');
+      if (!gradients.webkit) missing.push('Webkit (Safari 5+, Chrome)');
+      if (!gradients.oldWebkit) missing.push('Old Webkit (Safari 4+, Chrome)');
+      if (!gradients.o) missing.push('Opera 11.1+');
+      if (missing.length && missing.length < 4) {
+        const {line, col} = event.selectors[0];
+        reporter.report(`Missing vendor-prefixed CSS gradients for ${missing.join(', ')}.`,
+          line, col, this);
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'ids',
+  name:     'Disallow IDs in selectors',
+  desc:     'Selectors should not contain IDs.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-IDs-in-selectors',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('startrule', event => {
+      for (const {line, col, parts} of event.selectors) {
+        const idCount =
+          parts.reduce((sum = 0, {type, modifiers}) =>
+            type === parser.SELECTOR_PART_TYPE ?
+              modifiers.reduce(sum, mod => sum + (mod.type === 'id')) :
+              sum);
+        if (idCount === 1) {
+          reporter.report("Don't use IDs in selectors.", line, col, this);
+        } else if (idCount > 1) {
+          reporter.report(idCount + ' IDs in the selector, really?', line, col, this);
+        }
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'import-ie-limit',
+  name:     '@import limit on IE6-IE9',
+  desc:     'IE6-9 supports up to 31 @import per stylesheet',
+  browsers: 'IE6, IE7, IE8, IE9',
+
+  init(parser, reporter) {
+    const MAX_IMPORT_COUNT = 31;
+    let count = 0;
+    parser.addListener('startpage', () => (count = 0));
+    parser.addListener('import', () => count++);
+    parser.addListener('endstylesheet', () => {
+      if (count > MAX_IMPORT_COUNT) {
+        reporter.rollupError(`Too many @import rules (${count}). IE6-9 supports up to 31 import per stylesheet.`, this);
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'import',
+  name:     'Disallow @import',
+  desc:     "Don't use @import, use <link> instead.",
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-%40import',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('import', ({line, col}) => {
+      reporter.report('@import prevents parallel downloads, use <link> instead.', line, col, this);
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'important',
+  name:     'Disallow !important',
+  desc:     'Be careful when using !important declaration',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-%21important',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    let count = 0;
+
+    parser.addListener('property', event => {
+      if (!event.important) return;
+      count++;
+      reporter.report('Use of !important', event.line, event.col, this);
+    });
+
+    parser.addListener('endstylesheet', () => {
+      reporter.stat('important', count);
+      if (count >= 10) {
+        reporter.rollupWarn(
+          `Too many !important declarations (${count}), ` +
+          'try to use less than 10 to avoid specificity issues.', this);
+      }
+    });
+  },
+
+});
+
+CSSLint.addRule({
+  id:       'known-properties',
+  name:     'Require use of known properties',
+  desc:     'Properties should be known (listed in CSS3 specification) or be a vendor-prefixed property.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Require-use-of-known-properties',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('property', event => {
+      if (event.invalid) {
+        reporter.report(event.invalid.message, event.line, event.col, this);
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'order-alphabetical',
+  name:     'Alphabetical order',
+  desc:     'Assure properties are in alphabetical order',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    let properties;
+    let started = 0;
+
+    const startRule = () => {
+      started = 1;
+      properties = [];
+    };
+
+    const property = event => {
+      if (!started) return;
+      const name = event.property.text;
+      const lowerCasePrefixLessName = name.toLowerCase().replace(/^-.*?-/, '');
+      properties.push(lowerCasePrefixLessName);
+    };
+
+    const endRule = event => {
+      started = 0;
+      if (properties.join(',') !== properties.sort().join(',')) {
+        reporter.report("Rule doesn't have all its properties in alphabetical order.", event.line, event.col, this);
+      }
+    };
+
+    CSSLint.Util.registerBlockEvents(parser, startRule, endRule, property);
+  },
+});
+
+CSSLint.addRule({
+  id:       'outline-none',
+  name:     'Disallow outline: none',
+  desc:     'Use of outline: none or outline: 0 should be limited to :focus rules.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-outline%3Anone',
+  browsers: 'All',
+  tags:     ['Accessibility'],
+
+  init(parser, reporter) {
+    let lastRule;
+
+    const startRule = event => {
+      lastRule = !event.selectors ? null : {
+        line:      event.line,
+        col:       event.col,
+        selectors: event.selectors,
+        propCount: 0,
+        outline:   false,
+      };
+    };
+
+    const property = event => {
+      if (!lastRule) return;
+      const name = event.property.text.toLowerCase();
+      const value = event.value;
+      lastRule.propCount++;
+      if (name === 'outline' && /^(none|0)$/i.test(value)) {
+        lastRule.outline = true;
+      }
+    };
+
+    const endRule = () => {
+      const {outline, selectors, propCount, line, col} = lastRule || {};
+      lastRule = null;
+      if (!outline) return;
+      if (selectors.toString().toLowerCase().indexOf(':focus') === -1) {
+        reporter.report('Outlines should only be modified using :focus.', line, col, this);
+      } else if (propCount === 1) {
+        reporter.report("Outlines shouldn't be hidden unless other visual changes are made.",
+          line, col, this);
+      }
+    };
+
+    CSSLint.Util.registerBlockEvents(parser, startRule, endRule, property);
+  },
+});
+
+CSSLint.addRule({
+  id:       'overqualified-elements',
+  name:     'Disallow overqualified elements',
+  desc:     "Don't use classes or IDs with elements (a.foo or a#foo).",
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-overqualified-elements',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    const classes = {};
+
+    parser.addListener('startrule', event => {
+      for (const selector of event.selectors) {
+        for (const part of selector.parts) {
+          if (part.type !== parser.SELECTOR_PART_TYPE) continue;
+          for (const mod of part.modifiers) {
+            if (part.elementName && mod.type === 'id') {
+              reporter.report('Element (' + part + ') is overqualified, just use ' + mod +
+                              ' without element name.', part.line, part.col, this);
+            } else if (mod.type === 'class') {
+              let classMods = classes[mod];
+              if (!classMods) classMods = classes[mod] = [];
+              classMods.push({modifier: mod, part});
+            }
+          }
+        }
+      }
+    });
+
+    // one use means that this is overqualified
+    parser.addListener('endstylesheet', () => {
+      for (const prop in classes) {
+        const {part, modifier} = classes[prop][0];
+        if (part.elementName && classes[prop].length === 1) {
+          reporter.report(`Element (${part}) is overqualified, just use ${modifier} without element name.`,
+            part.line, part.col, this);
+        }
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'qualified-headings',
+  name:     'Disallow qualified headings',
+  desc:     'Headings should not be qualified (namespaced).',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-qualified-headings',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('startrule', event => {
+      for (const selector of event.selectors) {
+        let first = true;
+        for (const part of selector.parts) {
+          const name = part.elementName;
+          if (!first &&
+              name &&
+              part.type === parser.SELECTOR_PART_TYPE &&
+              /h[1-6]/.test(name.toString())) {
+            reporter.report(`Heading (${name}) should not be qualified.`,
+              part.line, part.col, this);
+          }
+          first = false;
+        }
+      }
+    });
+  },
+
+});
+
+CSSLint.addRule({
+  id:       'regex-selectors',
+  name:     'Disallow selectors that look like regexs',
+  desc:     'Selectors that look like regular expressions are slow and should be avoided.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-selectors-that-look-like-regular-expressions',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('startrule', event => {
+      for (const selector of event.selectors) {
+        for (const part of selector.parts) {
+          if (part.type !== parser.SELECTOR_PART_TYPE) continue;
+          for (const mod of part.modifiers) {
+            if (mod.type !== 'attribute' || !/([~|^$*]=)/.test(mod)) continue;
+            reporter.report(`Attribute selectors with ${RegExp.$1} are slow!`,
+              mod.line, mod.col, this);
+          }
+        }
+      }
+    });
+  },
+
+});
+
+CSSLint.addRule({
+  id:       'rules-count',
+  name:     'Rules Count',
+  desc:     'Track how many rules there are.',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    let count = 0;
+    parser.addListener('startrule', () => count++);
+    parser.addListener('endstylesheet', () => reporter.stat('rule-count', count));
+  },
+});
+
+CSSLint.addRule({
+  id:       'selector-max-approaching',
+  name:     'Warn when approaching the 4095 selector limit for IE',
+  desc:     'Will warn when selector count is >= 3800 selectors.',
+  browsers: 'IE',
+
+  init(parser, reporter) {
+    let count = 0;
+    parser.addListener('startrule', event => (count += event.selectors.length));
+    parser.addListener('endstylesheet', () => {
+      if (count >= 3800) {
+        reporter.report(
+          `You have ${count} selectors. ` +
+          'Internet Explorer supports a maximum of 4095 selectors per stylesheet. ' +
+          'Consider refactoring.', 0, 0, this);
+      }
+    });
+  },
+
+});
+
+CSSLint.addRule({
+  id:       'selector-max',
+  name:     'Error when past the 4095 selector limit for IE',
+  desc:     'Will error when selector count is > 4095.',
+  browsers: 'IE',
+
+  init(parser, reporter) {
+    let count = 0;
+    parser.addListener('startrule', event => (count += event.selectors.length));
+    parser.addListener('endstylesheet', () => {
+      if (count > 4095) {
+        reporter.report(
+          `You have ${count} selectors. ` +
+          'Internet Explorer supports a maximum of 4095 selectors per stylesheet. ' +
+          'Consider refactoring.', 0, 0, this);
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'selector-newline',
+  name:     'Disallow new-line characters in selectors',
+  desc:     'New-line characters in selectors are usually a forgotten comma and not a descendant combinator.',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('startrule', event => {
+      for (const {parts} of event.selectors) {
+        for (let p = 0, pLen = parts.length; p < pLen; p++) {
+          for (let n = p + 1; n < pLen; n++) {
+            if (parts[p].type === 'descendant' &&
+                parts[n].line > parts[p].line) {
+              reporter.report('newline character found in selector (forgot a comma?)',
+                parts[p].line, parts[0].col, this);
+            }
+          }
+        }
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'shorthand',
+  name:     'Require shorthand properties',
+  desc:     'Use shorthand properties where possible.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Require-shorthand-properties',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    const propertiesToCheck = {};
+    const mapping = {
+      margin:  ['margin-top', 'margin-bottom', 'margin-left', 'margin-right'],
+      padding: ['padding-top', 'padding-bottom', 'padding-left', 'padding-right'],
+    };
+    let properties;
+    let started = 0;
+
+    for (const short in mapping) {
+      for (const full of mapping[short]) {
+        propertiesToCheck[full] = short;
+      }
+    }
+
+    const startRule = () => {
+      started = 1;
+      properties = {};
+    };
+
+    const property = event => {
+      if (!started) return;
+      const name = event.property.toString().toLowerCase();
+      if (name in propertiesToCheck) {
+        properties[name] = 1;
+      }
+    };
+
+    const endRule = event => {
+      started = 0;
+      for (const short in mapping) {
+        const fullList = mapping[short];
+        const total = fullList.reduce((sum = 0, name) => sum + (properties[name] ? 1 : 0));
+        if (total === fullList.length) {
+          reporter.report(`The properties ${fullList.join(', ')} can be replaced by ${short}.`,
+            event.line, event.col, this);
+        }
+      }
+    };
+
+    parser.addListener('startrule', startRule);
+    parser.addListener('startfontface', startRule);
+    parser.addListener('property', property);
+    parser.addListener('endrule', endRule);
+    parser.addListener('endfontface', endRule);
+  },
+});
+
+CSSLint.addRule({
+  id:       'star-property-hack',
+  name:     'Disallow properties with a star prefix',
+  desc:     'Checks for the star property hack (targets IE6/7)',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-star-hack',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('property', ({property: {hack, line, col}}) => {
+      if (hack === '*') {
+        reporter.report('Property with star prefix found.', line, col, this);
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'text-indent',
+  name:     'Disallow negative text-indent',
+  desc:     'Checks for text indent less than -99px',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-negative-text-indent',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    let textIndent, direction;
+
+    const startRule = () => {
+      textIndent = false;
+      direction = 'inherit';
+    };
+
+    const endRule = () => {
+      if (textIndent && direction !== 'ltr') {
+        reporter.report(
+          "Negative text-indent doesn't work well with RTL. " +
+          'If you use text-indent for image replacement explicitly set direction for that item to ltr.',
+          textIndent.line, textIndent.col, this);
+      }
+    };
+
+    parser.addListener('startrule', startRule);
+    parser.addListener('startfontface', startRule);
+
+    parser.addListener('property', event => {
+      const name = event.property.toString().toLowerCase();
+      const value = event.value;
+
+      if (name === 'text-indent' && value.parts[0].value < -99) {
+        textIndent = event.property;
+      } else if (name === 'direction' && value.toString().toLowerCase() === 'ltr') {
+        direction = 'ltr';
+      }
+    });
+
+    parser.addListener('endrule', endRule);
+    parser.addListener('endfontface', endRule);
+  },
+});
+
+CSSLint.addRule({
+  id:       'underscore-property-hack',
+  name:     'Disallow properties with an underscore prefix',
+  desc:     'Checks for the underscore property hack (targets IE6)',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-underscore-hack',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('property', ({property: {hack, line, col}}) => {
+      if (hack === '_') {
+        reporter.report('Property with underscore prefix found.', line, col, this);
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'unique-headings',
+  name:     'Headings should only be defined once',
+  desc:     'Headings should be defined only once.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Headings-should-only-be-defined-once',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    const headings = new Array(6).fill(0);
+
+    parser.addListener('startrule', event => {
+      for (const {parts} of event.selectors) {
+        const part = parts[parts.length - 1];
+        if (!part.elementName || !/h([1-6])/i.test(part.elementName)) continue;
+        if (part.modifiers.some(mod => mod.type === 'pseudo')) continue;
+        if (++headings[Number(RegExp.$1) - 1] > 1) {
+          reporter.report(`Heading (${part.elementName}) has already been defined.`,
+            part.line, part.col, this);
+        }
+      }
+    });
+
+    parser.addListener('endstylesheet', () => {
+      const messages = headings
+        .filter(h => h > 1)
+        .map((h, i) => `${h} H${i + 1}s`);
+      if (messages.length) {
+        reporter.rollupWarn(`You have ${messages.join(', ')} defined in this stylesheet.`, this);
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'universal-selector',
+  name:     'Disallow universal selector',
+  desc:     'The universal selector (*) is known to be slow.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-universal-selector',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('startrule', event => {
+      for (const {parts} of event.selectors) {
+        const part = parts[parts.length - 1];
+        if (part.elementName === '*') {
+          reporter.report(this.desc, part.line, part.col, this);
+        }
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'unqualified-attributes',
+  name:     'Disallow unqualified attribute selectors',
+  desc:     'Unqualified attribute selectors are known to be slow.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-unqualified-attribute-selectors',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('startrule', event => {
+      for (const {parts} of event.selectors) {
+        const part = parts[parts.length - 1];
+        if (part.type !== parser.SELECTOR_PART_TYPE) continue;
+        if (part.modifiers.some(mod => mod.type === 'class' || mod.type === 'id')) continue;
+
+        const isUnqualified = !part.elementName || part.elementName === '*';
+        for (const mod of part.modifiers) {
+          if (mod.type === 'attribute' && isUnqualified) {
+            reporter.report(this.desc, part.line, part.col, this);
+          }
+        }
+      }
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'vendor-prefix',
+  name:     'Require standard property with vendor prefix',
+  desc:     'When using a vendor-prefixed property, make sure to include the standard one.',
+  url:      'https://github.com/CSSLint/csslint/wiki/Require-standard-property-with-vendor-prefix',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    const propertiesToCheck = {
+      '-webkit-border-radius':              'border-radius',
+      '-webkit-border-top-left-radius':     'border-top-left-radius',
+      '-webkit-border-top-right-radius':    'border-top-right-radius',
+      '-webkit-border-bottom-left-radius':  'border-bottom-left-radius',
+      '-webkit-border-bottom-right-radius': 'border-bottom-right-radius',
+
+      '-o-border-radius':              'border-radius',
+      '-o-border-top-left-radius':     'border-top-left-radius',
+      '-o-border-top-right-radius':    'border-top-right-radius',
+      '-o-border-bottom-left-radius':  'border-bottom-left-radius',
+      '-o-border-bottom-right-radius': 'border-bottom-right-radius',
+
+      '-moz-border-radius':             'border-radius',
+      '-moz-border-radius-topleft':     'border-top-left-radius',
+      '-moz-border-radius-topright':    'border-top-right-radius',
+      '-moz-border-radius-bottomleft':  'border-bottom-left-radius',
+      '-moz-border-radius-bottomright': 'border-bottom-right-radius',
+
+      '-moz-column-count':    'column-count',
+      '-webkit-column-count': 'column-count',
+
+      '-moz-column-gap':    'column-gap',
+      '-webkit-column-gap': 'column-gap',
+
+      '-moz-column-rule':    'column-rule',
+      '-webkit-column-rule': 'column-rule',
+
+      '-moz-column-rule-style':    'column-rule-style',
+      '-webkit-column-rule-style': 'column-rule-style',
+
+      '-moz-column-rule-color':    'column-rule-color',
+      '-webkit-column-rule-color': 'column-rule-color',
+
+      '-moz-column-rule-width':    'column-rule-width',
+      '-webkit-column-rule-width': 'column-rule-width',
+
+      '-moz-column-width':    'column-width',
+      '-webkit-column-width': 'column-width',
+
+      '-webkit-column-span': 'column-span',
+      '-webkit-columns':     'columns',
+
+      '-moz-box-shadow':    'box-shadow',
+      '-webkit-box-shadow': 'box-shadow',
+
+      '-moz-transform':    'transform',
+      '-webkit-transform': 'transform',
+      '-o-transform':      'transform',
+      '-ms-transform':     'transform',
+
+      '-moz-transform-origin':    'transform-origin',
+      '-webkit-transform-origin': 'transform-origin',
+      '-o-transform-origin':      'transform-origin',
+      '-ms-transform-origin':     'transform-origin',
+
+      '-moz-box-sizing':    'box-sizing',
+      '-webkit-box-sizing': 'box-sizing',
+    };
+    let properties, num, started;
+
+    const startRule = () => {
+      started = 1;
+      properties = {};
+      num = 1;
+    };
+
+    const endRule = () => {
+      started = 0;
+      const needsStandard = [];
+
+      for (const prop in properties) {
+        if (prop in propertiesToCheck) {
+          needsStandard.push({
+            actual: prop,
+            needed: propertiesToCheck[prop],
+          });
+        }
+      }
+
+      for (const {needed, actual} of needsStandard) {
+        const {line, col} = properties[actual][0].name;
+        if (!properties[needed]) {
+          reporter.report(`Missing standard property '${needed}' to go along with '${actual}'.`,
+            line, col, this);
+        } else if (properties[needed][0].pos < properties[actual][0].pos) {
+          reporter.report(`Standard property '${needed}' should come after vendor-prefixed property '${actual}'.`,
+            line, col, this);
+        }
+      }
+    };
+
+    CSSLint.Util.registerBlockEvents(parser, startRule, endRule, event => {
+      if (!started) return;
+      const name = event.property.text.toLowerCase();
+      let prop = properties[name];
+      if (!prop) prop = properties[name] = [];
+      prop.push({
+        name:  event.property,
+        value: event.value,
+        pos:   num++,
+      });
+    });
+  },
+});
+
+CSSLint.addRule({
+  id:       'zero-units',
+  name:     'Disallow units for 0 values',
+  desc:     "You don't need to specify units when a value is 0.",
+  url:      'https://github.com/CSSLint/csslint/wiki/Disallow-units-for-zero-values',
+  browsers: 'All',
+
+  init(parser, reporter) {
+    parser.addListener('property', event => {
+      for (const {units, type, value, line, col} of event.value.parts) {
+        if ((units || type === 'percentage') && value === 0 && type !== 'time') {
+          reporter.report("Values of 0 shouldn't have units specified.", line, col, this);
+        }
+      }
+    });
+  },
+});
+
+//endregion
diff --git a/vendor-overwrites/csslint/parserlib.js b/vendor-overwrites/csslint/parserlib.js
new file mode 100644
index 00000000..aa722c1f
--- /dev/null
+++ b/vendor-overwrites/csslint/parserlib.js
@@ -0,0 +1,5963 @@
+/*
+Modded by tophf <github.com/tophf>
+========== Original disclaimer:
+
+Parser-Lib
+Copyright (c) 2009-2016 Nicholas C. Zakas. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+'use strict';
+/* eslint-disable class-methods-use-this */
+
+self.parserlib = (() => {
+
+  //region Types
+
+  const TYPES = {
+    DEFAULT_TYPE: 0,
+    COMBINATOR_TYPE: 1,
+    MEDIA_FEATURE_TYPE: 2,
+    MEDIA_QUERY_TYPE: 3,
+    PROPERTY_NAME_TYPE: 4,
+    PROPERTY_VALUE_TYPE: 5,
+    PROPERTY_VALUE_PART_TYPE: 6,
+    SELECTOR_TYPE: 7,
+    SELECTOR_PART_TYPE: 8,
+    SELECTOR_SUB_PART_TYPE: 9,
+  };
+
+  const UNITS = {
+    em:   'length',
+    rem:  'length',
+    ex:   'length',
+    px:   'length',
+    cm:   'length',
+    mm:   'length',
+    in:   'length',
+    pt:   'length',
+    pc:   'length',
+    ch:   'length',
+    vh:   'length',
+    vw:   'length',
+    vmax: 'length',
+    vmin: 'length',
+    fr:   'length',
+
+    deg:  'angle',
+    rad:  'angle',
+    grad: 'angle',
+    turn: 'angle',
+
+    ms:   'time',
+    s:    'time',
+
+    hz:   'frequency',
+    khz:  'frequency',
+
+    dpi:  'resolution',
+    dpcm: 'resolution',
+  };
+
+  //endregion
+  //region Properties
+
+  const Properties = {
+    // A
+    'align-items':               'normal | stretch | <baseline-position> | [ <overflow-position>? <self-position> ]',
+    'align-content':             '<align-content>',
+    'align-self':                '<align-self>',
+    'all':                       'initial | inherit | unset',
+    'alignment-adjust':          'auto | baseline | before-edge | text-before-edge | middle | central | ' +
+                                 'after-edge | text-after-edge | ideographic | alphabetic | hanging | ' +
+                                 'mathematical | <percentage> | <length>',
+    'alignment-baseline':        'auto | baseline | use-script | before-edge | text-before-edge | ' +
+                                 'after-edge | text-after-edge | central | middle | ideographic | alphabetic | ' +
+                                 'hanging | mathematical',
+    'animation':                 '[ <time> || <single-timing-function> || <time> || [ infinite | <number> ] || ' +
+                                 '<single-animation-direction> || <single-animation-fill-mode> || ' +
+                                 '[ running | paused ] || [ none | <ident> | <string> ] ]#',
+    'animation-delay':           '<time>#',
+    'animation-direction':       '<single-animation-direction>#',
+    'animation-duration':        '<time>#',
+    'animation-fill-mode':       '<single-animation-fill-mode>#',
+    'animation-iteration-count': '[ <number> | infinite ]#',
+    'animation-name':            '[ none | <single-animation-name> ]#',
+    'animation-play-state':      '[ running | paused ]#',
+    'animation-timing-function': '<single-timing-function>#',
+
+    'appearance':         'none | auto',
+    '-moz-appearance':    'none | button | button-arrow-down | button-arrow-next | button-arrow-previous | ' +
+                          'button-arrow-up | button-bevel | button-focus | caret | checkbox | checkbox-container | ' +
+                          'checkbox-label | checkmenuitem | dualbutton | groupbox | listbox | listitem | ' +
+                          'menuarrow | menubar | menucheckbox | menuimage | menuitem | menuitemtext | menulist | ' +
+                          'menulist-button | menulist-text | menulist-textfield | menupopup | menuradio | ' +
+                          'menuseparator | meterbar | meterchunk | progressbar | progressbar-vertical | ' +
+                          'progresschunk | progresschunk-vertical | radio | radio-container | radio-label | ' +
+                          'radiomenuitem | range | range-thumb | resizer | resizerpanel | scale-horizontal | ' +
+                          'scalethumbend | scalethumb-horizontal | scalethumbstart | scalethumbtick | ' +
+                          'scalethumb-vertical | scale-vertical | scrollbarbutton-down | scrollbarbutton-left | ' +
+                          'scrollbarbutton-right | scrollbarbutton-up | scrollbarthumb-horizontal | ' +
+                          'scrollbarthumb-vertical | scrollbartrack-horizontal | scrollbartrack-vertical | ' +
+                          'searchfield | separator | sheet | spinner | spinner-downbutton | spinner-textfield | ' +
+                          'spinner-upbutton | splitter | statusbar | statusbarpanel | tab | tabpanel | tabpanels | ' +
+                          'tab-scroll-arrow-back | tab-scroll-arrow-forward | textfield | textfield-multiline | ' +
+                          'toolbar | toolbarbutton | toolbarbutton-dropdown | toolbargripper | toolbox | tooltip | ' +
+                          'treeheader | treeheadercell | treeheadersortarrow | treeitem | treeline | treetwisty | ' +
+                          'treetwistyopen | treeview | -moz-mac-unified-toolbar | -moz-win-borderless-glass | ' +
+                          '-moz-win-browsertabbar-toolbox | -moz-win-communicationstext | ' +
+                          '-moz-win-communications-toolbox | -moz-win-exclude-glass | -moz-win-glass | ' +
+                          '-moz-win-mediatext | -moz-win-media-toolbox | -moz-window-button-box | ' +
+                          '-moz-window-button-box-maximized | -moz-window-button-close | ' +
+                          '-moz-window-button-maximize | -moz-window-button-minimize | -moz-window-button-restore | ' +
+                          '-moz-window-frame-bottom | -moz-window-frame-left | -moz-window-frame-right | ' +
+                          '-moz-window-titlebar | -moz-window-titlebar-maximized',
+    '-ms-appearance':     'none | icon | window | desktop | workspace | document | tooltip | dialog | button | ' +
+                          'push-button | hyperlink | radio | radio-button | checkbox | menu-item | tab | menu | ' +
+                          'menubar | pull-down-menu | pop-up-menu | list-menu | radio-group | checkbox-group | ' +
+                          'outline-tree | range | field | combo-box | signature | password | normal',
+    '-webkit-appearance': 'none | button | button-bevel | caps-lock-indicator | caret | checkbox | ' +
+                          'default-button | listbox | listitem | media-fullscreen-button | media-mute-button | ' +
+                          'media-play-button | media-seek-back-button | media-seek-forward-button | media-slider | ' +
+                          'media-sliderthumb | menulist | menulist-button | menulist-text | menulist-textfield | ' +
+                          'push-button | radio | searchfield | searchfield-cancel-button | searchfield-decoration | ' +
+                          'searchfield-results-button | searchfield-results-decoration | slider-horizontal | ' +
+                          'slider-vertical | sliderthumb-horizontal | sliderthumb-vertical | square-button | ' +
+                          'textarea | textfield | scrollbarbutton-down | scrollbarbutton-left | ' +
+                          'scrollbarbutton-right | scrollbarbutton-up | scrollbargripper-horizontal | ' +
+                          'scrollbargripper-vertical | scrollbarthumb-horizontal | scrollbarthumb-vertical | ' +
+                          'scrollbartrack-horizontal | scrollbartrack-vertical',
+    '-o-appearance':      'none | window | desktop | workspace | document | tooltip | dialog | button | ' +
+                          'push-button | hyperlink | radio | radio-button | checkbox | menu-item | tab | menu | ' +
+                          'menubar | pull-down-menu | pop-up-menu | list-menu | radio-group | checkbox-group | ' +
+                          'outline-tree | range | field | combo-box | signature | password | normal',
+
+    'azimuth': '<azimuth>',
+
+    // B
+    'backface-visibility':     'visible | hidden',
+    'background':              '[ <bg-layer> , ]* <final-bg-layer>',
+    'background-attachment':   '<attachment>#',
+    'background-blend-mode':   '<blend-mode>',
+    'background-clip':         '<box>#',
+    'background-color':        '<color>',
+    'background-image':        '<bg-image>#',
+    'background-origin':       '<box>#',
+    'background-position':     '<bg-position>',
+    'background-repeat':       '<repeat-style>#',
+    'background-size':         '<bg-size>#',
+    'baseline-shift':          'baseline | sub | super | <percentage> | <length>',
+    'behavior':                1,
+    'binding':                 1,
+    'bleed':                   '<length>',
+    'bookmark-label':          '<content-list>',
+    'bookmark-level':          'none | <integer>',
+    'bookmark-state':          'open | closed',
+    'bookmark-target':         'none | <uri> | attr()',
+    'border':                  '<border-width> || <border-style> || <color>',
+    'border-bottom':           '<border-width> || <border-style> || <color>',
+    'border-bottom-color':     '<color>',
+    'border-bottom-left-radius':  '<x-one-radius>',
+    'border-bottom-right-radius': '<x-one-radius>',
+    'border-bottom-style':     '<border-style>',
+    'border-bottom-width':     '<border-width>',
+    'border-collapse':         'collapse | separate',
+    'border-color':            '<color>{1,4}',
+    'border-image':            '[ none | <image> ] || <border-image-slice> ' +
+                               '[ / <border-image-width> | / <border-image-width>? / <border-image-outset> ]? || ' +
+                               '<border-image-repeat>',
+    'border-image-outset':     '<border-image-outset>',
+    'border-image-repeat':     '<border-image-repeat>',
+    'border-image-slice':      '<border-image-slice>',
+    'border-image-source':     '<image> | none',
+    'border-image-width':      '<border-image-width>',
+    'border-left':             '<border-width> || <border-style> || <color>',
+    'border-left-color':       '<color>',
+    'border-left-style':       '<border-style>',
+    'border-left-width':       '<border-width>',
+    'border-radius':           '<border-radius>',
+    'border-right':            '<border-width> || <border-style> || <color>',
+    'border-right-color':      '<color>',
+    'border-right-style':      '<border-style>',
+    'border-right-width':      '<border-width>',
+    'border-spacing':          '<length>{1,2}',
+    'border-style':            '<border-style>{1,4}',
+    'border-top':              '<border-width> || <border-style> || <color>',
+    'border-top-color':        '<color>',
+    'border-top-left-radius':  '<x-one-radius>',
+    'border-top-right-radius': '<x-one-radius>',
+    'border-top-style':        '<border-style>',
+    'border-top-width':        '<border-width>',
+    'border-width':            '<border-width>{1,4}',
+    'bottom':                  '<margin-width>',
+    'box-decoration-break':    'slice | clone',
+    'box-shadow':              '<box-shadow>',
+    'box-sizing':              'content-box | border-box',
+    'break-after':             'auto | always | avoid | left | right | page | column | avoid-page | avoid-column',
+    'break-before':            'auto | always | avoid | left | right | page | column | avoid-page | avoid-column',
+    'break-inside':            'auto | avoid | avoid-page | avoid-column',
+
+    '-moz-box-align':               'start | end | center | baseline | stretch',
+    '-moz-box-decoration-break':    'slice | clone',
+    '-moz-box-direction':           'normal | reverse',
+    '-moz-box-flex':                '<number>',
+    '-moz-box-flex-group':          '<integer>',
+    '-moz-box-lines':               'single | multiple',
+    '-moz-box-ordinal-group':       '<integer>',
+    '-moz-box-orient':              'horizontal | vertical | inline-axis | block-axis',
+    '-moz-box-pack':                'start | end | center | justify',
+    '-o-box-decoration-break':      'slice | clone',
+    '-webkit-box-align':            'start | end | center | baseline | stretch',
+    '-webkit-box-decoration-break': 'slice | clone',
+    '-webkit-box-direction':        'normal | reverse',
+    '-webkit-box-flex':             '<number>',
+    '-webkit-box-flex-group':       '<integer>',
+    '-webkit-box-lines':            'single | multiple',
+    '-webkit-box-ordinal-group':    '<integer>',
+    '-webkit-box-orient':           'horizontal | vertical | inline-axis | block-axis',
+    '-webkit-box-pack':             'start | end | center | justify',
+
+    // C
+    'caret-color':       'auto | <color>',
+    'caption-side':      'top | bottom',
+    'clear':             'none | right | left | both',
+    'clip':              'rect() | inset-rect() | auto',
+    'clip-path':         '<clip-source> | <clip-path> | none',
+    'clip-rule':         'nonzero | evenodd',
+    'color':             '<color>',
+    'color-interpolation':         'auto | sRGB | linearRGB',
+    'color-interpolation-filters': 'auto | sRGB | linearRGB',
+    'color-profile':     1,
+    'color-rendering':   'auto | optimizeSpeed | optimizeQuality',
+    'column-count':      '<integer> | auto',
+    'column-fill':       'auto | balance',
+    'column-gap':        '<column-gap>',
+    'column-rule':       '<border-width> || <border-style> || <color>',
+    'column-rule-color': '<color>',
+    'column-rule-style': '<border-style>',
+    'column-rule-width': '<border-width>',
+    'column-span':       'none | all',
+    'column-width':      '<length> | auto',
+    'columns':           1,
+    'content':           'normal | none | <content-list> [ / <string> ]?',
+    'counter-increment': 1,
+    'counter-reset':     1,
+    'crop':              'rect() | inset-rect() | auto',
+    'cue':               'cue-after | cue-before',
+    'cue-after':         1,
+    'cue-before':        1,
+    'cursor':            '[ <uri> [ <number> <number> ]? , ]* ' +
+                         '[ auto | default | none | context-menu | help | pointer | progress | wait | ' +
+                         'cell | crosshair | text | vertical-text | alias | copy | move | no-drop | ' +
+                         'not-allowed | grab | grabbing | e-resize | n-resize | ne-resize | nw-resize | ' +
+                         's-resize | se-resize | sw-resize | w-resize | ew-resize | ns-resize | ' +
+                         'nesw-resize | nwse-resize | col-resize | row-resize | all-scroll | ' +
+                         'zoom-in | zoom-out ]',
+
+    // D
+    'direction': 'ltr | rtl',
+    'display':   'inline | block | list-item | inline-block | table | inline-table | ' +
+                 'table-row-group | table-header-group | table-footer-group | table-row | ' +
+                 'table-column-group | table-column | table-cell | table-caption | grid | ' +
+                 'inline-grid | run-in | ruby | ruby-base | ruby-text | ruby-base-container | ' +
+                 'ruby-text-container | contents | none | -moz-box | -moz-inline-block | ' +
+                 '-moz-inline-box | -moz-inline-grid | -moz-inline-stack | -moz-inline-table | ' +
+                 '-moz-grid | -moz-grid-group | -moz-grid-line | -moz-groupbox | -moz-deck | ' +
+                 '-moz-popup | -moz-stack | -moz-marker | -webkit-box | -webkit-inline-box | ' +
+                 '-ms-flexbox | -ms-inline-flexbox | flex | -webkit-flex | inline-flex | ' +
+                 '-webkit-inline-flex',
+
+    'dominant-baseline':          'auto | use-script | no-change | reset-size | ideographic | alphabetic | ' +
+                                  'hanging | mathematical | central | middle | text-after-edge | text-before-edge',
+    'drop-initial-after-adjust':  'central | middle | after-edge | text-after-edge | ideographic | alphabetic | ' +
+                                  'mathematical | <percentage> | <length>',
+    'drop-initial-after-align':   'baseline | use-script | before-edge | text-before-edge | after-edge | ' +
+                                  'text-after-edge | central | middle | ideographic | alphabetic | hanging | ' +
+                                  'mathematical',
+    'drop-initial-before-adjust': 'before-edge | text-before-edge | central | middle | hanging | mathematical | ' +
+                                  '<percentage> | <length>',
+    'drop-initial-before-align':  'caps-height | baseline | use-script | before-edge | text-before-edge | ' +
+                                  'after-edge | text-after-edge | central | middle | ideographic | alphabetic | ' +
+                                  'hanging | mathematical',
+    'drop-initial-size':          'auto | line | <length> | <percentage>',
+    'drop-initial-value':         '<integer>',
+
+    // E
+    'elevation':         '<angle> | below | level | above | higher | lower',
+    'empty-cells':       'show | hide',
+    'enable-background': 1,
+
+    // F
+    'fill':           '<paint>',
+    'fill-opacity':   '<opacity-value>',
+    'fill-rule':      'nonzero | evenodd',
+    'filter':         '<filter-function-list> | none',
+    'fit':            'fill | hidden | meet | slice',
+    'fit-position':   1,
+    'flex':           '<flex-shorthand>',
+    'flex-basis':     '<width>',
+    'flex-direction': 'row | row-reverse | column | column-reverse',
+    'flex-flow':      '<flex-direction> || <flex-wrap>',
+    'flex-grow':      '<number>',
+    'flex-shrink':    '<number>',
+    'flex-wrap':      'nowrap | wrap | wrap-reverse',
+    'float':          'left | right | none',
+    'float-offset':   1,
+    'flood-color':    1,
+    'flood-opacity':  '<opacity-value>',
+    'font':           '<font-shorthand> | caption | icon | menu | message-box | small-caption | status-bar',
+    'font-family':    '<font-family>',
+    'font-feature-settings':   '<feature-tag-value> | normal',
+    'font-kerning':            'auto | normal | none',
+    'font-size':               '<font-size>',
+    'font-size-adjust':        '<number> | none',
+    'font-stretch':            '<font-stretch>',
+    'font-style':              '<font-style>',
+    'font-variant':            '<font-variant> | normal | none',
+    'font-variant-alternates': '<font-variant-alternates> | normal',
+    'font-variant-caps':       '<font-variant-caps> | normal',
+    'font-variant-east-asian': '<font-variant-east-asian> | normal',
+    'font-variant-ligatures':  '<font-variant-ligatures> | normal | none',
+    'font-variant-numeric':    '<font-variant-numeric> | normal',
+    'font-variant-position':   'normal | sub | super',
+    'font-weight':             '<font-weight>',
+    '-ms-flex-align': 'start | end | center | stretch | baseline',
+    '-ms-flex-order': '<number>',
+    '-ms-flex-pack':  'start | end | center | justify',
+
+    // G
+    'gap':                          '<row-gap> <column-gap>?',
+    'glyph-orientation-horizontal': '<glyph-angle>',
+    'glyph-orientation-vertical':   'auto | <glyph-angle>',
+
+    'grid': '<grid-template> | <grid-template-rows> / [ auto-flow && dense? ] <grid-auto-columns>? | ' +
+            '[ auto-flow && dense? ] <grid-auto-rows>? / <grid-template-columns>',
+    'grid-area':         '<grid-line> [ / <grid-line> ]{0,3}',
+    'grid-auto-columns': '<grid-auto-columns>',
+    'grid-auto-flow':    '[ row | column ] || dense',
+    'grid-auto-rows':    '<grid-auto-rows>',
+    'grid-column':       '<grid-line> [ / <grid-line> ]?',
+    'grid-column-start': '<grid-line>',
+    'grid-column-end':   '<grid-line>',
+    'grid-row':          '<grid-line> [ / <grid-line> ]?',
+    'grid-row-start':    '<grid-line>',
+    'grid-row-end':      '<grid-line>',
+    'grid-template':     'none | [ <grid-template-rows> / <grid-template-columns> ] | ' +
+                         '[ <line-names>? <string> <track-size>? <line-names>? ]+ [ / <explicit-track-list> ]?',
+    'grid-template-areas':   'none | <string>+',
+    'grid-template-columns': '<grid-template-columns>',
+    'grid-template-rows':    '<grid-template-rows>',
+    'grid-row-gap':          '<row-gap>',
+    'grid-column-gap':       '<column-gap>',
+    'grid-gap':              '<row-gap> <column-gap>?',
+
+    // H
+    'hanging-punctuation': 1,
+    'height':              '<margin-width> | <content-sizing>',
+    'hyphenate-after':     '<integer> | auto',
+    'hyphenate-before':    '<integer> | auto',
+    'hyphenate-character': '<string> | auto',
+    'hyphenate-lines':     'no-limit | <integer>',
+    'hyphenate-resource':  1,
+    'hyphens':             'none | manual | auto',
+
+    // I
+    'icon':              1,
+    'image-orientation': 'angle | auto',
+    'image-rendering':   'auto | optimizeSpeed | optimizeQuality',
+    'image-resolution':  1,
+    'ime-mode':          'auto | normal | active | inactive | disabled',
+    'inline-box-align':  'last | <integer>',
+    'isolation':         'auto | isolate',
+
+    // J
+    'justify-content': '<justify-content>',
+    'justify-items':   'normal | stretch | <baseline-position> | [ <overflow-position>? <self-position> ] | ' +
+                       '[ legacy || [ left | right | center ] ]',
+    'justify-self':    '<justify-self>',
+
+    // K
+    'kerning': 'auto | <length>',
+
+    // L
+    'left':                   '<margin-width>',
+    'letter-spacing':         '<length> | normal',
+    'line-height':            '<line-height>',
+    'line-break':             'auto | loose | normal | strict',
+    'line-stacking':          1,
+    'line-stacking-ruby':     'exclude-ruby | include-ruby',
+    'line-stacking-shift':    'consider-shifts | disregard-shifts',
+    'line-stacking-strategy': 'inline-line-height | block-line-height | max-height | grid-height',
+    'list-style':             1,
+    'list-style-image':       '<uri> | none',
+    'list-style-position':    'inside | outside',
+    'list-style-type':        'disc | circle | square | decimal | decimal-leading-zero | lower-roman | ' +
+                              'upper-roman | lower-greek | lower-latin | upper-latin | armenian | ' +
+                              'georgian | lower-alpha | upper-alpha | none',
+
+    // M
+    'margin':             '<margin-width>{1,4}',
+    'margin-bottom':      '<margin-width>',
+    'margin-left':        '<margin-width>',
+    'margin-right':       '<margin-width>',
+    'margin-top':         '<margin-width>',
+    'mark':               1,
+    'mark-after':         1,
+    'mark-before':        1,
+    'marker':             1,
+    'marker-end':         1,
+    'marker-mid':         1,
+    'marker-start':       1,
+    'marks':              1,
+    'marquee-direction':  1,
+    'marquee-play-count': 1,
+    'marquee-speed':      1,
+    'marquee-style':      1,
+    'mask':               1,
+    'max-height':         '<length> | <percentage> | <content-sizing> | none',
+    'max-width':          '<length> | <percentage> | <content-sizing> | none',
+    'min-height':         '<length> | <percentage> | <content-sizing> | contain-floats | ' +
+                          '-moz-contain-floats | -webkit-contain-floats',
+    'min-width':          '<length> | <percentage> | <content-sizing> | contain-floats | ' +
+                          '-moz-contain-floats | -webkit-contain-floats',
+    'mix-blend-mode':     '<blend-mode>',
+    'move-to':            1,
+
+    // N
+    'nav-down':  1,
+    'nav-index': 1,
+    'nav-left':  1,
+    'nav-right': 1,
+    'nav-up':    1,
+
+    // O
+    'object-fit':      'fill | contain | cover | none | scale-down',
+    'object-position': '<position>',
+    'opacity':         '<opacity-value>',
+    'order':           '<integer>',
+    'orphans':         '<integer>',
+    'outline':         '[ <color> | invert ] || [ auto | <border-style> ] || <border-width>',
+    'outline-color':   '<color> | invert',
+    'outline-offset':  '<length>',
+    'outline-style':   '<border-style> | auto',
+    'outline-width':   '<border-width>',
+    'overflow':        '<overflow>',
+    'overflow-style':  1,
+    'overflow-wrap':   'normal | break-word',
+    'overflow-x':      '<overflow>',
+    'overflow-y':      '<overflow>',
+
+    // P
+    'padding':            '<padding-width>{1,4}',
+    'padding-bottom':     '<padding-width>',
+    'padding-left':       '<padding-width>',
+    'padding-right':      '<padding-width>',
+    'padding-top':        '<padding-width>',
+    'page':               1,
+    'page-break-after':   'auto | always | avoid | left | right',
+    'page-break-before':  'auto | always | avoid | left | right',
+    'page-break-inside':  'auto | avoid',
+    'page-policy':        1,
+    'pause':              1,
+    'pause-after':        1,
+    'pause-before':       1,
+    'perspective':        'none | <length>',
+    'perspective-origin': '<position>',
+    'phonemes':           1,
+    'pitch':              1,
+    'pitch-range':        1,
+    'place-content':      '<align-content> <justify-content>?',
+    'place-items':        '[ normal | stretch | <baseline-position> | <self-position> ] [ normal | stretch | ' +
+                          '<baseline-position> | <self-position> ]?',
+    'place-self':         '<align-self> <justify-self>?',
+    'play-during':        1,
+    'pointer-events':     'auto | none | visiblePainted | visibleFill | visibleStroke | visible | ' +
+                          'painted | fill | stroke | all',
+    'position':           'static | relative | absolute | fixed | sticky | -webkit-sticky',
+    'presentation-level': 1,
+    'punctuation-trim':   1,
+
+    // Q
+    'quotes': 1,
+
+    // R
+    'rendering-intent': 1,
+    'resize':           1,
+    'rest':             1,
+    'rest-after':       1,
+    'rest-before':      1,
+    'richness':         1,
+    'right':            '<margin-width>',
+    'rotate':           'none | <number>{3}? <angle>',
+    'rotation':         1,
+    'rotation-point':   1,
+    'row-gap':          '<row-gap>',
+    'ruby-align':       1,
+    'ruby-overhang':    1,
+    'ruby-position':    1,
+    'ruby-span':        1,
+
+    // S
+    'scale':             'none | <number>{1,3}',
+    'shape-rendering':   'auto | optimizeSpeed | crispEdges | geometricPrecision',
+    'size':              1,
+    'speak':             'normal | none | spell-out',
+    'speak-header':      'once | always',
+    'speak-numeral':     'digits | continuous',
+    'speak-punctuation': 'code | none',
+    'speech-rate':       1,
+    'src':               1,
+    'stop-color':        1,
+    'stop-opacity':      '<opacity-value>',
+    'stress':            1,
+    'string-set':        1,
+    'stroke':            '<paint>',
+    'stroke-dasharray':  'none | <dasharray>',
+    'stroke-dashoffset': '<percentage> | <length>',
+    'stroke-linecap':    'butt | round | square',
+    'stroke-linejoin':   'miter | round | bevel',
+    'stroke-miterlimit': '<miterlimit>',
+    'stroke-opacity':    '<opacity-value>',
+    'stroke-width':      '<percentage> | <length>',
+
+    // T
+    'table-layout':    'auto | fixed',
+    'tab-size':        '<integer> | <length>',
+    'target':          1,
+    'target-name':     1,
+    'target-new':      1,
+    'target-position': 1,
+    'text-align':      'left | right | center | justify | match-parent | start | end',
+    'text-align-last': 1,
+    'text-anchor':     'start | middle | end',
+    'text-decoration':       '<text-decoration-line> || <text-decoration-style> || <text-decoration-color>',
+    'text-decoration-color': '<text-decoration-color>',
+    'text-decoration-line':  '<text-decoration-line>',
+    'text-decoration-skip':  'none | [ objects || [ spaces | [ leading-spaces || trailing-spaces ] ] || ' +
+                             'edges || box-decoration ]',
+    'text-decoration-style': '<text-decoration-style>',
+    'text-emphasis':    1,
+    'text-height':      1,
+    'text-indent':      '<length> | <percentage>',
+    'text-justify':     'auto | none | inter-word | inter-ideograph | inter-cluster | distribute | kashida',
+    'text-outline':     1,
+    'text-overflow':    'clip | ellipsis',
+    'text-rendering':   'auto | optimizeSpeed | optimizeLegibility | geometricPrecision',
+    'text-shadow':      'none | [ [ <color> && <length>{2,3} ] | <length>{2,3} ]#',
+    'text-transform':   'capitalize | uppercase | lowercase | none',
+    'text-wrap':        'normal | none | avoid',
+    'top':              '<margin-width>',
+    'touch-action':     'auto | none | pan-x | pan-y | pan-left | pan-right | pan-up | pan-down | manipulation',
+    'transform':        'none | <transform-function>+',
+    'transform-box':    'border-box | fill-box | view-box',
+    'transform-origin': '<transform-origin>',
+    'transform-style':  'auto | flat | preserve-3d',
+    'transition':       '<transition>#',
+    'transition-delay': '<time>#',
+    'transition-duration': '<time>#',
+    'transition-property': 'none | [ all | <ident> ]#',
+    'transition-timing-function': '<single-timing-function>#',
+    'translate':        'none | <length-percentage> [ <length-percentage> <length>? ]?',
+
+    // U
+    'unicode-range': '<unicode-range>#',
+    'unicode-bidi':  'normal | embed | isolate | bidi-override | isolate-override | plaintext',
+    'user-modify':   'read-only | read-write | write-only',
+    'user-select':   'auto | text | none | contain | all',
+
+    // V
+    'vertical-align':    'auto | use-script | baseline | sub | super | top | text-top | central | middle | ' +
+                         'bottom | text-bottom | <percentage> | <length>',
+    'visibility':        'visible | hidden | collapse',
+    'voice-balance':     1,
+    'voice-duration':    1,
+    'voice-family':      1,
+    'voice-pitch':       1,
+    'voice-pitch-range': 1,
+    'voice-rate':        1,
+    'voice-stress':      1,
+    'voice-volume':      1,
+    'volume':            1,
+
+    // W
+    'white-space':          'normal | pre | nowrap | pre-wrap | pre-line | -pre-wrap |' +
+                            ' -o-pre-wrap | -moz-pre-wrap | -hp-pre-wrap',
+    'white-space-collapse': 1,
+    'widows':               '<integer>',
+    'width':                '<length> | <percentage> | <content-sizing> | auto',
+    'will-change':          '<will-change>',
+    'word-break':           'normal | keep-all | break-all',
+    'word-spacing':         '<length> | normal',
+    'word-wrap':            'normal | break-word',
+    'writing-mode':         'horizontal-tb | vertical-rl | vertical-lr | lr-tb | rl-tb | tb-rl | ' +
+                            'bt-rl | tb-lr | bt-lr | lr-bt | rl-bt | lr | rl | tb',
+
+    // Z
+    'z-index': '<integer> | auto',
+    'zoom':    '<number> | <percentage> | normal',
+  };
+
+  //endregion
+  //region ValidationTypes - definitions
+
+  const ValidationTypes = {
+    simple: {
+      '<absolute-size>': 'xx-small | x-small | small | medium | large | x-large | xx-large',
+
+      '<animateable-feature>': 'scroll-position | contents | <animateable-feature-name>',
+      '<animateable-feature-name>': function (part) {
+        return this['<ident>'](part) &&
+               !/^(unset|initial|inherit|will-change|auto|scroll-position|contents)$/i.test(part);
+      },
+
+      '<angle>': part => part.type === 'angle',
+
+      '<attr-fallback>': part => !/\battr\(/i.test(part.text),
+
+      '<attachment>': 'scroll | fixed | local',
+
+      '<basic-shape>': 'inset() | circle() | ellipse() | polygon()',
+
+      '<bg-image>': '<image> | <gradient> | none',
+
+      '<blend-mode>': 'normal | multiply | screen | overlay | darken | lighten | color-dodge | ' +
+                      'color-burn | hard-light | soft-light | difference | exclusion | hue | ' +
+                      'saturation | color | luminosity',
+
+      '<border-style>': 'none | hidden | dotted | dashed | solid | double | groove | ridge | inset | outset',
+
+      '<border-width>': '<length> | thin | medium | thick',
+
+      '<box>': 'padding-box | border-box | content-box',
+
+      '<clip-source>': '<uri>',
+
+      '<column-gap>': 'normal | <length> | <percentage>',
+
+      '<content-distribution>': 'space-between | space-around | space-evenly | stretch',
+      '<content-position>': 'center | start | end | flex-start | flex-end',
+
+      // https://www.w3.org/TR/css3-sizing/#width-height-keywords
+      '<content-sizing>': 'fill-available | -moz-available | -webkit-fill-available | max-content | ' +
+                          '-moz-max-content | -webkit-max-content | min-content | -moz-min-content | ' +
+                          '-webkit-min-content | fit-content | -moz-fit-content | -webkit-fit-content',
+
+      '<cubic-bezier-timing-function>': 'ease | ease-in | ease-out | ease-in-out | cubic-bezier()',
+
+      '<feature-tag-value>': part => part.type === 'function' && /^[A-Z0-9]{4}$/i.test(part),
+
+      // custom() isn't actually in the spec
+      '<filter-function>': 'blur() | brightness() | contrast() | custom() | drop-shadow() | grayscale() | ' +
+                           'hue-rotate() | invert() | opacity() | saturate() | sepia()',
+
+      '<fixed-breadth>': '<length-percentage>',
+
+      '<flex>': part =>
+        part.type === 'function' ||
+        part.type === 'grid' && part.value >= 0,
+
+      '<flex-basis>': '<width>',
+      '<flex-direction>': 'row | row-reverse | column | column-reverse',
+      '<flex-grow>': '<number>',
+      '<flex-shrink>': '<number>',
+      '<flex-wrap>': 'nowrap | wrap | wrap-reverse',
+
+      '<font-size>': '<absolute-size> | <relative-size> | <length> | <percentage>',
+      '<font-stretch>': 'normal | ultra-condensed | extra-condensed | condensed | semi-condensed | ' +
+                        'semi-expanded | expanded | extra-expanded | ultra-expanded',
+      '<font-style>': 'normal | italic | oblique',
+      '<font-variant-caps>': 'small-caps | all-small-caps | petite-caps | all-petite-caps | ' +
+                             'unicase | titling-caps',
+      '<font-variant-css21>': 'normal | small-caps',
+      '<font-weight>': 'normal | bold | bolder | lighter | ' +
+                       '100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900',
+
+      '<generic-family>': 'serif | sans-serif | cursive | fantasy | monospace',
+
+      '<geometry-box>': '<shape-box> | fill-box | stroke-box | view-box',
+
+      '<glyph-angle>': part => part.type === 'angle' && part.units === 'deg',
+
+      '<gradient>': part =>
+        part.type === 'function' &&
+        /^(?:-(?:ms|moz|o|webkit)-)?(?:repeating-)?(?:radial-|linear-)?gradient/i.test(part),
+
+      //eslint-disable-next-line no-use-before-define
+      '<hex-color>': part => part.tokenType === Tokens.HASH,
+
+      '<icccolor>': 'cielab() | cielch() | cielchab() | icc-color() | icc-named-color()',
+
+      // any identifier
+      '<ident>': part => part.type === 'identifier' || part.wasIdent,
+      '<ident-not-span>': part => (part.type === 'identifier' || part.wasIdent) && !/^span$/i.test(part.value),
+      '<ident-not-generic-family>': function (part) {
+        return this['<ident>'](part) && !this['<generic-family>'](part);
+      },
+
+      '<image>': '<uri>',
+
+      '<inflexible-breadth>': '<length-percentage> | min-content | max-content | auto',
+
+      '<integer>': part => part.type === 'integer',
+
+      '<length>': part =>
+        part.type === 'function' && /^(?:-(?:ms|moz|o|webkit)-)?calc/i.test(part) ||
+        part.type === 'length' ||
+        part.type === 'number' ||
+        part.type === 'integer' ||
+        part.text === '0',
+
+      '<length-percentage>': '<length> | <percentage>',
+
+      '<line>': part => part.type === 'integer',
+
+      '<line-height>': '<number> | <length> | <percentage> | normal',
+
+      '<margin-width>': '<length> | <percentage> | auto',
+
+      '<miterlimit>': function (part) {
+        return this['<number>'](part) && part.value >= 1;
+      },
+
+      '<nonnegative-length-or-percentage>': function (part) {
+        return (this['<length>'](part) || this['<percentage>'](part)) &&
+               (String(part) === '0' || part.type === 'function' || (part.value) >= 0);
+      },
+      '<nonnegative-number-or-percentage>': function (part) {
+        return (this['<number>'](part) || this['<percentage>'](part)) &&
+               (String(part) === '0' || part.type === 'function' || (part.value) >= 0);
+      },
+
+      '<number-percentage>': '<number> | <percentage>',
+
+      '<positive-integer>': function (part) {
+        return this['<number>'](part) && (part.type === 'function' || part.value > 0);
+      },
+
+      //eslint-disable-next-line no-use-before-define
+      '<named-color>': part => lower(part.text) in Colors,
+
+      '<number>': function (part) {
+        return part.type === 'number' || this['<integer>'](part);
+      },
+
+      '<opacity-value>': function (part) {
+        return this['<number>'](part) && part.value >= 0 && part.value <= 1;
+      },
+
+      '<overflow>': 'visible | hidden | scroll | auto',
+
+      '<overflow-position>': 'unsafe | safe',
+
+      '<padding-width>': '<nonnegative-length-or-percentage>',
+
+      '<percentage>': part => part.type === 'percentage' || String(part) === '0',
+
+      '<relative-size>': 'smaller | larger',
+
+      '<row-gap>': '<column-gap>',
+
+      '<self-position>': 'center | start | end | self-start | self-end | flex-start | flex-end',
+
+      '<shape-box>': '<box> | margin-box',
+
+      '<single-animation-direction>': 'normal | reverse | alternate | alternate-reverse',
+      '<single-animation-fill-mode>': 'none | forwards | backwards | both',
+      '<single-animation-name>': function (part) {
+        return this['<ident>'](part) &&
+               /^-?[a-z_][-a-z0-9_]+$/i.test(part) &&
+               !/^(none|unset|initial|inherit)$/i.test(part);
+      },
+
+      '<step-timing-function>': 'step-start | step-end | steps()',
+
+      '<string>': part => part.type === 'string',
+
+      '<text-decoration-color>': '<color>',
+
+      '<text-decoration-style>': 'solid | double | dotted | dashed | wavy',
+
+      '<time>': part => part.type === 'time',
+
+      '<track-breadth>': '<length-percentage> | <flex> | min-content | max-content | auto',
+
+      '<transform-function>': 'matrix() | translate() | translateX() | translateY() | ' +
+                              'scale() | scaleX() | scaleY() | ' +
+                              'rotate() | skew() | skewX() | skewY()',
+
+      '<unicode-range>': part => /^U\+[0-9a-f?]{1,6}(-[0-9a-f?]{1,6})?\s*$/i.test(part),
+
+      '<unit>': part => part.text === '%' || lower(part) in UNITS,
+
+      '<uri>': part => part.type === 'uri',
+
+      '<var>': part => {
+        //eslint-disable-next-line no-use-before-define
+        if (part.tokenType === Tokens.USO_VAR) return true;
+        if (part.type !== 'function' || !part.expr) return false;
+        const subparts = part.expr.parts;
+        return subparts.length &&
+          lower(part.name) === 'var' &&
+          subparts[0].type === 'custom-property' && (
+            subparts.length === 1 ||
+            subparts[1].text === ','
+          );
+      },
+
+      '<width>': '<margin-width>',
+    },
+
+    complex: {
+      '<align-content>': 'normal | <baseline-position> | <content-distribution> | ' +
+                         '<overflow-position>? <content-position>',
+
+      '<align-self>': 'auto | normal | stretch | <baseline-position> | <overflow-position>? <self-position>',
+
+      '<auto-repeat>': 'repeat( [ auto-fill | auto-fit ] , [ <line-names>? <fixed-size> ]+ <line-names>? )',
+
+      '<auto-track-list>': '[ <line-names>? [ <fixed-size> | <fixed-repeat> ] ]* <line-names>? <auto-repeat> ' +
+                           '[ <line-names>? [ <fixed-size> | <fixed-repeat> ] ]* <line-names>?',
+
+      '<azimuth>': '<angle> | [ [ left-side | far-left | left | center-left | center | center-right | ' +
+                   'right | far-right | right-side ] || behind ] | leftwards | rightwards',
+
+      '<baseline-position>': '[ first | last ]? baseline',
+
+      '<bg-layer>':
+        '<bg-image> || <bg-position> [ / <bg-size> ]? || <repeat-style> || <attachment> || <box>{1,2}',
+
+      '<bg-position>':
+        '[ center | [ left | right ] <length-percentage>? ] && [ center | [ top | bottom ] <length-percentage>? ] | ' +
+        '[ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ] | ' +
+        '[ left | center | right | top | bottom | <length-percentage> ]',
+
+      '<bg-size>': '[ <length> | <percentage> | auto ]{1,2} | cover | contain',
+
+      '<border-image-outset>': '[ <length> | <number> ]{1,4}',
+      '<border-image-repeat>': '[ stretch | repeat | round | space ]{1,2}',
+      '<border-image-slice>': Matcher =>
+        // [<number> | <percentage>]{1,4} && fill?
+        // but 'fill' can appear between any of the numbers
+        Matcher.many(
+          [true],
+          Matcher.cast('<nonnegative-number-or-percentage>'),
+          Matcher.cast('<nonnegative-number-or-percentage>'),
+          Matcher.cast('<nonnegative-number-or-percentage>'),
+          Matcher.cast('<nonnegative-number-or-percentage>'),
+          'fill'),
+      '<border-image-width>': '[ <length> | <percentage> | <number> | auto ]{1,4}',
+      '<border-radius>': '<nonnegative-length-or-percentage>{1,4} [ / <nonnegative-length-or-percentage>{1,4} ]?',
+
+      '<box-shadow>': 'none | <shadow>#',
+
+      '<clip-path>': '<basic-shape> || <geometry-box>',
+
+      '<color>': 'rgb() | rgba() | hsl() | hsla() | hwb() | gray() | device-cmyk() | color() | ' +
+                 '<hex-color> | <named-color>',
+
+      '<color-adjuster>': 'red() | green() | blue() | alpha() | a() | rgb() | hue() | ' +
+                          'saturation() | lightness() | whiteness() | blackness() | ' +
+                          'tint() | shade() | blend() | blenda() | contrast()',
+
+      '<content-list>': '[ <string> | <image> | attr() | content() | leader() | ' +
+                        '[ open-quote | close-quote | no-open-quote | no-close-quote ] | ' +
+                        '[ target-counter() | target-counters() | target-text() ] ]+',
+
+      // "list of comma and/or white space separated <length>s and
+      // <percentage>s".  There is a non-negative constraint.
+      '<dasharray>': Matcher =>
+         Matcher.cast('<nonnegative-length-or-percentage>')
+           .braces(1, Infinity, '#', Matcher.cast(',').question()),
+
+      '<explicit-track-list>'  : '[ <line-names>? <track-size> ]+ <line-names>?',
+
+      '<family-name>': '<string> | <ident-not-generic-family> <ident>*',
+
+      '<filter-function-list>': '[ <filter-function> | <uri> ]+',
+
+      '<final-bg-layer>':
+        '<color> || <bg-image> || <bg-position> [ / <bg-size> ]? || <repeat-style> || <attachment> || <box>{1,2}',
+
+      '<fixed-repeat>': 'repeat( [ <positive-integer> ] , [ <line-names>? <fixed-size> ]+ <line-names>? )',
+
+      '<fixed-size>': '<fixed-breadth> | ' +
+                      'minmax( <fixed-breadth> , <track-breadth> ) | ' +
+                      'minmax( <inflexible-breadth> , <fixed-breadth> )',
+
+      '<flex-shorthand>': 'none | [ <flex-grow> <flex-shrink>? || <flex-basis> ]',
+
+      '<font-family>': '[ <generic-family> | <family-name> ]#',
+
+      '<font-shorthand>': '[ <font-style> || <font-variant-css21> || <font-weight> || <font-stretch> ]? ' +
+                          '<font-size> [ / <line-height> ]? <font-family>',
+
+      '<font-variant-alternates>': 'stylistic() || historical-forms || styleset() || ' +
+                                   'character-variant() || swash() || ornaments() || annotation()',
+
+      '<font-variant-ligatures>': '[ common-ligatures | no-common-ligatures ] || ' +
+                                  '[ discretionary-ligatures | no-discretionary-ligatures ] || ' +
+                                  '[ historical-ligatures | no-historical-ligatures ] || ' +
+                                  '[ contextual | no-contextual ]',
+
+      '<font-variant-numeric>': '[ lining-nums | oldstyle-nums ] || ' +
+                                '[ proportional-nums | tabular-nums ] || ' +
+                                '[ diagonal-fractions | stacked-fractions ] || ' +
+                                'ordinal || slashed-zero',
+
+      '<font-variant-east-asian>': '[ jis78 | jis83 | jis90 | jis04 | simplified | traditional ] || ' +
+                                   '[ full-width | proportional-width ] || ruby',
+
+      '<font-variant>': '<font-variant-ligatures> || <font-variant-alternates> || <font-variant-caps> || ' +
+                        '<font-variant-numeric> || <font-variant-east-asian>',
+
+      '<grid-auto-columns>': '<track-size>+',
+      '<grid-auto-rows>': '<track-size>+',
+
+      '<grid-line>': 'auto | <ident-not-span> | [ <integer> && <ident-not-span>? ] | ' +
+                     '[ span && [ <integer> || <ident-not-span> ] ]',
+
+      '<grid-template>': 'none | [ <grid-template-rows> / <grid-template-columns> ] | ' +
+                         '[ <line-names>? <string> <track-size>? <line-names>? ]+ ' +
+                         '[ / <explicit-track-list> ]?',
+      '<grid-template-columns>': 'none | <track-list> | <auto-track-list>',
+      '<grid-template-rows>': '<grid-template-columns>',
+
+      '<justify-content>': 'normal | <content-distribution> | <overflow-position>? ' +
+                           '[ <content-position> | left | right ]',
+
+      '<justify-self>': 'auto | normal | stretch | <baseline-position> | <overflow-position>? ' +
+                        '[ <self-position> | left | right ]',
+
+      '<line-names>': '<ident-not-span>*',
+
+      '<paint>': 'none | child | child() | <color> | ' +
+                 '<uri> [ none | currentColor | <color> ]? | ' +
+                 'context-fill | context-stroke',
+
+      // Because our `alt` combinator is ordered, we need to test these
+      // in order from longest possible match to shortest.
+      '<position>': '[ [ left | right ] <length-percentage> ] && [ [ top | bottom ] <length-percentage> ] | ' +
+                    '[ left | center | right | <length-percentage> ] ' +
+                    '[ top | center | bottom | <length-percentage> ]? | ' +
+                    '[ left | center | right ] || [ top | center | bottom ]',
+
+      '<repeat-style>': 'repeat-x | repeat-y | [ repeat | space | round | no-repeat ]{1,2}',
+
+      '<rgb-color>': '<number>{3} [ / <nonnegative-number-or-percentage> ]? | ' +
+                     '<percentage>{3} [ / <nonnegative-number-or-percentage> ]? | ' +
+                     '<number>#{3} [ , <nonnegative-number-or-percentage> ]? | ' +
+                     '<percentage>#{3} [ , <nonnegative-number-or-percentage> ]?',
+
+      '<hsl-color>': '[ <number> | <angle> ] <percentage>{2} [ / <nonnegative-number-or-percentage> ]? | ' +
+                     '[ <number> | <angle> ] , <percentage>#{2} [ , <nonnegative-number-or-percentage> ]?',
+
+      // inset? && [ <length>{2,4} && <color>? ]
+      '<shadow>': Matcher =>
+        Matcher.many(
+          [true],
+          Matcher.cast('<length>').braces(2, 4),
+          'inset',
+          '<color>'),
+
+      '<single-timing-function>': 'linear | <cubic-bezier-timing-function> | <step-timing-function> | frames()',
+
+      '<text-decoration-line>': 'none | [ underline || overline || line-through || blink ]',
+
+      '<track-list>': '[ <line-names>? [ <track-size> | <track-repeat> ] ]+ <line-names>?',
+
+      '<track-repeat>': 'repeat( [ <positive-integer> ] , [ <line-names>? <track-size> ]+ <line-names>? )',
+
+      '<track-size>': '<track-breadth> | minmax( <inflexible-breadth> , <track-breadth> ) | ' +
+                      'fit-content( <length-percentage> )',
+
+      '<transform-origin>': '[ left | center | right | <length-percentage> ] ' +
+                            '[ top | center | bottom | <length-percentage> ] <length>? | ' +
+                            '[ left | center | right | top | bottom | <length-percentage> ] | ' +
+                            '[ [ center | left | right ] && [ center | top | bottom ] ] <length>?',
+
+      '<transition>': '[ none | [ all | <ident> ]# ] || <time> || <single-timing-function> || <time>',
+
+      '<will-change>': 'auto | <animateable-feature>#',
+
+      '<x-one-radius>': '[ <length> | <percentage> ]{1,2}',
+    },
+
+    functions: {
+      'attr': '<ident> [ string | color | url | integer | number | length | angle | time | frequency | <unit> ]? ' +
+              '[ , <attr-fallback> ]?',
+
+      'rgb':  '<rgb-color>',
+      'rgba': '<rgb-color>',
+      'hsl':  '<hsl-color>',
+      'hsla': '<hsl-color>',
+      'hwb':  '<hsl-color>',
+      'gray': '<number> [ / <nonnegative-number-or-percentage> ]? )',
+      'device-cmyk': '<number-percentage>{4} [ / <nonnegative-number-or-percentage> ]? , <color>?',
+
+      'color':        '[ <color> | [ <number> | <angle> ] ] <color-adjuster>*',
+      'content':      '[ text | before | after | first-letter | marker ]?',
+      'cubic-bezier': '<number>#{4}',
+      'frames':       '<integer>',
+      'steps':        '<integer> [ , [ start | end ] ]?',
+
+      // used in SVG2 <paint>
+      'child': '<integer>',
+
+      'blur':        '<length>',
+      'brightness':  '<number-percentage>',
+      'contrast':    '<number-percentage>',
+      'drop-shadow': '<length>{2,3} && <color>?',
+      'grayscale':   '<number-percentage>',
+      'hue-rotate':  '<angle> | <zero>',
+      'invert':      '<number-percentage>',
+      'opacity':     '<number-percentage>',
+      'saturate':    '<number-percentage>',
+      'sepia':       '<number-percentage>',
+
+      'inset':   '<length-percentage>{1,4} [ round <border-radius> ]?',
+      'circle':  '[ <length-percentage> | closest-side | farthest-side ]? [ at <position> ]?',
+      'ellipse': '[ [ <length-percentage> | closest-side | farthest-side ]{2} ]? [ at <position> ]?',
+      'polygon': '[ [ nonzero | evenodd | inherit ] , ]? [ <length-percentage> <length-percentage> ]#',
+      'rect':    '[ <length> | auto ]#{4}',
+
+      'matrix':     '<number>#{6}',
+      'translate':  '<length-percentage> [ , <length-percentage> ]?',
+      'translateX': '<length-percentage>',
+      'translateY': '<length-percentage>',
+      'scale':      '<number> [ , <number> ]?',
+      'scaleX':     '<number>',
+      'scaleY':     '<number>',
+      'rotate':     '[ <angle> | <zero> ]',
+      'skew':       '[ <angle> | <zero> ] [ , [ <angle> | <zero> ] ]?',
+      'skewX':      '[ <angle> | <zero> ]',
+      'skewY':      '[ <angle> | <zero> ]',
+    },
+
+    functionsMayBeEmpty: new Set([
+      // https://drafts.fxtf.org/filter-effects/#supported-filter-functions
+      // omitted values default to the initial value for interpolation
+      'blur', 'brightness', 'contrast', 'drop-shadow', 'grayscale',
+      'hue-rotate', 'invert', 'opacity', 'saturate', 'sepia',
+    ]),
+  };
+
+  //endregion
+  //region Colors
+
+  const Colors = {
+    aliceblue:            '#f0f8ff',
+    antiquewhite:         '#faebd7',
+    aqua:                 '#00ffff',
+    aquamarine:           '#7fffd4',
+    azure:                '#f0ffff',
+    beige:                '#f5f5dc',
+    bisque:               '#ffe4c4',
+    black:                '#000000',
+    blanchedalmond:       '#ffebcd',
+    blue:                 '#0000ff',
+    blueviolet:           '#8a2be2',
+    brown:                '#a52a2a',
+    burlywood:            '#deb887',
+    cadetblue:            '#5f9ea0',
+    chartreuse:           '#7fff00',
+    chocolate:            '#d2691e',
+    coral:                '#ff7f50',
+    cornflowerblue:       '#6495ed',
+    cornsilk:             '#fff8dc',
+    crimson:              '#dc143c',
+    cyan:                 '#00ffff',
+    darkblue:             '#00008b',
+    darkcyan:             '#008b8b',
+    darkgoldenrod:        '#b8860b',
+    darkgray:             '#a9a9a9',
+    darkgrey:             '#a9a9a9',
+    darkgreen:            '#006400',
+    darkkhaki:            '#bdb76b',
+    darkmagenta:          '#8b008b',
+    darkolivegreen:       '#556b2f',
+    darkorange:           '#ff8c00',
+    darkorchid:           '#9932cc',
+    darkred:              '#8b0000',
+    darksalmon:           '#e9967a',
+    darkseagreen:         '#8fbc8f',
+    darkslateblue:        '#483d8b',
+    darkslategray:        '#2f4f4f',
+    darkslategrey:        '#2f4f4f',
+    darkturquoise:        '#00ced1',
+    darkviolet:           '#9400d3',
+    deeppink:             '#ff1493',
+    deepskyblue:          '#00bfff',
+    dimgray:              '#696969',
+    dimgrey:              '#696969',
+    dodgerblue:           '#1e90ff',
+    firebrick:            '#b22222',
+    floralwhite:          '#fffaf0',
+    forestgreen:          '#228b22',
+    fuchsia:              '#ff00ff',
+    gainsboro:            '#dcdcdc',
+    ghostwhite:           '#f8f8ff',
+    gold:                 '#ffd700',
+    goldenrod:            '#daa520',
+    gray:                 '#808080',
+    grey:                 '#808080',
+    green:                '#008000',
+    greenyellow:          '#adff2f',
+    honeydew:             '#f0fff0',
+    hotpink:              '#ff69b4',
+    indianred:            '#cd5c5c',
+    indigo:               '#4b0082',
+    ivory:                '#fffff0',
+    khaki:                '#f0e68c',
+    lavender:             '#e6e6fa',
+    lavenderblush:        '#fff0f5',
+    lawngreen:            '#7cfc00',
+    lemonchiffon:         '#fffacd',
+    lightblue:            '#add8e6',
+    lightcoral:           '#f08080',
+    lightcyan:            '#e0ffff',
+    lightgoldenrodyellow: '#fafad2',
+    lightgray:            '#d3d3d3',
+    lightgrey:            '#d3d3d3',
+    lightgreen:           '#90ee90',
+    lightpink:            '#ffb6c1',
+    lightsalmon:          '#ffa07a',
+    lightseagreen:        '#20b2aa',
+    lightskyblue:         '#87cefa',
+    lightslategray:       '#778899',
+    lightslategrey:       '#778899',
+    lightsteelblue:       '#b0c4de',
+    lightyellow:          '#ffffe0',
+    lime:                 '#00ff00',
+    limegreen:            '#32cd32',
+    linen:                '#faf0e6',
+    magenta:              '#ff00ff',
+    maroon:               '#800000',
+    mediumaquamarine:     '#66cdaa',
+    mediumblue:           '#0000cd',
+    mediumorchid:         '#ba55d3',
+    mediumpurple:         '#9370db',
+    mediumseagreen:       '#3cb371',
+    mediumslateblue:      '#7b68ee',
+    mediumspringgreen:    '#00fa9a',
+    mediumturquoise:      '#48d1cc',
+    mediumvioletred:      '#c71585',
+    midnightblue:         '#191970',
+    mintcream:            '#f5fffa',
+    mistyrose:            '#ffe4e1',
+    moccasin:             '#ffe4b5',
+    navajowhite:          '#ffdead',
+    navy:                 '#000080',
+    oldlace:              '#fdf5e6',
+    olive:                '#808000',
+    olivedrab:            '#6b8e23',
+    orange:               '#ffa500',
+    orangered:            '#ff4500',
+    orchid:               '#da70d6',
+    palegoldenrod:        '#eee8aa',
+    palegreen:            '#98fb98',
+    paleturquoise:        '#afeeee',
+    palevioletred:        '#db7093',
+    papayawhip:           '#ffefd5',
+    peachpuff:            '#ffdab9',
+    peru:                 '#cd853f',
+    pink:                 '#ffc0cb',
+    plum:                 '#dda0dd',
+    powderblue:           '#b0e0e6',
+    purple:               '#800080',
+    rebeccapurple:        '#663399',
+    red:                  '#ff0000',
+    rosybrown:            '#bc8f8f',
+    royalblue:            '#4169e1',
+    saddlebrown:          '#8b4513',
+    salmon:               '#fa8072',
+    sandybrown:           '#f4a460',
+    seagreen:             '#2e8b57',
+    seashell:             '#fff5ee',
+    sienna:               '#a0522d',
+    silver:               '#c0c0c0',
+    skyblue:              '#87ceeb',
+    slateblue:            '#6a5acd',
+    slategray:            '#708090',
+    slategrey:            '#708090',
+    snow:                 '#fffafa',
+    springgreen:          '#00ff7f',
+    steelblue:            '#4682b4',
+    tan:                  '#d2b48c',
+    teal:                 '#008080',
+    thistle:              '#d8bfd8',
+    tomato:               '#ff6347',
+    turquoise:            '#40e0d0',
+    violet:               '#ee82ee',
+    wheat:                '#f5deb3',
+    white:                '#ffffff',
+    whitesmoke:           '#f5f5f5',
+    yellow:               '#ffff00',
+    yellowgreen:          '#9acd32',
+    // 'currentColor' color keyword
+    // https://www.w3.org/TR/css3-color/#currentcolor
+    currentcolor:         '',
+    transparent:          '#0000',
+
+    // CSS2 system colors
+    // https://www.w3.org/TR/css3-color/#css2-system
+    activeborder: '',
+    activecaption: '',
+    appworkspace: '',
+    background: '',
+    buttonface: '',
+    buttonhighlight: '',
+    buttonshadow: '',
+    buttontext: '',
+    captiontext: '',
+    graytext: '',
+    greytext: '',
+    highlight: '',
+    highlighttext: '',
+    inactiveborder: '',
+    inactivecaption: '',
+    inactivecaptiontext: '',
+    infobackground: '',
+    infotext: '',
+    menu: '',
+    menutext: '',
+    scrollbar: '',
+    threeddarkshadow: '',
+    threedface: '',
+    threedhighlight: '',
+    threedlightshadow: '',
+    threedshadow: '',
+    window: '',
+    windowframe: '',
+    windowtext: '',
+  };
+
+  //endregion
+  //region Tokens
+
+  /*
+   * The following token names are defined in CSS3 Grammar:
+   * https://www.w3.org/TR/css3-syntax/#lexical
+   */
+  const Tokens = [
+    // HTML-style comments
+    {name: 'CDO'},
+    {name: 'CDC'},
+
+    // ignorables
+    {name: 'S', whitespace: true},
+    {name: 'COMMENT', whitespace: true, comment: true, hide: true},
+
+    // attribute equality
+    {name: 'INCLUDES', text: '~='},
+    {name: 'DASHMATCH', text: '|='},
+    {name: 'PREFIXMATCH', text: '^='},
+    {name: 'SUFFIXMATCH', text: '$='},
+    {name: 'SUBSTRINGMATCH', text: '*='},
+
+    // identifier types
+    {name: 'STRING'},
+    {name: 'IDENT'},
+    {name: 'HASH'},
+
+    // at-keywords
+    {name: 'IMPORT_SYM', text: '@import'},
+    {name: 'PAGE_SYM', text: '@page'},
+    {name: 'MEDIA_SYM', text: '@media'},
+    {name: 'FONT_FACE_SYM', text: '@font-face'},
+    {name: 'CHARSET_SYM', text: '@charset'},
+    {name: 'NAMESPACE_SYM', text: '@namespace'},
+    {name: 'SUPPORTS_SYM', text: '@supports'},
+    {name: 'VIEWPORT_SYM', text: ['@viewport', '@-ms-viewport', '@-o-viewport']},
+    {name: 'DOCUMENT_SYM', text: ['@document', '@-moz-document']},
+    {name: 'UNKNOWN_SYM'}, //{ name: "ATKEYWORD"},
+
+    // CSS3 animations
+    {name: 'KEYFRAMES_SYM', text: ['@keyframes', '@-webkit-keyframes', '@-moz-keyframes', '@-o-keyframes']},
+
+    // important symbol
+    {name: 'IMPORTANT_SYM'},
+
+    // measurements
+    {name: 'LENGTH'},
+    {name: 'ANGLE'},
+    {name: 'TIME'},
+    {name: 'FREQ'},
+    {name: 'DIMENSION'},
+    {name: 'PERCENTAGE'},
+    {name: 'NUMBER'},
+
+    // functions
+    {name: 'URI'},
+    {name: 'FUNCTION'},
+
+    // Unicode ranges
+    {name: 'UNICODE_RANGE'},
+
+    /*
+     * The following token names are defined in CSS3 Selectors: https://www.w3.org/TR/css3-selectors/#selector-syntax
+     */
+
+    // invalid string
+    {name: 'INVALID'},
+
+    // combinators
+    {name: 'PLUS', text: '+'},
+    {name: 'GREATER', text: '>'},
+    {name: 'COMMA', text: ','},
+    {name: 'TILDE', text: '~'},
+
+    // modifier
+    {name: 'NOT'},
+    {name: 'ANY', text: ['any', '-webkit-any', '-moz-any']},
+
+    /*
+     * Defined in CSS3 Paged Media
+     */
+    {name: 'TOPLEFTCORNER_SYM', text: '@top-left-corner'},
+    {name: 'TOPLEFT_SYM', text: '@top-left'},
+    {name: 'TOPCENTER_SYM', text: '@top-center'},
+    {name: 'TOPRIGHT_SYM', text: '@top-right'},
+    {name: 'TOPRIGHTCORNER_SYM', text: '@top-right-corner'},
+    {name: 'BOTTOMLEFTCORNER_SYM', text: '@bottom-left-corner'},
+    {name: 'BOTTOMLEFT_SYM', text: '@bottom-left'},
+    {name: 'BOTTOMCENTER_SYM', text: '@bottom-center'},
+    {name: 'BOTTOMRIGHT_SYM', text: '@bottom-right'},
+    {name: 'BOTTOMRIGHTCORNER_SYM', text: '@bottom-right-corner'},
+    {name: 'LEFTTOP_SYM', text: '@left-top'},
+    {name: 'LEFTMIDDLE_SYM', text: '@left-middle'},
+    {name: 'LEFTBOTTOM_SYM', text: '@left-bottom'},
+    {name: 'RIGHTTOP_SYM', text: '@right-top'},
+    {name: 'RIGHTMIDDLE_SYM', text: '@right-middle'},
+    {name: 'RIGHTBOTTOM_SYM', text: '@right-bottom'},
+
+    /*
+     * The following token names are defined in CSS3 Media Queries: https://www.w3.org/TR/css3-mediaqueries/#syntax
+     */
+    {name: 'RESOLUTION', state: 'media'},
+
+    /*
+     * The following token names are not defined in any CSS specification but are used by the lexer.
+     */
+
+    // not a real token, but useful for stupid IE filters
+    {name: 'IE_FUNCTION'},
+
+    // part of CSS3 grammar but not the Flex code
+    {name: 'CHAR'},
+
+    // TODO: Needed?
+    // Not defined as tokens, but might as well be
+    {name: 'PIPE', text: '|'},
+    {name: 'SLASH', text: '/'},
+    {name: 'MINUS', text: '-'},
+    {name: 'STAR', text: '*'},
+
+    {name: 'LBRACE', text: '{', endChar: '}'},
+    {name: 'RBRACE', text: '}'},
+    {name: 'LBRACKET', text: '[', endChar: ']'},
+    {name: 'RBRACKET', text: ']'},
+    {name: 'EQUALS', text: '='},
+    {name: 'COLON', text: ':'},
+    {name: 'SEMICOLON', text: ';'},
+    {name: 'LPAREN', text: '(', endChar: ')'},
+    {name: 'RPAREN', text: ')'},
+    {name: 'DOT', text: '.'},
+
+    {name: 'USO_VAR', comment: true},
+    {name: 'CUSTOM_PROP'},
+  ];
+
+  {
+    Tokens.UNKNOWN = -1;
+    Tokens.unshift({name: 'EOF'});
+
+    const nameMap = [];
+    const typeMap = new Map();
+    for (let i = 0, len = Tokens.length; i < len; i++) {
+      nameMap.push(Tokens[i].name);
+      Tokens[Tokens[i].name] = i;
+      if (Tokens[i].text) {
+        if (Tokens[i].text instanceof Array) {
+          for (let j = 0; j < Tokens[i].text.length; j++) {
+            typeMap.set(Tokens[i].text[j], i);
+          }
+        } else {
+          typeMap.set(Tokens[i].text, i);
+        }
+      }
+    }
+
+    Tokens.name = function (tt) {
+      return nameMap[tt];
+    };
+
+    Tokens.type = function (c) {
+      return typeMap.get(c) || -1;
+    };
+  }
+
+  //endregion
+  //region lowerCase helper
+
+  const lowercaseCache = new Map();
+
+  function lower(text) {
+    if (typeof text !== 'string') text = String(text);
+    let result = lowercaseCache.get(text);
+    if (result) return result;
+    result = text.toLowerCase();
+    lowercaseCache.set(text, result);
+    return result;
+  }
+
+  //endregion
+  //region parserCache
+
+  /**
+   * Caches the results and reuses them on subsequent parsing of the same code
+   */
+  const parserCache = (() => {
+    const MAX_DURATION = 10 * 60e3;
+    const TRIM_DELAY = 10e3;
+
+    // all blocks since page load; key = text between block start and { inclusive
+    const data = new Map();
+    // nested block stack
+    const stack = [];
+    // performance.now() of the current parser
+    let generation = null;
+    // performance.now() of the first parser after reset or page load,
+    // used for weighted sorting in getBlock()
+    let generationBase = null;
+    // true on page load, first run is pure analysis
+    let firstRun = true;
+    let parser = null;
+    let stream = null;
+
+    return {
+      start,
+      addEvent,
+      findBlock,
+      startBlock,
+      adjustBlockStart,
+      endBlock,
+      cancelBlock: () => stack.pop(),
+      feedback,
+    };
+
+    /**
+     * Enables caching on the provided parser
+     * @param {Parser} newParser - use a falsy value to disable
+     */
+    function start(newParser) {
+      parser = newParser;
+      if (!parser) return;
+      if (firstRun) firstRun = false;
+      stream = parser._tokenStream;
+      generation = generationBase = performance.now();
+      trim();
+    }
+
+    /**
+     * Adds the event into a matching nested open block which is currently being processed by the parser.
+     * @param {{offset, ...}} event - the event's `offset` property is used to determine the matching block
+     */
+    function addEvent(event) {
+      if (!parser) return;
+      for (let i = stack.length; --i >= 0;) {
+        const {offset, endOffset, events} = stack[i];
+        if (event.offset >= offset && (!endOffset || event.offset <= endOffset)) {
+          events.push(event);
+          return;
+        }
+      }
+    }
+
+    /**
+     * Starts a nested block so it can accumulate subsequent events
+     * @param {(Token|SyntaxUnit)} [start = TokenStream::LT(1)]
+     */
+    function startBlock(start = getToken()) {
+      if (!parser) return;
+      stack.push({
+        text: '',
+        events: [],
+        generation: generation,
+        startLine: start.startLine || start.line,
+        startCol: start.startCol || start.col,
+        offset: start.offset,
+        endLine: undefined,
+        endCol: undefined,
+        endOffset: undefined,
+      });
+    }
+
+    /**
+     * Adjusts the start position of an already started block
+     * @param {(Token|SyntaxUnit)} [start = TokenStream::LT(1)]
+     */
+    function adjustBlockStart(start = getToken()) {
+      if (!parser) return;
+      const block = stack[stack.length - 1];
+      block.startLine = start.startLine || start.line;
+      block.startCol = start.startCol || start.col;
+      block.offset = start.offset;
+    }
+
+    /**
+     * Closes the last opened block at the specified position and stores it in the cache
+     * @param {(Token|SyntaxUnit)} [token = TokenStream::LT(1)]
+     */
+    function endBlock(end = getToken()) {
+      if (!parser) return;
+      const block = stack.pop();
+      block.endLine = end.startLine || end.line;
+      block.endCol = (end.startCol || end.col) + end.value.length;
+      block.endOffset = end.offset + end.value.length;
+
+      const input = stream._reader._input;
+      const key = input.slice(block.offset, input.indexOf('{', block.offset) + 1);
+      block.text = input.slice(block.offset, block.endOffset);
+
+      let blocks = data.get(key);
+      if (!blocks) data.set(key, (blocks = []));
+      blocks.push(block);
+    }
+
+    /**
+     * Tries to find a cached block that matches the input text at specified token's position.
+     * The nearest matching block is used to advance the parser's stream and reader.
+     * @param {(Token|SyntaxUnit)} [token = TokenStream::LT(1)]
+     */
+    function findBlock(token = getToken()) {
+      if (!parser || firstRun || !token) return;
+
+      const reader = stream._reader;
+      const input = reader._input;
+      let start = token.offset;
+      if (isWhitespace(input[start])) {
+        const rx = /\s*/y;
+        rx.lastIndex = start;
+        rx.exec(input);
+        start = rx.lastIndex;
+      }
+      const key = input.slice(start, input.indexOf('{', start) + 1);
+      const blocks = data.get(key);
+      if (!blocks) return;
+
+      const block = getBlock(blocks, input, start, key);
+      if (!block) return;
+
+      reader.readCount(start - reader._cursor);
+      shiftBlock(reader, start, block);
+      shiftStream(reader, block);
+      parser._ws();
+      return true;
+    }
+
+    /**
+     * Removes old entries from the cache.
+     * 'Old' means older than MAX_DURATION or half the blocks from the previous generation(s).
+     * @param {Boolean} [immediately] - set internally when debounced by TRIM_DELAY
+     */
+    function trim(immediately) {
+      if (!immediately) {
+        clearTimeout(trim.timer);
+        trim.timer = setTimeout(trim, TRIM_DELAY, true);
+        return;
+      }
+      const cutoff = performance.now() - MAX_DURATION;
+      for (const [key, blocks] of data.entries()) {
+        const halfLen = blocks.length >> 1;
+        const newBlocks = blocks
+          .sort((a, b) => a.time - b.time)
+          .filter((block, i) => block.generation > cutoff ||
+                                block.generation !== generation && i < halfLen);
+        if (!newBlocks.length) {
+          data.delete(key);
+        } else if (newBlocks.length !== blocks.length) {
+          data.set(key, newBlocks);
+        }
+      }
+    }
+
+    /**
+     * Uses the provided CSSLint report to decide which blocks should keep their events.
+     * Blocks that didn't cause any messages in CSSLint's rules report are stripped of their events.
+     * @param {{line, col, ...}[]} messages
+     * @todo retain stats and rollups in the report
+     */
+    function feedback({messages}) {
+      messages = new Set(messages);
+      for (const blocks of data.values()) {
+        for (const block of blocks) {
+          if (!block.events.length) continue;
+          if (block.generation !== generation) continue;
+          const {
+            startLine: L1,
+            startCol: C1,
+            endLine: L2,
+            endCol: C2,
+          } = block;
+          let isClean = true;
+          for (const msg of messages) {
+            const {line, col} = msg;
+            if (L1 === L2 && line === L1 && C1 <= col && col <= C2 ||
+                line === L1 && col >= C1 ||
+                line === L2 && col <= C2 ||
+                line > L1 && line < L2) {
+              messages.delete(msg);
+              isClean = false;
+            }
+          }
+          if (isClean) block.events.length = 0;
+        }
+      }
+    }
+
+    // gets the matching block
+    function getBlock(blocks, input, start, key) {
+      // extracted to prevent V8 deopt
+      const keyLast = Math.max(key.length - 1);
+      const check1 = input[start];
+      const check2 = input[start + keyLast];
+      const generationSpan = performance.now() - generationBase;
+      blocks = blocks
+        .filter(({text, offset, endOffset}) =>
+          text[0] === check1 &&
+          text[keyLast] === check2 &&
+          text[text.length - 1] === input[start + text.length - 1] &&
+          text.startsWith(key) &&
+          text === input.substr(start, endOffset - offset))
+        .sort((a, b) =>
+          // newest and closest will be the first element
+          (a.generation - b.generation) / generationSpan +
+          (Math.abs(a.offset - start) - Math.abs(b.offset - start)) / input.length);
+      // identical blocks may produce different reports in CSSLint
+      // so we need to either hijack an older generation block or make a clone
+      const block = blocks.find(b => b.generation !== generation);
+      return block || deepCopy(blocks[0]);
+    }
+
+    // Shifts positions of the block and its events, also fires the events
+    function shiftBlock(reader, start, block) {
+      // extracted to prevent V8 deopt
+      const deltaLines = reader._line - block.startLine;
+      const deltaCols = block.startCol === 1 && reader._col === 1 ? 0 : reader._col - block.startCol;
+      const deltaOffs = reader._cursor - block.offset;
+      const hasDelta = deltaLines || deltaCols || deltaOffs;
+      const shifted = new Set();
+      for (const e of block.events) {
+        if (hasDelta) {
+          applyDelta(e, shifted, block.startLine, deltaLines, deltaCols, deltaOffs);
+        }
+        parser.fire(e, false);
+      }
+      block.generation = generation;
+      block.endCol += block.endLine === block.startLine ? deltaCols : 0;
+      block.endLine += deltaLines;
+      block.endOffset = reader._cursor + block.text.length;
+      block.startLine += deltaLines;
+      block.startCol += deltaCols;
+      block.offset = reader._cursor;
+    }
+
+    function shiftStream(reader, block) {
+      reader._line = block.endLine;
+      reader._col = block.endCol;
+      reader._cursor = block.endOffset;
+
+      stream._lt.length = 0;
+      stream._ltIndexCache.length = 0;
+      stream._ltIndex = 0;
+      stream._token = undefined;
+    }
+
+    // Recursively applies the delta to the event and all its nested parts
+    function applyDelta(obj, seen, startLine, lines, cols, offs) {
+      if (seen.has(obj)) return;
+      seen.add(obj);
+      if (Array.isArray(obj)) {
+        for (const item of obj) {
+          if ((typeof item === 'object' || Array.isArray(item)) && item) {
+            applyDelta(item, seen, startLine, lines, cols, offs);
+          }
+        }
+        return;
+      }
+      // applyDelta may get surpisingly slow on complex objects so we're using an array
+      // because in js an array lookup is much faster than a property lookup
+      const keys = Object.keys(obj);
+      if (cols !== 0) {
+        if (keys.includes('startCol') && obj.startLine === startLine) obj.col += cols;
+        if (keys.includes('endCol') && obj.endLine === startLine) obj.endCol += cols;
+        if (keys.includes('col') && obj.line === startLine) obj.col += cols;
+      }
+      if (lines !== 0) {
+        if (keys.includes('line')) obj.line += lines;
+        if (keys.includes('endLine')) obj.endLine += lines;
+        if (keys.includes('startLine')) obj.startLine += lines;
+      }
+      if (offs !== 0 && keys.includes('offset')) obj.offset += offs;
+      for (const k of keys) {
+        if (k !== 'col' && k !== 'startCol' && k !== 'endCol' &&
+            k !== 'line' && k !== 'startLine' && k !== 'endLine' &&
+            k !== 'offset') {
+          const v = obj[k];
+          if (v && typeof v === 'object') {
+            applyDelta(v, seen, startLine, lines, cols, offs);
+          }
+        }
+      }
+    }
+
+    // returns TokenStream::LT(1) or null
+    function getToken() {
+      return parser ?
+        stream._lt[stream._ltIndex] || stream._token :
+        null;
+    }
+
+    function deepCopy(obj) {
+      if (!obj || typeof obj !== 'object') return obj;
+      if (Array.isArray(obj)) {
+        return obj.map(v => !v || typeof v !== 'object' ? v : deepCopy(v));
+      }
+      const copy = {};
+      const hasOwnProperty = Object.prototype.hasOwnProperty;
+      for (const k in obj) {
+        if (!hasOwnProperty.call(obj, k)) continue;
+        const v = obj[k];
+        copy[k] = !v || typeof v !== 'object' ? v : deepCopy(v);
+      }
+      return copy;
+    }
+  })();
+
+  //endregion
+  //region EventTarget
+
+  class EventTarget {
+
+    constructor() {
+      this._listeners = new Map();
+    }
+
+    addListener(type, fn) {
+      let listeners = this._listeners.get(type);
+      if (!listeners) this._listeners.set(type, (listeners = new Set()));
+      listeners.add(fn);
+    }
+
+    fire(event) {
+      if (typeof event === 'string') {
+        event = {type: event};
+      }
+      if (typeof event.target !== 'undefined') {
+        event.target = this;
+      }
+
+      if (typeof event.type === 'undefined') {
+        throw new Error("Event object missing 'type' property.");
+      }
+
+      const listeners = this._listeners.get(event.type);
+      if (!listeners) return;
+      for (const fn of listeners.values()) {
+        fn.call(this, event);
+      }
+    }
+
+    removeListener(type, fn) {
+      const listeners = this._listeners.get(type);
+      if (listeners) listeners.delete(fn);
+    }
+  }
+
+  //endregion
+  //region SyntaxUnit
+
+  class SyntaxUnit {
+
+    constructor(text, pos, type) {
+      this.col = pos.col || pos.startCol;
+      this.line = pos.line || pos.startLine;
+      this.offset = pos.offset;
+      this.text = text;
+      this.type = type;
+    }
+
+    valueOf() {
+      return this.text;
+    }
+
+    toString() {
+      return this.text;
+    }
+
+    static fromToken(token) {
+      return new SyntaxUnit(token.value, token);
+    }
+  }
+
+  //endregion
+  //region PropertyName
+
+  class PropertyName extends SyntaxUnit {
+
+    constructor(text, hack, pos) {
+      super(text, pos, TYPES.PROPERTY_NAME_TYPE);
+      /**
+       * The type of IE hack applied ("*", "_", or null).
+       * @type String
+       * @property hack
+       */
+      this.hack = hack;
+    }
+
+    toString() {
+      return (this.hack || '') + this.text;
+    }
+  }
+
+  //endregion
+  //region PropertyValue
+
+  class PropertyValue extends SyntaxUnit {
+    /**
+     * Represents a single part of a CSS property value, meaning that it represents
+     * just everything single part between ":" and ";". If there are multiple values
+     * separated by commas, this type represents just one of the values.
+     * @param {String[]} parts An array of value parts making up this value.
+     */
+    constructor(parts, pos) {
+      super(parts.join(' '), pos, TYPES.PROPERTY_VALUE_TYPE);
+      this.parts = parts;
+    }
+  }
+
+  //endregion
+  //region PropertyValuePart
+
+  const tokenConverter = new Map();
+
+  class PropertyValuePart extends SyntaxUnit {
+    /**
+     * Represents a single part of a CSS property value, meaning that it represents
+     * just one part of the data between ":" and ";".
+     */
+    constructor(token) {
+      const {value, type} = token;
+      super(value, token, TYPES.PROPERTY_VALUE_PART_TYPE);
+
+      this.type = 'unknown';
+      this.tokenType = type;
+      // There can be ambiguity with escape sequences in identifiers, as
+      // well as with "color" parts which are also "identifiers", so record
+      // an explicit hint when the token generating this PropertyValuePart
+      // was an identifier.
+      this.wasIdent = type === Tokens.IDENT;
+
+      const cvt = tokenConverter.get(type);
+      if (cvt && cvt(this, token) !== false) return;
+
+      if (value === ',' || value === '/') {
+        this.type = 'operator';
+        this.value = value;
+        return;
+      }
+    }
+
+    static parseString(str) {
+      const replacer = (match, esc) => {
+        if (isNewLine(esc)) return '';
+        const m = /^[0-9a-f]{1,6}/i.exec(esc);
+        return m ? String.fromCodePoint(parseInt(m[0], 16)) : esc;
+      };
+      // Strip surrounding single/double quotes
+      str = str.slice(1, -1);
+      return str.replace(/\\(\r\n|[^\r0-9a-f]|[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?)/ig, replacer);
+    }
+
+    static serializeString(value) {
+      const replacer = c => {
+        if (c === '"') return '\\' + c;
+        // We only escape non-surrogate chars, so using charCodeAt is harmless here.
+        const cp = String.codePointAt ? c.codePointAt(0) : c.charCodeAt(0);
+        return '\\' + cp.toString(16) + ' ';
+      };
+      return '"' + value.replace(/["\r\n\f]/g, replacer) + '"';
+    }
+  }
+
+  [
+    ...(fn => [
+      Tokens.LENGTH,
+      Tokens.ANGLE,
+      Tokens.TIME,
+      Tokens.FREQ,
+      Tokens.DIMENSION,
+      Tokens.PERCENTAGE,
+      Tokens.NUMBER,
+    ].map(tt => [tt, fn]))((self, {number, units, unitsType}) => {
+      self.value = number;
+      self.units = units;
+      self.type = unitsType === 'number' && !self.text.includes('.') ? 'integer' : unitsType;
+    }),
+
+    [Tokens.HASH, (self, {value}) => {
+
+      self.type = 'color';
+      if (value.length <= 5) {
+        let n = parseInt(value.slice(1), 16);
+        if (value.length === 5) {
+          self.alpha = (n & 15) << 4 + (n & 15);
+          n >>= 4;
+        }
+        self.red = (n >> 8 & 15) << 4 + (n >> 8 & 15);
+        self.green = (n >> 4 & 15) << 4 + (n >> 4 & 15);
+        self.blue = (n & 15) << 4 + (n & 15);
+      } else {
+        const n = parseInt(value.substr(1, 6), 16);
+        self.red = n >> 16;
+        self.green = (n >> 8) & 255;
+        self.blue = n & 255;
+        if (value.length === 9) {
+          self.alpha = parseInt(value.substr(7, 2), 16);
+        }
+      }
+
+    }],
+    [Tokens.FUNCTION, (self, {name, expr}) => {
+
+      self.name = name;
+      self.expr = expr;
+      const parts = expr && expr.parts;
+      switch (parts && lower(name)) {
+        case 'rgb':
+        case 'rgba': {
+          const [r, g, b, a] = parts.map(p => !/[,/]/.test(p)).map(parseFloat);
+          const pct = parts[0].tokenType === Tokens.PERCENTAGE ? 2.55 : 1;
+          self.type = 'color';
+          self.red = r * pct;
+          self.green = g * pct;
+          self.blue = b * pct;
+          if (!isNaN(a)) self.alpha = a * (/%/.test(parts[parts.length - 1]) ? 2.55 / 100 : 1);
+          return;
+        }
+        case 'hsl':
+        case 'hsla': {
+          const [h, s, l, a] = parts.map(p => !/[,/]/.test(p)).map(parseFloat);
+          self.type = 'color';
+          self.hue = h;
+          self.hueUnit = parts[0].units;
+          self.saturation = s;
+          self.lightness = l;
+          if (!isNaN(a)) self.alpha = a * (/%/.test(parts[parts.length - 1]) ? 2.55 / 100 : 1);
+          return;
+        }
+        default:
+          self.type = 'function';
+      }
+
+    }],
+    [Tokens.URI, (self, {name, uri}) => {
+
+      self.type = 'uri';
+      self.name = name;
+      self.uri = uri;
+
+    }],
+    [Tokens.STRING, self => {
+
+      const text = self.text;
+      if (text[0] === '"' &&
+          /^"([^\n\r\f\\"]|\\\r\n|\\[^\r0-9a-f]|\\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?)*"/i.test(text)) {
+        self.type = 'string';
+        self.value = PropertyValuePart.parseString(text);
+        return;
+      }
+      if (text[0] === "'" &&
+          /^'([^\n\r\f\\']|\\\r\n|\\[^\r0-9a-f]|\\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?)*'/i.test(text)) {
+        self.type = 'string';
+        self.value = PropertyValuePart.parseString(text);
+      }
+
+    }],
+    [Tokens.IDENT, self => {
+
+      const text = self.text;
+      let namedColor;
+      if (!text.includes('-') && (namedColor = Colors[lower(text)])) {
+        tokenConverter.get(Tokens.HASH)(self, {value: namedColor});
+      } else {
+        self.type = 'identifier';
+        self.value = text;
+      }
+
+    }],
+    [Tokens.CUSTOM_PROP, self => {
+
+      self.type = 'custom-property';
+      self.value = self.text;
+
+    }],
+  ].forEach(([tt, fn]) => tokenConverter.set(tt, fn));
+
+  //endregion
+  //region SelectorPart
+
+  class SelectorPart extends SyntaxUnit {
+    /**
+     * Represents a single part of a selector string, meaning a single set of
+     * element name and modifiers. This does not include combinators such as
+     * spaces, +, >, etc.
+     * @param {String} elementName The element name in the selector or null
+     *      if there is no element name.
+     * @param {Array} modifiers Array of individual modifiers for the element.
+     *      The parts that come after the element name, such as class names, IDs, pseudo classes/elements, etc.
+     *      May be empty if there are none.
+     */
+    constructor(elementName, modifiers, text, pos) {
+      super(text, pos, TYPES.SELECTOR_PART_TYPE);
+      this.elementName = elementName;
+      this.modifiers = modifiers;
+    }
+  }
+
+  //endregion
+  //region Specificity
+
+  class Specificity {
+    /**
+     * Represents a selector's specificity.
+     * @namespace parserlib.css
+     * @class Specificity
+     * @constructor
+     * @param {int} a Should be 1 for inline styles, zero for stylesheet styles
+     * @param {int} b Number of ID selectors
+     * @param {int} c Number of classes and pseudo classes
+     * @param {int} d Number of element names and pseudo elements
+     */
+    constructor(a, b, c, d) {
+      this.a = a;
+      this.b = b;
+      this.c = c;
+      this.d = d;
+      this.constructor = Specificity;
+    }
+
+    /**
+     * Compare this specificity to another.
+     * @param {Specificity} other The other specificity to compare to.
+     * @return {int} -1 if the other specificity is larger, 1 if smaller, 0 if equal.
+     * @method compare
+     */
+    compare(other) {
+      const comps = ['a', 'b', 'c', 'd'];
+
+      for (let i = 0, len = comps.length; i < len; i++) {
+        if (this[comps[i]] < other[comps[i]]) {
+          return -1;
+        } else if (this[comps[i]] > other[comps[i]]) {
+          return 1;
+        }
+      }
+
+      return 0;
+    }
+
+    /**
+     * Creates a numeric value for the specificity.
+     * @return {int} The numeric value for the specificity.
+     * @method valueOf
+     */
+    valueOf() {
+      return (this.a * 1000) + (this.b * 100) + (this.c * 10) + this.d;
+    }
+
+    /**
+     * Returns a string representation for specificity.
+     * @return {String} The string representation of specificity.
+     * @method toString
+     */
+    toString() {
+      return this.a + ',' + this.b + ',' + this.c + ',' + this.d;
+    }
+
+    /**
+     * Calculates the specificity of the given selector.
+     * @param {parserlib.css.Selector} The selector to calculate specificity for.
+     * @return {parserlib.css.Specificity} The specificity of the selector.
+     * @static
+     * @method calculate
+     */
+    static calculate(selector) {
+
+      let i, len, part;
+      let b = 0;
+      let c = 0;
+      let d = 0;
+
+      function updateValues(part) {
+
+        let i, j, len, num, modifier;
+        const elementName = part.elementName ? part.elementName.text : '';
+
+        if (elementName && elementName.charAt(elementName.length - 1) !== '*') {
+          d++;
+        }
+
+        for (i = 0, len = part.modifiers.length; i < len; i++) {
+          modifier = part.modifiers[i];
+          switch (modifier.type) {
+            case 'class':
+            case 'attribute':
+              c++;
+              break;
+
+            case 'id':
+              b++;
+              break;
+
+            case 'pseudo':
+              if (isPseudoElement(modifier.text)) {
+                d++;
+              } else {
+                c++;
+              }
+              break;
+
+            case 'not':
+              for (j = 0, num = modifier.args.length; j < num; j++) {
+                updateValues(modifier.args[j]);
+              }
+          }
+        }
+      }
+
+      for (i = 0, len = selector.parts.length; i < len; i++) {
+        part = selector.parts[i];
+
+        if (part instanceof SelectorPart) {
+          updateValues(part);
+        }
+      }
+
+      return new Specificity(0, b, c, d);
+    }
+  }
+
+  //endregion
+  //region SelectorSubPart
+
+  class SelectorSubPart extends SyntaxUnit {
+    /**
+     * Represents a selector modifier string, meaning a class name, element name,
+     * element ID, pseudo rule, etc.
+     */
+    constructor(text, type, pos) {
+      super(text, pos, TYPES.SELECTOR_SUB_PART_TYPE);
+      this.type = type;
+      // Some subparts have arguments
+      this.args = [];
+    }
+  }
+
+  //endregion
+  //region Selector
+
+  class Selector extends SyntaxUnit {
+    /**
+     * Represents an entire single selector, including all parts but not
+     * including multiple selectors (those separated by commas).
+     * @param {Array} parts Array of selectors parts making up this selector.
+     */
+    constructor(parts, pos) {
+      super(parts.join(' '), pos, TYPES.SELECTOR_TYPE);
+      this.parts = parts;
+      this.specificity = Specificity.calculate(this);
+    }
+  }
+
+  //endregion
+  //region SyntaxError
+
+  class SyntaxError extends Error {
+    constructor(message, pos) {
+      super();
+      this.name = this.constructor.name;
+      this.col = pos.col || pos.startCol;
+      this.line = pos.line || pos.startLine;
+      this.message = message;
+    }
+  }
+
+  //endregion
+  //region ValidationError
+
+  class ValidationError extends Error {
+    constructor(message, pos) {
+      super();
+      this.col = pos.col || pos.startCol;
+      this.line = pos.line || pos.startLine;
+      this.message = message;
+    }
+  }
+
+  //endregion
+  //region Combinator
+
+  class Combinator extends SyntaxUnit {
+    /**
+     * Represents a selector combinator (whitespace, +, >).
+     */
+    constructor(token) {
+      const {value} = token;
+      super(value, token, TYPES.COMBINATOR_TYPE);
+      this.type =
+        value === '>' ? 'child' :
+        value === '+' ? 'adjacent-sibling' :
+        value === '~' ? 'sibling' :
+        !value.trim() ? 'descendant' :
+          'unknown';
+    }
+  }
+
+  //endregion
+  //region StringReader
+
+  class StringReader {
+
+    constructor(text) {
+      this._input = text.replace(/\r\n?/g, '\n');
+      this._line = 1;
+      this._col = 1;
+      this._cursor = 0;
+    }
+
+    eof() {
+      return this._cursor >= this._input.length;
+    }
+
+    peek(count = 1) {
+      return this._input[this._cursor + count - 1] || null;
+    }
+
+    read() {
+      const c = this._input[this._cursor];
+      if (!c) return null;
+      if (c === '\n') {
+        this._line++;
+        this._col = 1;
+      } else {
+        this._col++;
+      }
+      this._cursor++;
+      return c;
+    }
+
+    mark() {
+      this._bookmark = {
+        cursor: this._cursor,
+        line: this._line,
+        col: this._col,
+      };
+    }
+
+    reset() {
+      if (this._bookmark) {
+        this._cursor = this._bookmark.cursor;
+        this._line = this._bookmark.line;
+        this._col = this._bookmark.col;
+        delete this._bookmark;
+      }
+    }
+
+    /**
+     * Reads up to and including the given string.
+     * @param {String} pattern The string to read.
+     * @return {String} The string when it is found.
+     * @throws Error when the string pattern is not found.
+     */
+    readTo(pattern) {
+      const i = this._input.indexOf(pattern, this._cursor);
+      if (i < 0) throw new Error(`Expected ${pattern}' at line ${this._line}, col ${this._col}.`);
+      return this.readCount(i - this._cursor + pattern.length);
+    }
+
+    /**
+     * Reads characters that match either text or a regular expression and
+     * returns those characters. If a match is found, the row and column
+     * are adjusted; if no match is found, the reader's state is unchanged.
+     * reading or false to stop.
+     * @param {String|RegExp} matcher If a string, then the literal string
+     *      value is searched for. If a regular expression, then any string
+     *      matching the pattern is search for.
+     * @return {String} The string made up of all characters that matched or
+     *      null if there was no match.
+     */
+    readMatch(matcher) {
+      if (matcher.sticky) {
+        matcher.lastIndex = this._cursor;
+        return matcher.test(this._input) ?
+          this.readCount(RegExp.lastMatch.length) :
+          null;
+      }
+      if (typeof matcher === 'string') {
+        if (this._input[this._cursor] === matcher[0] &&
+            this._input.substr(this._cursor, matcher.length) === matcher) {
+          return this.readCount(matcher.length);
+        }
+      } else if (matcher instanceof RegExp) {
+        if (matcher.test(this._input.substr(this._cursor))) {
+          return this.readCount(RegExp.lastMatch.length);
+        }
+      }
+      return null;
+    }
+
+    /**
+     * Reads a given number of characters. If the end of the input is reached,
+     * it reads only the remaining characters and does not throw an error.
+     * @param {int} count The number of characters to read.
+     * @return {String} The string made up the read characters.
+     */
+    readCount(count) {
+      const len = this._input.length;
+      if (this._cursor >= len) return null;
+      if (!count) return '';
+
+      const text = this._input.substr(this._cursor, count);
+      this._cursor = Math.min(this._cursor + count, len);
+
+      let prev = -1;
+      for (let i = 0; (i = text.indexOf('\n', i)) >= 0; prev = i, i++) this._line++;
+      this._col = prev < 0 ? this._col + count : count - prev;
+
+      return text;
+    }
+  }
+
+  //endregion
+  //region Matcher
+
+  const cachedMatcher = new Map();
+
+  class Matcher {
+    /**
+     * This class implements a combinator library for matcher functions.
+     * The combinators are described at:
+     * https://developer.mozilla.org/en-US/docs/Web/CSS/Value_definition_syntax#Component_value_combinators
+     */
+    constructor(matchFunc, toString) {
+      this.matchFunc = matchFunc;
+      this.toString = typeof toString === 'function' ? toString : () => toString;
+    }
+
+    static parse(str) {
+      let m = cachedMatcher.get(str);
+      if (m) return m;
+      m = Matcher.doParse(str);
+      cachedMatcher.set(str, m);
+      return m;
+    }
+
+    /** Simple recursive-descent grammar to build matchers from strings. */
+    static doParse(str) {
+      const reader = new StringReader(str);
+      function eat(matcher) {
+        const result = reader.readMatch(matcher);
+        if (result === null) {
+          throw new SyntaxError('Expected ' + matcher, reader._line, reader._col);
+        }
+        return result;
+      }
+      function expr() {
+        // expr = oror (" | " oror)*
+        const m = [oror()];
+        while (reader.readMatch(' | ')) {
+          m.push(oror());
+        }
+        return m.length === 1 ? m[0] : Matcher.alt.apply(Matcher, m);
+      }
+      function oror() {
+        // oror = andand ( " || " andand)*
+        const m = [andand()];
+        while (reader.readMatch(' || ')) {
+          m.push(andand());
+        }
+        return m.length === 1 ? m[0] : Matcher.oror.apply(Matcher, m);
+      }
+      function andand() {
+        // andand = seq ( " && " seq)*
+        const m = [seq()];
+        while (reader.readMatch(' && ')) {
+          m.push(seq());
+        }
+        return m.length === 1 ? m[0] : Matcher.andand.apply(Matcher, m);
+      }
+      function seq() {
+        // seq = mod ( " " mod)*
+        const m = [mod()];
+        while (reader.readMatch(/\s(?![&|\]])/y)) {
+          m.push(mod());
+        }
+        return m.length === 1 ? m[0] : Matcher.seq.apply(Matcher, m);
+      }
+      function mod() {
+        // mod = term ( "?" | "*" | "+" | "#" | "{<num>,<num>}" )?
+        const m = term();
+        reader.mark();
+        let hash;
+        switch (reader.read()) {
+          case '?': return m.question();
+          case '*': return m.star();
+          case '+': return m.plus();
+          case '#':
+            if (reader.peek() !== '{') return m.hash();
+            reader.read();
+            hash = '#';
+            // fallthrough
+          case '{': {
+            const min = eat(/\s*\d+\s*/y).trim();
+            const c = eat(/[,}]/y);
+            const max = c === ',' ? eat(/\s*\d+\s*}/y).slice(0, -1).trim() : min;
+            return m.braces(Number(min), Number(max), hash, hash && Matcher.cast(','));
+          }
+          default:
+            reader.reset();
+        }
+        return m;
+      }
+      function term() {
+        // term = <nt> | literal | "[ " expression " ]"
+        if (reader.readMatch('[ ')) {
+          const m = expr();
+          eat(' ]');
+          return m;
+        }
+        return Matcher.fromType(eat(/[^\s?*+#{]+/y));
+      }
+      const result = expr();
+      if (!reader.eof()) {
+        throw new SyntaxError('Expected end of string', reader._line, reader._col);
+      }
+      return result;
+    }
+
+    static cast(m) {
+      return m instanceof Matcher ? m : Matcher.parse(m);
+    }
+
+    // Matcher for a single type.
+    static fromType(type) {
+      let m = cachedMatcher.get(type);
+      if (m) return m;
+      m = new Matcher(expr => expr.hasNext() && ValidationTypes.isType(expr, type), type);
+      cachedMatcher.set(type, m);
+      return m;
+    }
+
+    // Matcher for one or more juxtaposed words, which all must occur, in the given order.
+    static seq(...args) {
+      const ms = args.map(Matcher.cast);
+      if (ms.length === 1) return ms[0];
+      return new Matcher(
+        expression => ms.every(m => m.match(expression)),
+        prec => {
+          const p = Matcher.prec.SEQ;
+          const s = ms.map(m => m.toString(p)).join(' ');
+          return prec > p ? `[ ${s} ]` : s;
+        });
+    }
+
+    // Matcher for one or more alternatives, where exactly one must occur.
+    static alt(...args) {
+      const ms = args.map(Matcher.cast);
+      if (ms.length === 1) return ms[0];
+      return new Matcher(
+        expression => ms.some(m => m.match(expression)),
+        prec => {
+          const p = Matcher.prec.ALT;
+          const s = ms.map(m => m.toString(p)).join(' | ');
+          return prec > p ? `[ ${s} ]` : s;
+        });
+    }
+
+    /**
+     * Matcher for two or more options: double bar (||) and double ampersand (&&) operators,
+     * as well as variants of && where some of the alternatives are optional.
+     * This will backtrack through even successful matches to try to
+     * maximize the number of items matched.
+     */
+    static many(required, ...args) {
+      const ms = [];
+      for (const arg of args) {
+        if (arg.expand) {
+          ms.push(...ValidationTypes.complex[arg.expand].options);
+        } else {
+          ms.push(Matcher.cast(arg));
+        }
+      }
+
+      if (required === true) required = new Array(ms.length).fill(true);
+
+      const result = new Matcher(expression => {
+        const seen = [];
+        let max = 0;
+        let pass = 0;
+        // If couldn't get a complete match, retrace our steps to make the
+        // match with the maximum # of required elements.
+        if (!tryMatch(0)) {
+          pass++;
+          tryMatch(0);
+        }
+        if (required === false) {
+          return max > 0;
+        }
+        // Use finer-grained specification of which matchers are required.
+        for (let i = 0; i < ms.length; i++) {
+          if (required[i] && !seen[i]) {
+            return false;
+          }
+        }
+        return true;
+
+        function tryMatch(matchCount) {
+          for (let i = 0; i < ms.length; i++) {
+            if (seen[i]) continue;
+            expression.mark();
+            if (!ms[i].match(expression)) {
+              expression.drop();
+              continue;
+            }
+            seen[i] = true;
+            // Increase matchCount if this was a required element
+            // (or if all the elements are optional)
+            if (tryMatch(matchCount + (required === false || required[i] ? 1 : 0))) {
+              expression.drop();
+              return true;
+            }
+            // Backtrack: try *not* matching using this rule, and
+            // let's see if it leads to a better overall match.
+            expression.restore();
+            seen[i] = false;
+          }
+          if (pass === 0) {
+            max = Math.max(matchCount, max);
+            return matchCount === ms.length;
+          } else {
+            return matchCount === max;
+          }
+        }
+
+      }, prec => {
+        const p = required === false ? Matcher.prec.OROR : Matcher.prec.ANDAND;
+        const s = ms.map((m, i) => {
+          if (required !== false && !required[i]) {
+            return m.toString(Matcher.prec.MOD) + '?';
+          }
+          return m.toString(p);
+        }).join(required === false ? ' || ' : ' && ');
+        return prec > p ? `[ ${s} ]` : s;
+      });
+
+      result.options = ms;
+      return result;
+    }
+
+    /**
+     * Create a matcher for two or more options, where all options are
+     * mandatory but they may appear in any order.
+     */
+    static andand(...args) {
+      return Matcher.many(true, ...args);
+    }
+
+    /**
+     * Create a matcher for two or more options, where options are
+     * optional and may appear in any order, but at least one must be
+     * present.
+     */
+    static oror(...args) {
+      return Matcher.many(false, ...args);
+    }
+
+    match(expression) {
+      // Save/restore marks to ensure that failed matches always restore
+      // the original location in the expression.
+      expression.mark();
+
+      const result = this.matchFunc(expression);
+      if (result) expression.drop();
+      else expression.restore();
+
+      return result;
+    }
+
+    // This returns a standalone function to do the matching.
+    func() {
+      return (...args) => this.match(...args);
+    }
+
+    // Basic combinators
+
+    then(m) {
+      return Matcher.seq(this, m);
+    }
+
+    or(m) {
+      return Matcher.alt(this, m);
+    }
+
+    andand(m) {
+      return Matcher.many(true, this, m);
+    }
+
+    oror(m) {
+      return Matcher.many(false, this, m);
+    }
+
+    // Component value multipliers
+    star() {
+      return this.braces(0, Infinity, '*');
+    }
+
+    plus() {
+      return this.braces(1, Infinity, '+');
+    }
+
+    question() {
+      return this.braces(0, 1, '?');
+    }
+
+    hash() {
+      return this.braces(1, Infinity, '#', Matcher.cast(','));
+    }
+
+    braces(min, max, marker, optSep) {
+      optSep = optSep && optSep.then(this);
+      marker = marker || '{' + min + (min === max ? '' : ',' + max) + '}';
+
+      const matchNext = !optSep
+        ? expression => this.match(expression)
+        : (expression, i) => (!i ? this : optSep).match(expression);
+
+      const matchFunc = expression => {
+        let i = 0;
+        while (i < max && matchNext(expression, i)) i++;
+        return i >= min;
+      };
+
+      return new Matcher(matchFunc, () => this.toString(Matcher.prec.MOD) + marker);
+    }
+  }
+
+  // Precedence table of combinators.
+  Matcher.prec = {
+    MOD: 5,
+    SEQ: 4,
+    ANDAND: 3,
+    OROR: 2,
+    ALT: 1,
+  };
+
+  //endregion
+  //region MediaFeature
+
+  class MediaFeature extends SyntaxUnit {
+    /**
+     * Represents a media feature, such as max-width:500.
+     * @param {SyntaxUnit} name The name of the feature.
+     * @param {SyntaxUnit} value The value of the feature or null if none.
+     */
+    constructor(name, value) {
+      const text = '(' + name + (value !== null ? ':' + value : '') + ')';
+      super(text, name, TYPES.MEDIA_FEATURE_TYPE);
+
+      this.name = name;
+      this.value = value;
+    }
+  }
+
+  //endregion
+  //region MediaQuery
+
+  class MediaQuery extends SyntaxUnit {
+    /**
+     * Represents an individual media query.
+     * @param {String} modifier The modifier "not" or "only" (or null).
+     * @param {String} mediaType The type of media (i.e., "print").
+     * @param {Array} parts Array of selectors parts making up this selector.
+     */
+    constructor(modifier, mediaType, features, pos) {
+      const text = (modifier ? modifier + ' ' : '') +
+                   (mediaType ? mediaType : '') +
+                   (mediaType && features.length > 0 ? ' and ' : '') +
+                   features.join(' and ');
+      super(text, pos, TYPES.MEDIA_QUERY_TYPE);
+      this.modifier = modifier;
+      this.mediaType = mediaType;
+      this.features = features;
+    }
+  }
+
+  //endregion
+  //region PropertyValueIterator
+
+  class PropertyValueIterator {
+    /**
+     * A utility class that allows for easy iteration over the various parts of a
+     * property value.
+     * @param {parserlib.css.PropertyValue} value The property value to iterate over.
+     */
+    constructor(value) {
+      this._i = 0;
+      this._parts = value.parts;
+      this._marks = [];
+      this.value = value;
+    }
+
+    hasNext() {
+      return this._i < this._parts.length;
+    }
+
+    peek(count) {
+      return this._parts[this._i + (count || 0)] || null;
+    }
+
+    next() {
+      return this._i < this._parts.length ? this._parts[this._i++] : null;
+    }
+
+    previous() {
+      return this._i > 0 ? this._parts[--this._i] : null;
+    }
+
+    mark() {
+      this._marks.push(this._i);
+    }
+
+    restore() {
+      if (this._marks.length) {
+        this._i = this._marks.pop();
+      }
+    }
+
+    drop() {
+      this._marks.pop();
+    }
+  }
+
+  //endregion
+  //region TokenStreamBase
+
+  // lookup table size for TokenStreamBase
+  const LT_SIZE = 5;
+
+  class TokenStreamBase {
+    /**
+     * Generic TokenStream providing base functionality.
+     */
+    constructor(input) {
+      this._reader = new StringReader(input ? input.toString() : '');
+      // Token object for the last consumed token.
+      this._token = null;
+      // Lookahead token buffer.
+      this._lt = [];
+      this._ltIndex = 0;
+      this._ltIndexCache = [];
+    }
+
+    /**
+     * Determines if the next token matches the given token type.
+     * If so, that token is consumed; if not, the token is placed
+     * back onto the token stream. You can pass in any number of
+     * token types and this will return true if any of the token
+     * types is found.
+     * @param {int|int[]} tokenTypes Either a single token type or an array of
+     *      token types that the next token might be. If an array is passed,
+     *      it's assumed that the token can be any of these.
+     * @return {Boolean} True if the token type matches, false if not.
+     */
+    match(tokenTypes) {
+      const isArray = Array.isArray(tokenTypes);
+      let tt;
+      do {
+        tt = this.get();
+        if (isArray ? tokenTypes.includes(tt) : tt === tokenTypes) {
+          return true;
+        }
+      } while (tt === Tokens.COMMENT && this.LA(0) !== 0);
+
+      // no match found, put the token back
+      this.unget();
+      return false;
+    }
+
+    /**
+     * Determines if the next token matches the given token type.
+     * If so, that token is consumed; if not, an error is thrown.
+     * @param {int|int[]} tokenTypes Either a single token type or an array of
+     *      token types that the next token should be. If an array is passed,
+     *      it's assumed that the token must be one of these.
+     * @return {void}
+     */
+    mustMatch(tokenTypes) {
+      if (!this.match(tokenTypes)) {
+        const {startLine: line, startCol: col, offset} = this.LT(1);
+        const info = Tokens[Array.isArray(tokenTypes) ? tokenTypes[0] : tokenTypes];
+        throw new SyntaxError(`Expected ${info.text || info.name} at line ${line}, col ${col}.`, {line, col, offset});
+      }
+    }
+
+    /**
+     * Keeps reading from the token stream until either one of the specified
+     * token types is found or until the end of the input is reached.
+     * @param {int|int[]} tokenTypes Either a single token type or an array of
+     *      token types that the next token should be. If an array is passed,
+     *      it's assumed that the token must be one of these.
+     * @return {void}
+     */
+    advance(tokenTypes) {
+      while (this.LA(0) !== 0 && !this.match(tokenTypes)) {
+        this.get();
+      }
+      return this.LA(0);
+    }
+
+    /**
+     * Consumes the next token from the token stream.
+     * @return {int} The token type of the token that was just consumed.
+     */
+    get() {
+      const cache = this._ltIndexCache;
+      const lt = this._lt;
+      let i = 0;
+
+      // check the lookahead buffer first
+      let len = lt.length;
+      let ltIndex = this._ltIndex;
+      if (len && ltIndex >= 0 && ltIndex < len) {
+        i++;
+        this._token = lt[ltIndex];
+        this._ltIndex = ++ltIndex;
+        if (ltIndex <= len) {
+          cache.push(i);
+          return this._token.type;
+        }
+      }
+
+      const token = this._getToken();
+      const type = token.type;
+      const isHidden = Tokens[type].hide;
+
+      if (type > -1 && !isHidden) {
+        // save for later
+        this._token = token;
+        lt.push(token);
+
+        // save space that will be moved (must be done before array is truncated)
+        cache.push(++len - ltIndex + i);
+
+        if (len > LT_SIZE) lt.shift();
+        if (cache.length > LT_SIZE) cache.shift();
+
+        // update lookahead index
+        this._ltIndex = lt.length;
+      }
+
+      // Skip to the next token if the token type is marked as hidden.
+      return isHidden ? this.get() : type;
+    }
+
+    /**
+     * Looks ahead a certain number of tokens and returns the token type at
+     * that position. This will throw an error if you lookahead past the
+     * end of input, past the size of the lookahead buffer, or back past
+     * the first token in the lookahead buffer.
+     * @param {int} The index of the token type to retrieve. 0 for the
+     *      current token, 1 for the next, -1 for the previous, etc.
+     * @return {int} The token type of the token in the given position.
+     */
+    LA(index) {
+      if (!index) return this._token.type;
+
+      if (index > 0) {
+        if (index > LT_SIZE) throw new Error('Too much lookahead.');
+        let total = index;
+        let tt;
+        while (total && total--) tt = this.get();
+        while (total++ < index) this.unget();
+        return tt;
+      }
+
+      if (index < 0) {
+        const token = this._lt[this._ltIndex + index];
+        if (!token) throw new Error('Too much lookbehind.');
+        return token.type;
+      }
+    }
+
+    /**
+     * Looks ahead a certain number of tokens and returns the token at
+     * that position. This will throw an error if you lookahead past the
+     * end of input, past the size of the lookahead buffer, or back past
+     * the first token in the lookahead buffer.
+     * @param {int} The index of the token type to retrieve. 0 for the
+     *      current token, 1 for the next, -1 for the previous, etc.
+     * @return {Object} The token of the token in the given position.
+     */
+    LT(index) {
+      // lookahead first to prime the token buffer
+      this.LA(index);
+      // now find the token, subtract one because _ltIndex is already at the next index
+      return this._lt[this._ltIndex + index - 1];
+    }
+
+    /**
+     * Returns the token type for the next token in the stream without
+     * consuming it.
+     * @return {int} The token type of the next token in the stream.
+     */
+    peek() {
+      return this.LA(1);
+    }
+
+    /**
+     * Returns the last consumed token to the token stream.
+     */
+    unget() {
+      if (this._ltIndexCache.length) {
+        this._ltIndex -= this._ltIndexCache.pop();
+        this._token = this._lt[this._ltIndex - 1];
+      } else {
+        throw new Error('Too much lookahead.');
+      }
+    }
+  }
+
+  //endregion
+  //region TokenStream
+
+  class TokenStream extends TokenStreamBase {
+
+    mustMatch(tokenTypes) {
+      this._skipUsoVar();
+      super.mustMatch(tokenTypes);
+    }
+
+    _skipUsoVar() {
+      const lt1 = this._lt[this._ltIndex] || this.LT(1);
+      if (lt1.type !== Tokens.USO_VAR) return;
+      while (this.match([Tokens.USO_VAR, Tokens.S])) { /*NOP*/ }
+    }
+
+    /**
+     * A token stream that produces CSS tokens.
+     */
+    _getToken() {
+      const reader = this._reader;
+      const pos = {
+        line: reader._line,
+        col: reader._col,
+        offset: reader._cursor,
+      };
+      const c = reader.read();
+      switch (c) {
+
+        case null:
+          return this.createToken(Tokens.EOF, null, pos);
+
+        /*
+         * Potential tokens:
+         * - S
+         */
+        case ' ':
+        case '\n':
+        case '\r':
+        case '\t':
+        case '\f':
+          return this.whitespaceToken(c, pos);
+
+        /*
+         * Potential tokens:
+         * - COMMENT
+         * - SLASH
+         * - CHAR
+         */
+        case '/':
+          return reader.peek() === '*' ?
+            this.commentToken(c, pos) :
+            this.charToken(c, pos);
+
+        /*
+         * Potential tokens:
+         * - DASHMATCH
+         * - INCLUDES
+         * - PREFIXMATCH
+         * - SUFFIXMATCH
+         * - SUBSTRINGMATCH
+         * - CHAR
+         */
+        case '|':
+        case '~':
+        case '^':
+        case '$':
+        case '*':
+          return reader.peek() === '=' ?
+            this.comparisonToken(c, pos) :
+            this.charToken(c, pos);
+
+        /*
+         * Potential tokens:
+         * - STRING
+         * - INVALID
+         */
+        case '"':
+        case "'":
+          return this.stringToken(c, pos);
+
+        /*
+         * Potential tokens:
+         * - HASH
+         * - CHAR
+         */
+        case '#':
+          return isNameChar(reader.peek()) ?
+            this.hashToken(c, pos) :
+            this.charToken(c, pos);
+
+        /*
+         * Potential tokens:
+         * - DOT
+         * - NUMBER
+         * - DIMENSION
+         * - PERCENTAGE
+         */
+        case '.':
+          return isDigit(reader.peek()) ?
+            this.numberToken(c, pos) :
+            this.charToken(c, pos);
+
+        /*
+         * Potential tokens:
+         * - CDC
+         * - MINUS
+         * - NUMBER
+         * - DIMENSION
+         * - PERCENTAGE
+         */
+        case '-':
+          // could be closing HTML-style comment or CSS variable
+          return (
+            reader.peek() === '-' ? (
+              /\w/.test(reader.peek(2)) ?
+                this.identOrFunctionToken(c, pos) :
+                this.htmlCommentEndToken(c, pos)
+            ) : (
+            isNameStart(reader.peek()) ?
+              this.identOrFunctionToken(c, pos) :
+              this.charToken(c, pos)
+            )
+          );
+
+        /*
+         * Potential tokens:
+         * - IMPORTANT_SYM
+         * - CHAR
+         */
+        case '!':
+          return this.importantToken(c, pos);
+
+        /*
+         * Any at-keyword or CHAR
+         */
+        case '@':
+          return this.atRuleToken(c, pos);
+
+        /*
+         * Potential tokens:
+         * - ANY
+         * - NOT
+         * - CHAR
+         */
+        case ':':
+          return this.notOrAnyToken(c, pos);
+
+        /*
+         * Potential tokens:
+         * - CDO
+         * - CHAR
+         */
+        case '<':
+          return this.htmlCommentStartToken(c, pos);
+
+        /*
+         * Potential tokens:
+         * - IDENT
+         * - CHAR
+         */
+        case '\\':
+          return /[^\r\n\f]/.test(reader.peek()) ?
+            this.identOrFunctionToken(this.readEscape(c), pos) :
+            this.charToken(c, pos);
+
+        /*
+         * Potential tokens:
+         * - UNICODE_RANGE
+         * - URL
+         * - CHAR
+         */
+        case 'U':
+        case 'u':
+          if (reader.peek() === '+') {
+            return this.unicodeRangeToken(c, pos);
+          }
+          // fallthrough
+      }
+
+      /*
+       * Potential tokens:
+       * - NUMBER
+       * - DIMENSION
+       * - LENGTH
+       * - FREQ
+       * - TIME
+       * - EMS
+       * - EXS
+       * - ANGLE
+       */
+      if (isDigit(c)) {
+        return this.numberToken(c, pos);
+      }
+
+      /*
+       * Potential tokens:
+       * - IDENT
+       * - CHAR
+       * - PLUS
+       */
+      return isIdentStart(c) ?
+        this.identOrFunctionToken(c, pos) :
+        this.charToken(c, pos);
+    }
+
+    /**
+     * Produces a token based on available data and the current
+     * reader position information. This method is called by other
+     * private methods to create tokens and is never called directly.
+     */
+    createToken(type, value, pos, opts) {
+      const token = {
+        value,
+        type,
+        startLine: pos.line,
+        startCol: pos.col,
+        offset: pos.offset,
+      };
+      if (opts && opts.endChar) token.endChar = opts.endChar;
+      return token;
+    }
+
+    /**
+     * Produces a token for any at-rule. If the at-rule is unknown, then
+     * the token is for a single "@" character.
+     * @param {String} first The first character for the token.
+     */
+    atRuleToken(first, pos) {
+      const reader = this._reader;
+      let rule = first;
+      let tt = Tokens.CHAR;
+
+      /*
+       * First, mark where we are. There are only four @ rules,
+       * so anything else is really just an invalid token.
+       * Basically, if this doesn't match one of the known @
+       * rules, just return '@' as an unknown token and allow
+       * parsing to continue after that point.
+       */
+      reader.mark();
+
+      // try to find the at-keyword
+      const ident = this.readName();
+      rule = first + ident;
+      tt = Tokens.type(lower(rule));
+
+      // if it's not valid, use the first character only and reset the reader
+      if (tt === Tokens.CHAR || tt === Tokens.UNKNOWN) {
+        if (rule.length > 1) {
+          tt = Tokens.UNKNOWN_SYM;
+        } else {
+          tt = Tokens.CHAR;
+          rule = first;
+          reader.reset();
+        }
+      }
+
+      return this.createToken(tt, rule, pos);
+    }
+
+    /**
+     * Produces a character token based on the given character
+     * and location in the stream. If there's a special (non-standard)
+     * token name, this is used; otherwise CHAR is used.
+     * @param {String} c The character for the token.
+     */
+    charToken(c, pos) {
+      let tt = Tokens.type(c);
+      const opts = {};
+
+      if (tt === -1) {
+        tt = Tokens.CHAR;
+      } else {
+        opts.endChar = Tokens[tt].endChar;
+      }
+
+      return this.createToken(tt, c, pos, opts);
+    }
+
+    /**
+     * Produces a character token based on the given character
+     * and location in the stream. If there's a special (non-standard)
+     * token name, this is used; otherwise CHAR is used.
+     * @param {String} first The first character for the token.
+     */
+    commentToken(first, pos) {
+      const comment = this.readComment(first);
+      const isUsoVar = comment.startsWith('/*[[') && comment.endsWith(']]*/');
+      return this.createToken(isUsoVar ? Tokens.USO_VAR : Tokens.COMMENT, comment, pos);
+    }
+
+    /**
+     * Produces a comparison token based on the given character
+     * and location in the stream. The next character must be
+     * read and is already known to be an equals sign.
+     * @param {String} c The character for the token.
+     */
+    comparisonToken(c, pos) {
+      const reader = this._reader;
+      const comparison = c + reader.read();
+      const tt = Tokens.type(comparison) || Tokens.CHAR;
+      return this.createToken(tt, comparison, pos);
+    }
+
+    /**
+     * Produces a hash token based on the specified information. The
+     * first character provided is the pound sign (#) and then this
+     * method reads a name afterward.
+     * @param {String} first The first character (#) in the hash name.
+     */
+    hashToken(first, pos) {
+      const name = this.readName(first);
+      return this.createToken(Tokens.HASH, name, pos);
+    }
+
+    /**
+     * Produces a CDO or CHAR token based on the specified information. The
+     * first character is provided and the rest is read by the function to determine
+     * the correct token to create.
+     * @param {String} first The first character in the token.
+     */
+    htmlCommentStartToken(first, pos) {
+      const reader = this._reader;
+      let text = first;
+
+      reader.mark();
+      text += reader.readCount(3);
+
+      if (text === '<!--') {
+        return this.createToken(Tokens.CDO, text, pos);
+      } else {
+        reader.reset();
+        return this.charToken(first, pos);
+      }
+    }
+
+    /**
+     * Produces a CDC or CHAR token based on the specified information. The
+     * first character is provided and the rest is read by the function to determine
+     * the correct token to create.
+     * @param {String} first The first character in the token.
+     */
+    htmlCommentEndToken(first, pos) {
+      const reader = this._reader;
+      let text = first;
+
+      reader.mark();
+      text += reader.readCount(2);
+
+      if (text === '-->') {
+        return this.createToken(Tokens.CDC, text, pos);
+      } else {
+        reader.reset();
+        return this.charToken(first, pos);
+      }
+    }
+
+    /**
+     * Produces an IDENT or FUNCTION token based on the specified information. The
+     * first character is provided and the rest is read by the function to determine
+     * the correct token to create.
+     * @param {String} first The first character in the identifier.
+     */
+    identOrFunctionToken(first, pos) {
+      const reader = this._reader;
+      const uriFns = ['url', 'url-prefix', 'domain'];
+
+      const name = this.readName(first);
+
+      switch (reader.peek()) {
+
+        // might be a URI or function
+        case '(':
+          reader.read();
+          if (uriFns.includes(lower(name))) {
+            reader.mark();
+            const uri = this.readURI(name + '(');
+            if (uri) {
+              const token = this.createToken(Tokens.URI, uri.text, pos);
+              token.name = name;
+              token.uri = uri.value;
+              return token;
+            }
+            reader.reset();
+          }
+          return this.createToken(Tokens.FUNCTION, name + '(', pos);
+
+        // might be an IE function
+        case ':':
+          // IE-specific functions always being with progid:
+          if (lower(name) === 'progid') {
+            return this.createToken(Tokens.IE_FUNCTION, name + reader.readTo('('), pos);
+          }
+      }
+
+      const type = name.startsWith('--') ? Tokens.CUSTOM_PROP : Tokens.IDENT;
+      return this.createToken(type, name, pos);
+    }
+
+    /**
+     * Produces an IMPORTANT_SYM or CHAR token based on the specified information. The
+     * first character is provided and the rest is read by the function to determine
+     * the correct token to create.
+     * @param {String} first The first character in the token.
+     */
+    importantToken(first, pos) {
+      const reader = this._reader;
+      let text = first;
+
+      reader.mark();
+
+      for (let pass = 1; pass++ <= 2;) {
+        const important = reader.readMatch(/\s*important\b/iy);
+        if (important) {
+          return this.createToken(Tokens.IMPORTANT_SYM, text + important, pos);
+        }
+        const comment = reader.readMatch('/*');
+        if (!comment) break;
+        text += comment + this.readComment(comment);
+      }
+
+      reader.reset();
+
+      return this.charToken(first, pos);
+    }
+
+    /**
+     * Produces a NOT or ANY or CHAR token based on the specified information. The
+     * first character is provided and the rest is read by the function to determine
+     * the correct token to create.
+     * @param {String} first The first character in the token.
+     */
+    notOrAnyToken(first, pos) {
+      const reader = this._reader;
+      const func = reader.readMatch(/not\(|(-(moz|webkit)-)?any\(/iy);
+      if (func) {
+        const type = /^n/i.test(func) ? Tokens.NOT : Tokens.ANY;
+        return this.createToken(type, first + func, pos);
+      }
+      return this.charToken(first, pos);
+    }
+
+    /**
+     * Produces a number token based on the given character
+     * and location in the stream. This may return a token of
+     * NUMBER, EMS, EXS, LENGTH, ANGLE, TIME, FREQ, DIMENSION,
+     * or PERCENTAGE.
+     * @param {String} first The first character for the token.
+     */
+    numberToken(first, pos) {
+      const reader = this._reader;
+      const value = this.readNumber(first);
+      let tt = Tokens.NUMBER;
+      let units, type;
+
+      const c = reader.peek();
+      if (isIdentStart(c)) {
+        units = this.readName(reader.read());
+        type = UNITS[lower(units)];
+        tt = type && Tokens[type.toUpperCase()] ||
+             type === 'frequency' && Tokens.FREQ ||
+             Tokens.DIMENSION;
+      } else if (c === '%') {
+        units = reader.read();
+        type = 'percentage';
+        tt = Tokens.PERCENTAGE;
+      } else {
+        type = 'number';
+      }
+
+      const token = this.createToken(tt, units ? value + units : value, pos);
+      token.number = parseFloat(value);
+      if (units) token.units = units;
+      if (type) token.unitsType = type;
+      return token;
+    }
+
+    /**
+     * Produces a string token based on the given character
+     * and location in the stream. Since strings may be indicated
+     * by single or double quotes, a failure to match starting
+     * and ending quotes results in an INVALID token being generated.
+     * The first character in the string is passed in and then
+     * the rest are read up to and including the final quotation mark.
+     * @param {String} first The first character in the string.
+     */
+    stringToken(first, pos) {
+      const delim = first;
+      let string = first;
+      const reader = this._reader;
+      let tt = Tokens.STRING;
+      let c = reader.read();
+      let i;
+
+      while (c) {
+        string += c;
+
+        if (c === '\\') {
+          c = reader.read();
+          if (c === null) {
+            break; // premature EOF after backslash
+          } else if (/[^\r\n\f0-9a-f]/i.test(c)) {
+            // single-character escape
+            string += c;
+          } else {
+            // read up to six hex digits
+            for (i = 0; isHexDigit(c) && i < 6; i++) {
+              string += c;
+              c = reader.read();
+            }
+            // swallow trailing newline or space
+            if (c === '\r' && reader.peek() === '\n') {
+              string += c;
+              c = reader.read();
+            }
+            if (isWhitespace(c)) {
+              string += c;
+            } else {
+              // This character is null or not part of the escape;
+              // jump back to the top to process it.
+              continue;
+            }
+          }
+        } else if (c === delim) {
+          break; // delimiter found.
+        } else if (isNewLine(reader.peek())) {
+          // newline without an escapement: it's an invalid string
+          tt = Tokens.INVALID;
+          break;
+        }
+        c = reader.read();
+      }
+
+      // if c is null, that means we're out of input and the string was never closed
+      if (c === null) {
+        tt = Tokens.INVALID;
+      }
+
+      return this.createToken(tt, string, pos);
+    }
+
+    unicodeRangeToken(first, pos) {
+      const reader = this._reader;
+
+      if (reader.peek() !== '+') {
+        return this.createToken(Tokens.CHAR, first, pos);
+      }
+
+      reader.mark();
+      reader.read();
+      let value = first + '+';
+
+      let chunk = this.readUnicodeRangePart(true);
+      if (!chunk) {
+        reader.reset();
+        return this.createToken(Tokens.CHAR, value, pos);
+      }
+
+      value += chunk;
+
+      // if there's a ? in the first part, there can't be a second part
+      if (!value.includes('?') && reader.peek() === '-') {
+        reader.mark();
+        reader.read();
+        chunk = this.readUnicodeRangePart(false);
+        if (!chunk) {
+          reader.reset();
+        } else {
+          value += '-' + chunk;
+        }
+      }
+
+      return this.createToken(Tokens.UNICODE_RANGE, value, pos);
+    }
+
+    /**
+     * Produces a S token based on the specified information. Since whitespace
+     * may have multiple characters, this consumes all whitespace characters
+     * into a single token.
+     * @param {String} first The first character in the token.
+     */
+    whitespaceToken(first, pos) {
+      const value = first + this.readWhitespace();
+      return this.createToken(Tokens.S, value, pos);
+    }
+
+    //-------------------------------------------------------------------------
+    // Methods to read values from the string stream
+    //-------------------------------------------------------------------------
+
+    readUnicodeRangePart(allowQuestionMark) {
+      const reader = this._reader;
+      let part = reader.readMatch(/[0-9a-f]{1,6}/iy);
+      if (allowQuestionMark &&
+          part.length < 6 &&
+          reader.peek() === '?') {
+        part += reader.readMatch(new RegExp(`\\?{1,${6 - part.length}}`, 'y'));
+      }
+      return part;
+    }
+
+    readWhitespace() {
+      return this._reader.readMatch(/\s+/y) || '';
+    }
+
+    readNumber(first) {
+      const tail = this._reader.readMatch(
+        first === '.' ?
+          /\d+(e[+-]?\d+)?/iy :
+        isDigit(first) ?
+          /\d*\.?\d*(e[+-]?\d+)?/iy :
+          /(\d*\.\d+|\d+\.?\d*)(e[+-]?\d+)?/iy);
+      return first + (tail || '');
+    }
+
+    // returns null w/o resetting reader if string is invalid.
+    readString() {
+      const token = this.stringToken(this._reader.read(), 0, 0);
+      return token.type !== Tokens.INVALID ? token.value : null;
+    }
+
+    // returns null w/o resetting reader if URI is invalid.
+    readURI(first) {
+      const reader = this._reader;
+
+      const uri = first;
+      let value = '';
+
+      this.readWhitespace();
+
+      if (/['"]/.test(reader.peek())) {
+        value = this.readString();
+        if (value === null) return null;
+        value = PropertyValuePart.parseString(value);
+      } else {
+        value = this.readUnquotedURL();
+      }
+
+      this.readWhitespace();
+      if (reader.peek() !== ')') return null;
+
+      // Ensure argument to URL is always double-quoted
+      // (This simplifies later processing in PropertyValuePart.)
+      return {value, text: uri + PropertyValuePart.serializeString(value) + reader.read()};
+    }
+
+    // This method never fails, although it may return an empty string.
+    readUnquotedURL(first) {
+      const reader = this._reader;
+      let url = first || '';
+      let c;
+
+      for (c = reader.peek(); c; c = reader.peek()) {
+        // Note that the grammar at
+        // https://www.w3.org/TR/CSS2/grammar.html#scanner
+        // incorrectly includes the backslash character in the
+        // `url` production, although it is correctly omitted in
+        // the `baduri1` production.
+        if (/^[\u00A0-\uFFFF]$/.test(c) || /^[-!#$%&*-[\]-~]$/.test(c)) {
+          url += c;
+          reader.read();
+        } else if (c === '\\') {
+          if (/^[^\r\n\f]$/.test(reader.peek(2))) {
+            url += this.readEscape(reader.read());
+          } else {
+            break; // bad escape sequence.
+          }
+        } else {
+          break; // bad character
+        }
+      }
+
+      return url;
+    }
+
+    readName(first) {
+      const reader = this._reader;
+      const ident = [first || ''];
+
+      do {
+        const chunk = reader.readMatch(/[-_\da-zA-Z\u00A0-\uFFFF]*/y);
+        ident.push(chunk);
+        reader.mark();
+        const c = reader.read();
+        if (c === '\\' && /^[^\r\n\f]$/.test(reader.peek())) {
+          ident.push(this.readEscape(c));
+        } else {
+          reader.reset();
+          break;
+        }
+      } while (true);
+
+      return ident.length > 2 ? ident.join('') : ident.length > 1 ? ident[0] + ident[1] : ident[0];
+    }
+
+    readEscape() {
+      const cp = this._reader.readMatch(/[0-9a-f]{1,6}\b\s*/iy);
+      return cp ? String.fromCodePoint(parseInt(cp, 16)) : this._reader.read();
+    }
+
+    readComment(first) {
+      return first +
+             this._reader.readCount(2 - first.length) +
+             this._reader.readMatch(/([^*]|\*(?!\/))*(\*\/|$)/y);
+    }
+  }
+
+  //-----------------------------------------------------------------------------
+  // Helper functions
+  //-----------------------------------------------------------------------------
+
+  function isHexDigit(c) {
+    return c !== null && (
+      c >= '0' && c <= '9' ||
+      c >= 'a' && c <= 'f' ||
+      c >= 'A' && c <= 'F');
+  }
+
+  function isDigit(c) {
+    return c !== null && c >= '0' && c <= '9';
+  }
+
+  function isWhitespace(c) {
+    return c !== null && (c === ' ' || c === '\t' || c === '\n' || c === '\f' || c === '\r');
+  }
+
+  function isNewLine(c) {
+    return c !== null && (c === '\n' || c === '\r\n' || c === '\r' || c === '\f');
+  }
+
+  function isNameStart(c) {
+    return c !== null && (
+      c >= 'a' && c <= 'z' ||
+      c >= 'A' && c <= 'Z' ||
+      c === '_' || c === '\\' ||
+      c >= '\u00A0' && c <= '\uFFFF');
+  }
+
+  function isNameChar(c) {
+    return c !== null && (c === '-' || c >= '0' && c <= '9' || isNameStart(c));
+  }
+
+  function isIdentStart(c) {
+    return c !== null && (c === '-' || isNameStart(c));
+  }
+
+  function isPseudoElement(pseudo) {
+    if (pseudo.startsWith('::')) return true;
+    switch (lower(pseudo)) {
+      case ':first-letter':
+      case ':first-line':
+      case ':before':
+      case ':after':
+        return true;
+    }
+  }
+
+  //endregion
+  //region ValidationTypes - methods
+
+  Object.assign(ValidationTypes, {
+
+    isLiteral(part, literals) {
+      const args = literals.includes(' | ') ? literals.split(' | ') : [literals];
+      const {text} = part;
+      let textLo;
+
+      for (const arg of args) {
+
+        if (arg[0] === '<') {
+          const simple = this.simple[arg];
+          if (simple && simple.call(this.simple, part)) {
+            return true;
+          }
+          continue;
+        }
+
+        if (arg.endsWith('()')) {
+          if (!part.name || part.name.length !== arg.length - 2) continue;
+          const name = arg.slice(0, -2);
+          if (part.name === name ||
+              lower(arg).startsWith((textLo = textLo || lower(text)).slice(0, name.length))) {
+            // empty function parameter means the initial value is used
+            if (!part.expr) return this.functionsMayBeEmpty.has(name);
+            const fn = this.functions[name];
+            if (!fn) return true;
+            const expression = new PropertyValueIterator(part.expr);
+            if (fn.match(expression) && !expression.hasNext()) {
+              return true;
+            }
+            const {text} = expression.value;
+            throw new ValidationError(`Expected '${this.explode(String(fn))}' but found '${text}'.`,
+              expression.value);
+          }
+          continue;
+        }
+
+        let argLo;
+        if (text === arg ||
+            (textLo = textLo || lower(text)) === (argLo = argLo || lower(arg)) ||
+            text[0] === '-' && (
+              textLo.startsWith('-webkit-') ||
+              textLo.startsWith('-moz-') ||
+              textLo.startsWith('-ms-') ||
+              textLo.startsWith('-o-')
+            ) && textLo.slice(textLo.indexOf('-', 1) + 1) === argLo) {
+          return true;
+        }
+
+      }
+      return false;
+    },
+
+    describe(type) {
+      const complex = this.complex[type];
+      const text = complex instanceof Matcher ? complex.toString(0) : type;
+      return this.explode(text);
+    },
+
+    explode(text) {
+      if (!text.includes('<')) return text;
+      return text
+        .replace(' | <var>', '')
+        .replace(/(<.*?>)([{#?]?)/g,
+          (_, rule, mod) => {
+            const ref = this.simple[rule] || this.complex[rule];
+            if (!ref || !ref.originalText) return rule + mod;
+            return ((mod ? '[' : '') + this.explode(ref.originalText) + (mod ? ']' : '')) + mod;
+          });
+    },
+
+    /**
+     * Determines if the next part(s) of the given expression
+     * are of a given type.
+     */
+    isType(expression, type) {
+      const part = expression.peek();
+      let result;
+
+      if (this.simple['<var>'](part)) {
+        result = true;
+
+      } else if (type.charAt(0) !== '<') {
+        result = this.isLiteral(part, type);
+
+      } else if (this.simple[type]) {
+        result = this.simple[type](part);
+
+      } else {
+        return this.complex[type] instanceof Matcher ?
+          this.complex[type].match(expression) :
+          this.complex[type](expression);
+      }
+
+      if (result) expression.next();
+      return result;
+    },
+  });
+
+  {
+    let action = rule => part => ValidationTypes.isLiteral(part, rule);
+    ['simple', 'complex', 'functions'].forEach(name => {
+      const set = ValidationTypes[name];
+      for (const id in set) {
+        const rule = set[id];
+        if (typeof rule === 'string') {
+          set[id] = Object.defineProperty(action(rule), 'originalText', {value: rule});
+        } else if (/^Matcher\s/.test(rule)) {
+          set[id] = rule(Matcher);
+        }
+      }
+      action = rule => Matcher.parse(rule);
+    });
+  }
+
+  //endregion
+  //region Validation
+
+  const validationCache = new Map();
+
+  function validateProperty(property, value) {
+    // All properties accept some CSS-wide values.
+    // https://drafts.csswg.org/css-values-3/#common-keywords
+    if (/^(inherit|initial|unset)$/i.test(value.parts[0])) {
+      if (value.parts.length > 1) {
+        throwEndExpected(value.parts[1], true);
+      }
+      return;
+    }
+
+    const prop = lower(property);
+    let known = validationCache.get(prop);
+    if (known && known.has(value.text)) return;
+
+    const spec = Properties[prop] || /^-(webkit|moz|ms|o)-(.+)/i.test(prop) && Properties[RegExp.$2];
+
+    if (typeof spec === 'number') return;
+    if (!spec && prop.startsWith('-')) return;
+    if (!spec) throw new ValidationError(`Unknown property '${property}'.`, property);
+
+    // Property-specific validation.
+    const expression = new PropertyValueIterator(value);
+    const result = Matcher.parse(spec).match(expression);
+
+    const hasNext = expression.hasNext();
+    if (result) {
+      if (hasNext) throwEndExpected(expression.next());
+
+    } else {
+      if (hasNext && expression._i) {
+        throwEndExpected(expression.peek());
+      } else {
+        const {text} = expression.value;
+        throw new ValidationError(`Expected '${ValidationTypes.describe(spec)}' but found '${text}'.`,
+          expression.value);
+      }
+    }
+
+    if (!known) validationCache.set(prop, (known = new Set()));
+    known.add(value.text);
+
+    function throwEndExpected(token, force) {
+      if (force || token.name !== 'var' || token.type !== 'function') {
+        throw new ValidationError(`Expected end of value but found '${token.text}'.`, token);
+      }
+    }
+  }
+
+  //endregion
+  //region Parser
+
+  class Parser extends EventTarget {
+    /**
+     * A CSS3 parser.
+     * @param {Object} options (Optional) Various options for the parser:
+     *      starHack (true|false) to allow IE6 star hack as valid,
+     *      underscoreHack (true|false) to interpret leading underscores
+     *      as IE6-7 targeting for known properties, ieFilters (true|false)
+     *      to indicate that IE < 8 filters should be accepted and not throw
+     *      syntax errors.
+     */
+    constructor(options) {
+      super();
+      this.options = options || {};
+      this._tokenStream = null;
+    }
+
+    fire(event, token = this._tokenStream._token) {
+      if (typeof event === 'string') {
+        event = {type: event};
+      } else if (event.message && event.message.includes('/*[[')) {
+        return;
+      }
+      if (event.offset === undefined && token) {
+        event.offset = token.offset;
+        if (event.line === undefined) event.line = token.startLine || token.line;
+        if (event.col === undefined) event.col = token.startCol || token.col;
+      }
+      if (token !== false) parserCache.addEvent(event);
+      return super.fire(event);
+    }
+    /*
+     * stylesheet
+     *  : [ CHARSET_SYM S* STRING S* ';' ]?
+     *    [S|CDO|CDC]* [ import [S|CDO|CDC]* ]*
+     *    [ namespace [S|CDO|CDC]* ]*
+     *    [ [ ruleset | media | page | font_face | keyframes_rule | supports_rule ] [S|CDO|CDC]* ]*
+     *  ;
+     */
+    _stylesheet() {
+      const stream = this._tokenStream;
+      let tt;
+
+      this.fire('startstylesheet');
+
+      this._charset();
+
+      this._skipCruft();
+
+      while (stream.peek() === Tokens.IMPORT_SYM) {
+        this._import();
+        this._skipCruft();
+      }
+
+      while (stream.peek() === Tokens.NAMESPACE_SYM) {
+        this._namespace();
+        this._skipCruft();
+      }
+
+      while ((tt = stream.peek()) > Tokens.EOF) {
+        try {
+          switch (tt) {
+
+            case Tokens.MEDIA_SYM:
+              this._media();
+              this._skipCruft();
+              continue;
+
+            case Tokens.PAGE_SYM:
+              this._page();
+              this._skipCruft();
+              continue;
+
+            case Tokens.FONT_FACE_SYM:
+              this._fontFace();
+              this._skipCruft();
+              continue;
+
+            case Tokens.KEYFRAMES_SYM:
+              this._keyframes();
+              this._skipCruft();
+              continue;
+
+            case Tokens.VIEWPORT_SYM:
+              this._viewport();
+              this._skipCruft();
+              continue;
+
+            case Tokens.DOCUMENT_SYM:
+              this._document();
+              this._skipCruft();
+              continue;
+
+            case Tokens.SUPPORTS_SYM:
+              this._supports();
+              this._skipCruft();
+              continue;
+
+            case Tokens.UNKNOWN_SYM: {
+              stream.get();
+              const lt0 = stream.LT(0);
+              if (this.options.strict) {
+                throw new SyntaxError('Unknown @ rule.', lt0);
+              }
+
+              this.fire({
+                type:    'error',
+                error:   null,
+                message: 'Unknown @ rule: ' + lt0.value + '.',
+              }, lt0);
+
+              // skip {} block
+              let count = 0;
+              do {
+                const brace = stream.advance([Tokens.LBRACE, Tokens.RBRACE]);
+                count += brace === Tokens.LBRACE ? 1 : -1;
+              } while (count > 0 && !stream._reader.eof());
+              if (count < 0) stream.unget();
+              continue;
+            }
+            case Tokens.S:
+              this._ws();
+              continue;
+
+            default: {
+              if (this._ruleset()) continue;
+
+              let token;
+              // error handling for known issues
+              switch (tt) {
+                case Tokens.CHARSET_SYM:
+                  token = stream.LT(1);
+                  this._charset(false);
+                  throw new SyntaxError('@charset not allowed here.', token);
+
+                case Tokens.IMPORT_SYM:
+                  token = stream.LT(1);
+                  this._import(false);
+                  throw new SyntaxError('@import not allowed here.', token);
+
+                case Tokens.NAMESPACE_SYM:
+                  token = stream.LT(1);
+                  this._namespace(false);
+                  throw new SyntaxError('@namespace not allowed here.', token);
+
+                default:
+                  stream.get();
+                  this._unexpectedToken(stream._token);
+              }
+            }
+          }
+        } catch (ex) {
+          if (ex instanceof SyntaxError && !this.options.strict) {
+            this.fire(Object.assign({}, ex, {type: 'error', error: ex}));
+          } else {
+            throw ex;
+          }
+        }
+      }
+
+      if (stream.peek() !== Tokens.EOF) {
+        this._unexpectedToken(stream._token);
+      }
+
+      this.fire('endstylesheet');
+    }
+
+    _charset(emit) {
+      const stream = this._tokenStream;
+      if (!stream.match(Tokens.CHARSET_SYM)) return;
+
+      const start = stream._token;
+      this._ws();
+
+      stream.mustMatch(Tokens.STRING);
+      const charset = stream._token.value;
+      this._ws();
+
+      stream.mustMatch(Tokens.SEMICOLON);
+
+      if (emit !== false) {
+        this.fire({
+          type: 'charset',
+          charset,
+        }, start);
+      }
+    }
+
+    _import(emit) {
+      /*
+       * import
+       *   : IMPORT_SYM S*
+       *    [STRING|URI] S* media_query_list? ';' S*
+       */
+      const stream = this._tokenStream;
+
+      stream.mustMatch(Tokens.IMPORT_SYM);
+      const start = stream._token;
+
+      this._ws();
+      stream.mustMatch([Tokens.STRING, Tokens.URI]);
+      const uri = stream._token.value.replace(/^(?:url\()?["']?([^"']+?)["']?\)?$/, '$1');
+
+      this._ws();
+      const mediaList = this._mediaQueryList();
+
+      // must end with a semicolon
+      stream.mustMatch(Tokens.SEMICOLON);
+      this._ws();
+
+      if (emit !== false) {
+        this.fire({
+          type: 'import',
+          media: mediaList,
+          uri,
+        }, start);
+      }
+
+    }
+
+    /*
+     * namespace
+     *   : NAMESPACE_SYM S* [namespace_prefix S*]? [STRING|URI] S* ';' S*
+     */
+    _namespace(emit) {
+      const stream = this._tokenStream;
+      let prefix;
+
+      // read import symbol
+      stream.mustMatch(Tokens.NAMESPACE_SYM);
+      const start = stream._token;
+      this._ws();
+
+      // it's a namespace prefix - no _namespace_prefix() method because it's just an IDENT
+      if (stream.match(Tokens.IDENT)) {
+        prefix = stream._token.value;
+        this._ws();
+      }
+
+      stream.mustMatch([Tokens.STRING, Tokens.URI]);
+      const uri = stream._token.value.replace(/(?:url\()?["']([^"']+)["']\)?/, '$1');
+
+      this._ws();
+
+      stream.mustMatch(Tokens.SEMICOLON);
+      this._ws();
+
+      if (emit !== false) {
+        this.fire({
+          type: 'namespace',
+          prefix,
+          uri,
+        }, start);
+      }
+    }
+
+    /*
+     * supports_rule
+     *  : SUPPORTS_SYM S* supports_condition S* group_rule_body
+     *  ;
+     */
+    _supports(emit) {
+      const stream = this._tokenStream;
+      if (!stream.match(Tokens.SUPPORTS_SYM)) return;
+
+      const start = stream._token;
+      this._ws();
+
+      this._supportsCondition();
+      this._ws();
+
+      stream.mustMatch(Tokens.LBRACE);
+      this._ws();
+
+      if (emit !== false) {
+        this.fire('startsupports', start);
+      }
+
+      while (this._ruleset()) { /*NOP*/ }
+
+      let error;
+      const token = stream.LT(1);
+      if (token.type === Tokens.MEDIA_SYM) {
+        this._media();
+        error = new SyntaxError('@media not allowed here.', token);
+      }
+
+      stream.mustMatch(Tokens.RBRACE);
+
+      if (emit !== false) {
+        this.fire('endsupports');
+      }
+
+      this._ws();
+
+      if (error) throw error;
+    }
+
+    /*
+     * supports_condition
+     *  : supports_negation | supports_conjunction | supports_disjunction |
+     *    supports_condition_in_parens
+     *  ;
+     */
+    _supportsCondition() {
+      const stream = this._tokenStream;
+      if (stream.match(Tokens.IDENT)) {
+        const ident = lower(stream._token.value);
+        if (ident === 'not') {
+          stream.mustMatch(Tokens.S);
+          this._supportsConditionInParens();
+        } else {
+          stream.unget();
+        }
+      } else {
+        this._supportsConditionInParens();
+        this._ws();
+        while (stream.peek() === Tokens.IDENT) {
+          const ident = lower(stream.LT(1).value);
+          if (ident === 'and' || ident === 'or') {
+            stream.mustMatch(Tokens.IDENT);
+            this._ws();
+            this._supportsConditionInParens();
+            this._ws();
+          }
+        }
+      }
+    }
+
+    /*
+     * supports_condition_in_parens
+     *  : ( '(' S* supports_condition S* ')' ) | supports_declaration_condition |
+     *    general_enclosed
+     *  ;
+     */
+    _supportsConditionInParens() {
+      const stream = this._tokenStream;
+      if (stream.match(Tokens.LPAREN)) {
+        this._ws();
+        if (stream.match(Tokens.IDENT)) {
+          // look ahead for not keyword,
+          // if not given, continue with declaration condition.
+          const ident = lower(stream._token.value);
+          if (ident === 'not') {
+            this._ws();
+            this._supportsCondition();
+            this._ws();
+            stream.mustMatch(Tokens.RPAREN);
+          } else {
+            stream.unget();
+            this._supportsDeclarationCondition(false);
+          }
+        } else {
+          this._supportsCondition();
+          this._ws();
+          stream.mustMatch(Tokens.RPAREN);
+        }
+      } else {
+        this._supportsDeclarationCondition();
+      }
+    }
+
+    /*
+     * supports_declaration_condition
+     *  : '(' S* declaration ')'
+     *  ;
+     */
+    _supportsDeclarationCondition(requireStartParen) {
+      if (requireStartParen !== false) {
+        this._tokenStream.mustMatch(Tokens.LPAREN);
+      }
+      this._ws();
+      this._declaration();
+      this._tokenStream.mustMatch(Tokens.RPAREN);
+    }
+
+    /*
+     * media
+     *   : MEDIA_SYM S* media_query_list S* '{' S* ruleset* '}' S*
+     *   ;
+     */
+    _media() {
+      const stream = this._tokenStream;
+
+      stream.mustMatch(Tokens.MEDIA_SYM);
+      const start = stream._token;
+
+      this._ws();
+      const mediaList = this._mediaQueryList();
+
+      stream.mustMatch(Tokens.LBRACE);
+      this._ws();
+
+      this.fire({
+        type: 'startmedia',
+        media: mediaList,
+      }, start);
+
+      const actions = new Map([
+        [Tokens.PAGE_SYM, this._page],
+        [Tokens.FONT_FACE_SYM, this._fontFace],
+        [Tokens.VIEWPORT_SYM, this._viewport],
+        [Tokens.DOCUMENT_SYM, this._document],
+        [Tokens.SUPPORTS_SYM, this._supports],
+        [Tokens.MEDIA_SYM, this._media],
+      ]);
+      let action;
+      do action = actions.get(stream.peek());
+      while (action ? action.call(this) || true : this._ruleset());
+
+      stream.mustMatch(Tokens.RBRACE);
+
+      this.fire({
+        type: 'endmedia',
+        media: mediaList,
+      });
+
+      this._ws();
+    }
+
+    /*
+     * media_query_list
+     *   : S* [media_query [ ',' S* media_query ]* ]?
+     *   ;
+     */
+    _mediaQueryList() {
+      const stream = this._tokenStream;
+      const mediaList = [];
+
+      this._ws();
+      if ([Tokens.IDENT, Tokens.LPAREN].includes(stream.peek())) {
+        mediaList.push(this._mediaQuery());
+      }
+
+      while (stream.match(Tokens.COMMA)) {
+        this._ws();
+        mediaList.push(this._mediaQuery());
+      }
+
+      return mediaList;
+    }
+
+    /*
+     * Note: "expression" in the grammar maps to the _media_expression method.
+     *
+     * media_query
+     *   : [ONLY | NOT]? S* media_type S* [ AND S* expression ]*
+     *   | expression [ AND S* expression ]*
+     *   ;
+     */
+    _mediaQuery() {
+      const stream = this._tokenStream;
+      let type = null;
+      let ident = null;
+      let token = null;
+      const expressions = [];
+
+      if (stream.match(Tokens.IDENT)) {
+        ident = lower(stream._token.value);
+
+        // since there's no custom tokens for these, need to manually check
+        if (ident !== 'only' && ident !== 'not') {
+          stream.unget();
+          ident = null;
+        } else {
+          token = stream._token;
+        }
+      }
+
+      this._ws();
+
+      if (stream.peek() === Tokens.IDENT) {
+        type = this._mediaType();
+        if (token === null) {
+          token = stream._token;
+        }
+      } else if (stream.peek() === Tokens.LPAREN) {
+        if (token === null) {
+          token = stream.LT(1);
+        }
+        expressions.push(this._mediaExpression());
+      }
+
+      if (type === null && expressions.length === 0) return null;
+
+      this._ws();
+      while (stream.match(Tokens.IDENT)) {
+        if (lower(stream._token.value) !== 'and') {
+          this._unexpectedToken(stream._token);
+        }
+        this._ws();
+        expressions.push(this._mediaExpression());
+      }
+
+      return new MediaQuery(ident, type, expressions, token);
+    }
+
+    /*
+     * media_type
+     *   : IDENT
+     *   ;
+     */
+    _mediaType() {
+      return this._mediaFeature();
+    }
+
+    /**
+     * Note: in CSS3 Media Queries, this is called "expression".
+     * Renamed here to avoid conflict with CSS3 Selectors
+     * definition of "expression". Also note that "expr" in the
+     * grammar now maps to "expression" from CSS3 selectors.
+     * @method _media_expression
+     * @private
+     *
+     * expression
+     *  : '(' S* media_feature S* [ ':' S* expr ]? ')' S*
+     *  ;
+     */
+    _mediaExpression() {
+      const stream = this._tokenStream;
+      let feature = null;
+      let token;
+      let expression = null;
+
+      stream.mustMatch(Tokens.LPAREN);
+
+      feature = this._mediaFeature();
+      this._ws();
+
+      if (stream.match(Tokens.COLON)) {
+        this._ws();
+        token = stream.LT(1);
+        expression = this._expression();
+      }
+
+      stream.mustMatch(Tokens.RPAREN);
+      this._ws();
+
+      return new MediaFeature(feature, expression ? new SyntaxUnit(expression, token) : null);
+    }
+
+    /*
+     * media_feature
+     *   : IDENT
+     *   ;
+     */
+    _mediaFeature() {
+      this._ws();
+      this._tokenStream.mustMatch(Tokens.IDENT);
+      return SyntaxUnit.fromToken(this._tokenStream._token);
+    }
+
+    /*
+     * page:
+     *    PAGE_SYM S* IDENT? pseudo_page? S*
+     *    '{' S* [ declaration | margin ]? [ ';' S* [ declaration | margin ]? ]* '}' S*
+     *    ;
+     */
+    _page() {
+      const stream = this._tokenStream;
+      let identifier = null;
+      let pseudoPage = null;
+
+      // look for @page
+      stream.mustMatch(Tokens.PAGE_SYM);
+      const start = stream._token;
+
+      this._ws();
+
+      if (stream.match(Tokens.IDENT)) {
+        identifier = stream._token.value;
+
+        // The value 'auto' may not be used as a page name and MUST be treated as a syntax error.
+        if (lower(identifier) === 'auto') {
+          this._unexpectedToken(stream._token);
+        }
+      }
+
+      // see if there's a colon upcoming
+      if (stream.peek() === Tokens.COLON) {
+        pseudoPage = this._pseudoPage();
+      }
+
+      this._ws();
+
+      this.fire({
+        type:   'startpage',
+        id:     identifier,
+        pseudo: pseudoPage,
+      }, start);
+
+      this._readDeclarations({readMargins: true});
+
+      this.fire({
+        type:   'endpage',
+        id:     identifier,
+        pseudo: pseudoPage,
+      });
+    }
+
+    /*
+     * margin :
+     *    margin_sym S* '{' declaration [ ';' S* declaration? ]* '}' S*
+     *    ;
+     */
+    _margin() {
+      const margin = this._marginSym();
+      if (!margin) return false;
+
+      this.fire({
+        type: 'startpagemargin',
+        margin,
+      });
+
+      this._readDeclarations();
+
+      this.fire({
+        type: 'endpagemargin',
+        margin,
+      });
+
+      return true;
+    }
+
+    /*
+     * margin_sym :
+     *    TOPLEFTCORNER_SYM |
+     *    TOPLEFT_SYM |
+     *    TOPCENTER_SYM |
+     *    TOPRIGHT_SYM |
+     *    TOPRIGHTCORNER_SYM |
+     *    BOTTOMLEFTCORNER_SYM |
+     *    BOTTOMLEFT_SYM |
+     *    BOTTOMCENTER_SYM |
+     *    BOTTOMRIGHT_SYM |
+     *    BOTTOMRIGHTCORNER_SYM |
+     *    LEFTTOP_SYM |
+     *    LEFTMIDDLE_SYM |
+     *    LEFTBOTTOM_SYM |
+     *    RIGHTTOP_SYM |
+     *    RIGHTMIDDLE_SYM |
+     *    RIGHTBOTTOM_SYM
+     *    ;
+     */
+    _marginSym() {
+      if (this._tokenStream.match([
+        Tokens.TOPLEFTCORNER_SYM,
+        Tokens.TOPLEFT_SYM,
+        Tokens.TOPCENTER_SYM,
+        Tokens.TOPRIGHT_SYM,
+        Tokens.TOPRIGHTCORNER_SYM,
+        Tokens.BOTTOMLEFTCORNER_SYM,
+        Tokens.BOTTOMLEFT_SYM,
+        Tokens.BOTTOMCENTER_SYM,
+        Tokens.BOTTOMRIGHT_SYM,
+        Tokens.BOTTOMRIGHTCORNER_SYM,
+        Tokens.LEFTTOP_SYM,
+        Tokens.LEFTMIDDLE_SYM,
+        Tokens.LEFTBOTTOM_SYM,
+        Tokens.RIGHTTOP_SYM,
+        Tokens.RIGHTMIDDLE_SYM,
+        Tokens.RIGHTBOTTOM_SYM,
+      ])) {
+        return SyntaxUnit.fromToken(this._tokenStream._token);
+      } else {
+        return null;
+      }
+    }
+
+    /*
+     * pseudo_page
+     *   : ':' IDENT
+     *   ;
+     */
+    _pseudoPage() {
+      const stream = this._tokenStream;
+      stream.mustMatch(Tokens.COLON);
+      stream.mustMatch(Tokens.IDENT);
+      // TODO: CSS3 Paged Media says only "left", "center", and "right" are allowed
+      return stream._token.value;
+    }
+
+    /*
+     * font_face
+     *   : FONT_FACE_SYM S*
+     *     '{' S* declaration [ ';' S* declaration ]* '}' S*
+     *   ;
+     */
+    _fontFace() {
+      const stream = this._tokenStream;
+      stream.mustMatch(Tokens.FONT_FACE_SYM);
+
+      this.fire('startfontface');
+
+      this._ws();
+      this._readDeclarations();
+
+      this.fire('endfontface');
+    }
+
+    /*
+     * viewport
+     *   : VIEWPORT_SYM S*
+     *     '{' S* declaration? [ ';' S* declaration? ]* '}' S*
+     *   ;
+     */
+    _viewport() {
+      const stream = this._tokenStream;
+      stream.mustMatch(Tokens.VIEWPORT_SYM);
+
+      this.fire('startviewport');
+
+      this._ws();
+      this._readDeclarations();
+
+      this.fire('endviewport');
+    }
+
+    /*
+     * document
+     *   : DOCUMENT_SYM S*
+     *     _document_function [ ',' S* _document_function ]* S*
+     *     '{' S* ruleset* '}'
+     *   ;
+     */
+    _document() {
+      const stream = this._tokenStream;
+      const functions = [];
+      let prefix = '';
+
+      stream.mustMatch(Tokens.DOCUMENT_SYM);
+      const start = stream._token;
+      if (/^@-([^-]+)-/.test(start.value)) {
+        prefix = RegExp.$1;
+      }
+
+      do {
+        this._ws();
+        functions.push(this._documentFunction());
+      } while (stream.match(Tokens.COMMA));
+
+      this._ws();
+      stream.mustMatch(Tokens.LBRACE);
+
+      this.fire({
+        type: 'startdocument',
+        functions,
+        prefix,
+      }, start);
+
+      this._ws();
+
+      const actions = new Map([
+        [Tokens.PAGE_SYM, this._page],
+        [Tokens.FONT_FACE_SYM, this._fontFace],
+        [Tokens.VIEWPORT_SYM, this._viewport],
+        [Tokens.DOCUMENT_SYM, this._document],
+        [Tokens.SUPPORTS_SYM, this._supports],
+        [Tokens.MEDIA_SYM, this._media],
+        [Tokens.KEYFRAMES_SYM, this._keyframes],
+      ]);
+      let action;
+      do action = actions.get(stream.peek());
+      while (action ? action.call(this) || true : this._ruleset());
+
+      stream.mustMatch(Tokens.RBRACE);
+
+      this.fire({
+        type: 'enddocument',
+        functions,
+        prefix,
+      });
+
+      this._ws();
+    }
+
+    /*
+     * document_function
+     *   : function | URI S*
+     *   ;
+     */
+    _documentFunction() {
+      const stream = this._tokenStream;
+      return stream.match(Tokens.URI) ?
+        new PropertyValuePart(stream._token) :
+        this._function();
+    }
+
+    /*
+     * operator (outside function)
+     *  : '/' S* | ',' S* | /( empty )/
+     * operator (inside function)
+     *  : '/' S* | '+' S* | '*' S* | '-' S* /( empty )/
+     *  ;
+     */
+    _operator(inFunction) {
+      if (this._tokenStream.match([
+        Tokens.SLASH,
+        Tokens.COMMA,
+        ...(!inFunction ? [] : [
+          Tokens.PLUS,
+          Tokens.STAR,
+          Tokens.MINUS,
+        ])
+      ])) {
+        const value = new PropertyValuePart(this._tokenStream._token);
+        this._ws();
+        return value;
+      }
+      return null;
+    }
+
+    /*
+     * combinator
+     *  : PLUS S* | GREATER S* | TILDE S* | S+
+     *  ;
+     */
+    _combinator() {
+      if (this._tokenStream.match([Tokens.PLUS, Tokens.GREATER, Tokens.TILDE])) {
+        const value = new Combinator(this._tokenStream._token);
+        this._ws();
+        return value;
+      }
+      return null;
+    }
+
+    /*
+     * unary_operator
+     *  : '-' | '+'
+     *  ;
+     */
+    _unaryOperator() {
+      return this._tokenStream.match([Tokens.MINUS, Tokens.PLUS]) ?
+        this._tokenStream._token.value :
+        null;
+    }
+
+    /*
+     * property
+     *   : IDENT S*
+     *   ;
+     */
+    _property() {
+      const stream = this._tokenStream;
+      let value = null;
+      let hack = null;
+      let tokenValue, token, start;
+
+      // check for star hack - throws error if not allowed
+      if (stream.peek() === Tokens.STAR && this.options.starHack) {
+        stream.get();
+        token = stream._token;
+        start = token;
+        hack = token.value;
+      }
+
+      if (stream.match([Tokens.IDENT, Tokens.CUSTOM_PROP])) {
+        token = stream._token;
+        tokenValue = token.value;
+
+        // check for underscore hack - no error if not allowed because it's valid CSS syntax
+        if (tokenValue.charAt(0) === '_' && this.options.underscoreHack) {
+          hack = '_';
+          tokenValue = tokenValue.substring(1);
+        }
+
+        value = new PropertyName(tokenValue, hack, start || token);
+        this._ws();
+      }
+
+      return value;
+    }
+
+    /*
+     * ruleset
+     *   : selectors_group
+     *     '{' S* declaration? [ ';' S* declaration? ]* '}' S*
+     *   ;
+     */
+    _ruleset() {
+      try {
+        this._tokenStream._skipUsoVar();
+
+        if (parserCache.findBlock()) return true;
+        parserCache.startBlock();
+
+        const selectors = this._selectorsGroup();
+        if (!selectors) {
+          parserCache.cancelBlock();
+          return false;
+        }
+
+        parserCache.adjustBlockStart(selectors[0]);
+
+        this.fire({
+          type: 'startrule',
+          selectors,
+        }, selectors[0]);
+
+        this._readDeclarations({stopAfterBrace: true});
+
+        this.fire({
+          type: 'endrule',
+          selectors,
+        });
+
+        parserCache.endBlock();
+
+        this._ws();
+        return true;
+
+      } catch (ex) {
+        parserCache.cancelBlock();
+        if (!(ex instanceof SyntaxError) || this.options.strict) throw ex;
+        this.fire(Object.assign({}, ex, {type: 'error', error: ex}));
+        // if there's a right brace, the rule is finished so don't do anything
+        // otherwise, rethrow the error because it wasn't handled properly
+        if (this._tokenStream.advance([Tokens.RBRACE]) !== Tokens.RBRACE) throw ex;
+        // If even a single selector fails to parse, the entire ruleset should be thrown away,
+        // so we let the parser continue with the next one
+        return true;
+      }
+    }
+
+    /*
+     * selectors_group
+     *   : selector [ COMMA S* selector ]*
+     *   ;
+     */
+    _selectorsGroup() {
+      const selectors = [];
+      let selector, comma;
+
+      while ((selector = this._selector())) {
+        selectors.push(selector);
+        this._ws();
+        comma = this._tokenStream.match(Tokens.COMMA);
+        if (!comma) break;
+        this._ws();
+      }
+
+      if (comma) this._unexpectedToken(this._tokenStream.LT(1));
+
+      return selectors.length ? selectors : null;
+    }
+
+    /*
+     * selector
+     *   : simple_selector_sequence [ combinator simple_selector_sequence ]*
+     *   ;
+     */
+    _selector() {
+      const stream = this._tokenStream;
+      const selector = [];
+      let nextSelector = null;
+      let combinator = null;
+
+      nextSelector = this._simpleSelectorSequence();
+      if (!nextSelector) return null;
+
+      selector.push(nextSelector);
+
+      while (true) {
+        combinator = this._combinator();
+
+        if (combinator) {
+          selector.push(combinator);
+          nextSelector = this._simpleSelectorSequence();
+          if (nextSelector) {
+            selector.push(nextSelector);
+            continue;
+          }
+          this._unexpectedToken(stream.LT(1));
+          break;
+        }
+
+        if (!this._ws()) break;
+
+        // make a fallback whitespace combinator
+        const ws = new Combinator(stream._token);
+        // look for an explicit combinator
+        combinator = this._combinator();
+
+        // selector is required if there's a combinator
+        nextSelector = this._simpleSelectorSequence();
+        if (nextSelector) {
+          selector.push(combinator || ws);
+          selector.push(nextSelector);
+        } else if (combinator) {
+          this._unexpectedToken(stream.LT(1));
+        }
+      }
+
+      return new Selector(selector, selector[0]);
+    }
+
+    /*
+     * simple_selector_sequence
+     *   : [ type_selector | universal ]
+     *     [ HASH | class | attrib | pseudo | any | negation ]*
+     *   | [ HASH | class | attrib | pseudo | any | negation ]+
+     *   ;
+     */
+    _simpleSelectorSequence() {
+      const stream = this._tokenStream;
+      const start = stream._lt[stream._ltIndex] || stream.LT(1);
+      const modifiers = [];
+      let text = '';
+
+      const ns = this._namespacePrefix();
+      const elementName = this._typeSelector(ns) || this._universal(ns);
+      if (elementName) {
+        text += elementName;
+      } else if (ns) {
+        stream.unget();
+      }
+
+      while (true) {
+        const next = stream.peek();
+        const component =
+          next === Tokens.HASH && this._hash() ||
+          next === Tokens.DOT && this._class() ||
+          next === Tokens.LBRACKET && this._attrib() ||
+          next === Tokens.COLON && this._pseudo() ||
+          next === Tokens.ANY && this._any() ||
+          next === Tokens.NOT && this._negation();
+        if (!component) break;
+        modifiers.push(component);
+        text += component.toString();
+      }
+
+      return text && new SelectorPart(elementName, modifiers, text, start);
+    }
+
+    /*
+     * type_selector
+     *   : [ namespace_prefix ]? element_name
+     *   ;
+     */
+    _typeSelector(ns) {
+      const stream = this._tokenStream;
+      const nsSupplied = ns !== undefined;
+      ns = nsSupplied ? ns : this._namespacePrefix();
+      const elementName = this._elementName();
+
+      if (!elementName) {
+        if (!nsSupplied && ns && ns.length > 0) stream.unget();
+        if (!nsSupplied && ns && ns.length > 1) stream.unget();
+        return null;
+      }
+
+      if (ns) {
+        elementName.text = ns + elementName.text;
+        elementName.col -= ns.length;
+      }
+      return elementName;
+    }
+
+    _hash() {
+      const stream = this._tokenStream;
+      if (!stream.match(Tokens.HASH)) return null;
+      return new SelectorSubPart(stream._token.value, 'id', stream._token);
+    }
+
+    /*
+     * class
+     *   : '.' IDENT
+     *   ;
+     */
+    _class() {
+      if (!this._tokenStream.match(Tokens.DOT)) return null;
+      this._tokenStream.mustMatch(Tokens.IDENT);
+      const {value, startLine: line, startCol: col, offset} = this._tokenStream._token;
+      return new SelectorSubPart('.' + value, 'class', {line, col: col - 1, offset});
+    }
+
+    /*
+     * element_name
+     *   : IDENT
+     *   ;
+     */
+    _elementName() {
+      const stream = this._tokenStream;
+      if (!stream.match(Tokens.IDENT)) return null;
+      return new SelectorSubPart(stream._token.value, 'elementName', stream._token);
+    }
+
+    /*
+     * namespace_prefix
+     *   : [ IDENT | '*' ]? '|'
+     *   ;
+     */
+    _namespacePrefix() {
+      const stream = this._tokenStream;
+      const lt = stream._lt;
+      const i = stream._ltIndex;
+      if ((i < lt.length && lt[i].type || stream.LA(1)) !== Tokens.PIPE &&
+          (i + 1 < lt.length && lt[i + 1].type || stream.LA(2)) !== Tokens.PIPE) {
+        return null;
+      }
+      let value = '';
+      if (stream.match([Tokens.IDENT, Tokens.STAR])) {
+        value += stream._token.value;
+      }
+      stream.mustMatch(Tokens.PIPE);
+      return value + '|';
+    }
+
+    /*
+     * universal
+     *   : [ namespace_prefix ]? '*'
+     *   ;
+     */
+    _universal(ns = this._namespacePrefix()) {
+      return ((ns || '') + (this._tokenStream.match(Tokens.STAR) ? '*' : '')) || null;
+    }
+
+    /*
+     * attrib
+     *   : '[' S* [ namespace_prefix ]? IDENT S*
+     *         [ [ PREFIXMATCH |
+     *             SUFFIXMATCH |
+     *             SUBSTRINGMATCH |
+     *             '=' |
+     *             INCLUDES |
+     *             DASHMATCH ] S* [ IDENT | STRING ] S*
+     *         ]? ']'
+     *   ;
+     */
+    _attrib() {
+      const stream = this._tokenStream;
+
+      if (!stream.match(Tokens.LBRACKET)) return null;
+
+      const token = stream._token;
+      let value =
+        token.value +
+        this._ws() +
+        (this._namespacePrefix() || '');
+
+      stream.mustMatch(Tokens.IDENT);
+      value +=
+        stream._token.value +
+        this._ws();
+
+      if (stream.match([
+        Tokens.PREFIXMATCH,
+        Tokens.SUFFIXMATCH,
+        Tokens.SUBSTRINGMATCH,
+        Tokens.EQUALS,
+        Tokens.INCLUDES,
+        Tokens.DASHMATCH
+      ])) {
+        value += stream._token.value +
+                 this._ws();
+
+        stream.mustMatch([Tokens.IDENT, Tokens.STRING]);
+        value += stream._token.value +
+                 this._ws();
+
+        if (stream.match([Tokens.IDENT])) {
+          if (lower(stream._token.value) === 'i') {
+            value += stream._token.value +
+                     this._ws();
+          } else {
+            stream.unget();
+          }
+        }
+      }
+
+      stream.mustMatch(Tokens.RBRACKET);
+
+      return new SelectorSubPart(value + ']', 'attribute', token);
+    }
+
+    /*
+     * pseudo
+     *   : ':' ':'? [ IDENT | functional_pseudo ]
+     *   ;
+     */
+    _pseudo() {
+      const stream = this._tokenStream;
+      let pseudo = null;
+      let colons = ':';
+      let line, col, offset;
+
+      // read 1 or 2 colons
+      if (!stream.match(Tokens.COLON)) return null;
+      if (stream.match(Tokens.COLON)) colons += ':';
+
+      if (stream.match(Tokens.IDENT)) {
+        pseudo = stream._token.value;
+        line = stream._token.startLine;
+        col = stream._token.startCol - colons.length;
+        offset = stream._token.offset - colons.length;
+      } else if (stream.peek() === Tokens.FUNCTION) {
+        line = stream.LT(1).startLine;
+        col = stream.LT(1).startCol - colons.length;
+        offset = stream.LT(1).offset - colons.length;
+        if (stream.match(Tokens.FUNCTION)) {
+          pseudo =
+            stream._token.value +
+            this._ws() +
+            (this._expression({list: true}) || '') +
+            ')';
+          stream.mustMatch(Tokens.RPAREN);
+        }
+      }
+
+      if (pseudo) return new SelectorSubPart(colons + pseudo, 'pseudo', {line, col, offset});
+
+      const startLine = stream.LT(1).startLine;
+      const startCol = stream.LT(0).startCol;
+      throw new SyntaxError(
+        `Expected a 'FUNCTION' or 'IDENT' after colon at line ${startLine}, col ${startCol}.`,
+        {startLine, startCol});
+    }
+
+    /*
+     * expression
+     *   : [ [ PLUS | '-' | DIMENSION | NUMBER | STRING | IDENT ] S* ]+
+     *   ;
+     */
+    _expression({list = false} = {}) {
+      const stream = this._tokenStream;
+      let value = '';
+
+      while (stream.match([
+        Tokens.PLUS,
+        Tokens.MINUS,
+        Tokens.DIMENSION,
+        Tokens.NUMBER,
+        Tokens.STRING,
+        Tokens.IDENT,
+        Tokens.LENGTH,
+        Tokens.FREQ,
+        Tokens.ANGLE,
+        Tokens.TIME,
+        Tokens.RESOLUTION,
+        Tokens.SLASH,
+        list && Tokens.COMMA,
+      ])) {
+        value += stream._token.value;
+        value += this._ws();
+      }
+
+      return value.length ? value : null;
+    }
+
+    /*
+     * any
+     *   : ANY S* any_arg S* ')'
+     *   ;
+     */
+    _any() {
+      const stream = this._tokenStream;
+      if (!stream.match(Tokens.ANY)) return null;
+
+      const start = stream._token;
+      let value = stream._token.value + this._ws();
+
+      const arg = this._selectorsGroup();
+      value += arg + this._ws();
+
+      stream.match(Tokens.RPAREN);
+      value += stream._token.value;
+
+      const subpart = new SelectorSubPart(value, 'any', start);
+      subpart.args.push(arg);
+      return subpart;
+    }
+
+    /*
+     * negation
+     *   : NOT S* negation_arg S* ')'
+     *   ;
+     */
+    _negation() {
+      const stream = this._tokenStream;
+      if (!stream.match(Tokens.NOT)) return null;
+
+      const start = stream._token;
+      let value = stream._token.value + this._ws();
+
+      const arg = this._negationArg();
+      value += arg + this._ws();
+
+      stream.match(Tokens.RPAREN);
+      value += stream._token.value;
+
+      const subpart = new SelectorSubPart(value, 'not', start);
+      subpart.args.push(arg);
+      return subpart;
+    }
+
+    /*
+     * CSS3 allows only a single simple selector!
+     * negation_arg
+     *   : type_selector | universal | HASH | class | attrib | pseudo
+     *   ;
+     */
+    _negationArg() {
+      const stream = this._tokenStream;
+      const start = stream.LT(1);
+      const next = stream.peek();
+      const ns = this._namespacePrefix();
+      const arg =
+        this._typeSelector(ns) ||
+        this._universal(ns) ||
+        next === Tokens.HASH && this._hash() ||
+        next === Tokens.DOT && this._class() ||
+        next === Tokens.LBRACKET && this._attrib() ||
+        next === Tokens.COLON && this._pseudo();
+
+      if (!arg) this._unexpectedToken(stream.LT(1));
+
+      return arg.type === 'elementName' ?
+        new SelectorPart(arg, [], arg.toString(), start) :
+        new SelectorPart(null, [arg], arg.toString(), start);
+    }
+
+    /*
+     * declaration
+     *   : property ':' S* expr prio?
+     *   | /( empty )/
+     *   ;
+     */
+    _declaration(consumeSemicolon) {
+      const stream = this._tokenStream;
+
+      const property = this._property();
+      if (!property) {
+        return false;
+      }
+
+      stream.mustMatch(Tokens.COLON);
+
+      let value = null;
+      // whitespace is a part of custom property value
+      if (property.text.startsWith('--')) {
+        value = this._customProperty();
+      } else {
+        this._ws();
+        value = this._expr();
+      }
+
+      // if there's no parts for the value, it's an error
+      if (!value || value.length === 0) {
+        this._unexpectedToken(stream.LT(1));
+      }
+
+      const important = this._prio();
+
+      /*
+       * If hacks should be allowed, then only check the root
+       * property. If hacks should not be allowed, treat
+       * _property or *property as invalid properties.
+       */
+      let propertyName = property.toString();
+      if (this.options.starHack && property.hack === '*' ||
+          this.options.underscoreHack && property.hack === '_') {
+        propertyName = property.text;
+      }
+
+      let invalid = null;
+      try {
+        validateProperty(propertyName, value);
+      } catch (ex) {
+        invalid = ex;
+      }
+
+      const event = {
+        type: 'property',
+        property,
+        value,
+        important,
+      };
+      if (invalid) {
+        event.invalid = invalid;
+        event.message = invalid.message;
+      }
+      this.fire(event, property);
+
+      if (consumeSemicolon) stream.match(Tokens.SEMICOLON);
+      return true;
+    }
+
+    /*
+     * prio
+     *   : IMPORTANT_SYM S*
+     *   ;
+     */
+    _prio() {
+      const stream = this._tokenStream;
+      const result = stream.match(Tokens.IMPORTANT_SYM);
+
+      this._ws();
+      return result;
+    }
+
+    /*
+     * expr
+     *   : term [ operator term ]*
+     *   ;
+     */
+    _expr(inFunction) {
+      const stream = this._tokenStream;
+      const values = [];
+
+      while (true) {
+        let value = this._term(inFunction);
+        if (!value && !values.length) return null;
+
+        // get everything inside the parens and let validateProperty handle that
+        if (!value && inFunction && stream.peek() !== Tokens.RPAREN) {
+          stream.get();
+          value = new PropertyValuePart(stream._token);
+        } else if (!value) {
+          break;
+        }
+
+        // TODO: remove this hack
+        const last = values[values.length - 1];
+        if (last && last.offset === value.offset && last.text === value.text) {
+          break;
+        }
+
+        values.push(value);
+        this._ws();
+
+        const operator = this._operator(inFunction);
+        if (operator) values.push(operator);
+      }
+
+      return values[0] ? new PropertyValue(values, values[0]) : null;
+    }
+
+    _customProperty() {
+      const reader = this._tokenStream._reader;
+      const value = [];
+
+      // a custom property value may end before these characters
+      // that belong to the parent declaration, not to the custom property
+      let end = /[;!})]/;
+      const endings = [];
+
+      readValue:
+      while (!reader.eof()) {
+        const chunk = reader.readMatch(/([^;!'"{}()[\]/]|\/(?!\*))+/y);
+        if (chunk) {
+          value.push(chunk);
+        }
+
+        reader.mark();
+        const c = reader.read();
+        value.push(c);
+
+        switch (c) {
+          case '/':
+            value.push(reader.readMatch(/([^*]|\*(?!\/))*(\*\/|$)/y));
+            continue;
+          case '"':
+          case "'":
+            reader.reset();
+            value.pop();
+            value.push(this._tokenStream.readString());
+            continue;
+          case '{':
+            endings.push(end);
+            end = '}';
+            continue;
+          case '(':
+            endings.push(end);
+            end = ')';
+            continue;
+          case '[':
+            endings.push(end);
+            end = ']';
+            continue;
+          case ';':
+          case '!':
+            if (endings.length) {
+              continue;
+            }
+            reader.reset();
+          // fallthrough
+          case '}':
+          case ')':
+          case ']':
+            if (end instanceof RegExp ? !end.test(c) : c !== end) {
+              reader.reset();
+              return null;
+            }
+            end = endings.pop();
+            if (end) {
+              continue;
+            }
+            if (c === '}' || c === ')') {
+              // unget parent }
+              reader.reset();
+              value.pop();
+            }
+            break readValue;
+        }
+      }
+      if (!value[0]) return null;
+      const token = this._tokenStream._token;
+      token.value = value.join('');
+      token.type = Tokens.CUSTOM_PROP;
+      return new PropertyValue([new PropertyValuePart(token)], token);
+    }
+
+    /*
+     * term
+     *   : unary_operator?
+     *     [ NUMBER S* | PERCENTAGE S* | LENGTH S* | ANGLE S* |
+     *       TIME S* | FREQ S* | function | ie_function ]
+     *   | STRING S* | IDENT S* | URI S* | UNICODERANGE S* | hexcolor
+     *   ;
+     */
+    _term(inFunction) {
+      const stream = this._tokenStream;
+
+      const unary = this._unaryOperator() && stream._token;
+
+      const finalize = (token, value) => {
+        if (!token) return null;
+        if (token instanceof SyntaxUnit) return token;
+        if (unary) {
+          token.startLine = unary.startLine;
+          token.startCol = unary.startCol;
+          token.value = unary.value + (value || token.value);
+        } else if (value) {
+          token.value = value;
+        }
+        return new PropertyValuePart(token);
+      };
+
+      // exception for IE filters
+      if (stream.peek() === Tokens.IE_FUNCTION && this.options.ieFilters) {
+        return finalize(this._ieFunction());
+      }
+
+      // see if it's a simple block
+      if (inFunction && stream.match([Tokens.LPAREN, Tokens.LBRACE, Tokens.LBRACKET])) {
+        const token = stream._token;
+        const value = token.value + this._expr(inFunction).text + token.endChar;
+        stream.mustMatch(Tokens.type(token.endChar));
+        return finalize(token, value);
+      }
+
+      return finalize(
+        // see if there's a simple match
+        stream.match([
+          Tokens.NUMBER,
+          Tokens.PERCENTAGE,
+          Tokens.LENGTH,
+          Tokens.ANGLE,
+          Tokens.TIME,
+          Tokens.DIMENSION,
+          Tokens.FREQ,
+          Tokens.STRING,
+          inFunction === 'var' && Tokens.CUSTOM_PROP,
+          Tokens.IDENT,
+          Tokens.URI,
+          Tokens.UNICODE_RANGE,
+          Tokens.USO_VAR,
+        ]) && stream._token ||
+        this._hexcolor() ||
+        this._function({asText: unary}));
+    }
+
+    /*
+     * function
+     *   : FUNCTION S* expr ')' S*
+     *   ;
+     */
+    _function({asText} = {}) {
+      const stream = this._tokenStream;
+      if (!stream.match(Tokens.FUNCTION)) return null;
+      this._ws();
+
+      const start = stream._token;
+      const name = start.value.slice(0, -1);
+      const expr = this._expr(lower(name)) || '';
+      const ieFilter = this.options.ieFilters && stream.peek() === Tokens.EQUALS ?
+        this._functionIeFilter() : '';
+      const text = name + '(' + expr + ieFilter + ')';
+
+      stream.mustMatch(Tokens.RPAREN);
+      this._ws();
+
+      if (asText) return text;
+
+      const unit = new SyntaxUnit(text, start, 'function');
+      unit.expr = expr;
+      unit.name = name;
+      unit.tokenType = Tokens.FUNCTION;
+      return unit;
+    }
+
+    _functionIeFilter() {
+      const stream = this._tokenStream;
+      const text = [];
+
+      do {
+        if (this._ws()) {
+          text.push(stream._token.value);
+        }
+
+        // might be second time in the loop
+        if (stream.LA(0) === Tokens.COMMA) {
+          text.push(stream._token.value);
+        }
+
+        stream.match(Tokens.IDENT);
+        text.push(stream._token.value);
+
+        stream.match(Tokens.EQUALS);
+        text.push(stream._token.value);
+
+        let lt = stream.peek();
+        while (lt !== Tokens.COMMA &&
+               lt !== Tokens.S &&
+               lt !== Tokens.RPAREN &&
+               lt !== Tokens.EOF) {
+          stream.get();
+          text.push(stream._token.value);
+          lt = stream.peek();
+        }
+      } while (stream.match([Tokens.COMMA, Tokens.S]));
+
+      return text.join('');
+    }
+
+    /* (My own extension)
+     * ie_function
+     *   : IE_FUNCTION S* IDENT '=' term [S* ','? IDENT '=' term]+ ')' S*
+     *   ;
+     */
+    _ieFunction() {
+      const stream = this._tokenStream;
+      let functionText = null;
+      let lt;
+
+      // IE function can begin like a regular function, too
+      if (stream.match([Tokens.IE_FUNCTION, Tokens.FUNCTION])) {
+        functionText = stream._token.value;
+
+        do {
+
+          if (this._ws()) {
+            functionText += stream._token.value;
+          }
+
+          // might be second time in the loop
+          if (stream.LA(0) === Tokens.COMMA) {
+            functionText += stream._token.value;
+          }
+
+          stream.match(Tokens.IDENT);
+          functionText += stream._token.value;
+
+          stream.match(Tokens.EQUALS);
+          functionText += stream._token.value;
+
+          // functionText += this._term();
+          lt = stream.peek();
+          while (lt !== Tokens.COMMA && lt !== Tokens.S && lt !== Tokens.RPAREN) {
+            stream.get();
+            functionText += stream._token.value;
+            lt = stream.peek();
+          }
+        } while (stream.match([Tokens.COMMA, Tokens.S]));
+
+        stream.match(Tokens.RPAREN);
+        functionText += ')';
+        this._ws();
+      }
+
+      return functionText;
+    }
+
+    /*
+     * There is a constraint on the color that it must
+     * have either 3,4 or 6,8 hex-digits (i.e., [0-9a-fA-F])
+     * after the "#"; e.g., "#000" is OK, but "#abcd" is not.
+     *
+     * hexcolor
+     *   : HASH S*
+     *   ;
+     */
+    _hexcolor() {
+      const stream = this._tokenStream;
+
+      if (!stream.match(Tokens.HASH)) return null;
+
+      const token = stream._token;
+      const color = token.value;
+      const len = color.length;
+
+      if (len !== 4 && len !== 5 && len !== 7 && len !== 9 ||
+          !/^#([a-f\d]{3}(?:[a-f\d](?:[a-f\d]{2}){0,2})?)$/i.test(color)) {
+        const {startLine, startCol} = token;
+        throw new SyntaxError(
+          `Expected a hex color but found '${color}' at line ${startLine}, col ${startCol}.`,
+          {startLine, startCol});
+      }
+
+      this._ws();
+      return token;
+    }
+
+    //-----------------------------------------------------------------
+    // Animations methods
+    //-----------------------------------------------------------------
+
+    /*
+     * keyframes:
+     *   : KEYFRAMES_SYM S* keyframe_name S* '{' S* keyframe_rule* '}' {
+     *   ;
+     */
+    _keyframes() {
+      const stream = this._tokenStream;
+      let prefix = '';
+
+      stream.mustMatch(Tokens.KEYFRAMES_SYM);
+      const token = stream._token;
+      if (/^@-([^-]+)-/.test(token.value)) prefix = RegExp.$1;
+
+      this._ws();
+      const name = this._keyframeName();
+
+      this._ws();
+      stream.mustMatch(Tokens.LBRACE);
+
+      this.fire({
+        type: 'startkeyframes',
+        name,
+        prefix,
+      }, token);
+
+      // check for key
+      while (true) {
+        this._ws();
+        const tt = stream.peek();
+        if (tt !== Tokens.IDENT && tt !== Tokens.PERCENTAGE) break;
+        this._keyframeRule();
+      }
+
+      stream.mustMatch(Tokens.RBRACE);
+
+      this.fire({
+        type: 'endkeyframes',
+        name,
+        prefix,
+      });
+
+      this._ws();
+    }
+
+    /*
+     * keyframe_name:
+     *   : IDENT
+     *   | STRING
+     *   ;
+     */
+    _keyframeName() {
+      const stream = this._tokenStream;
+      stream.mustMatch([Tokens.IDENT, Tokens.STRING]);
+      return SyntaxUnit.fromToken(stream._token);
+    }
+
+    /*
+     * keyframe_rule:
+     *   : key_list S*
+     *     '{' S* declaration [ ';' S* declaration ]* '}' S*
+     *   ;
+     */
+    _keyframeRule() {
+      const keyList = this._keyList();
+
+      this.fire({
+        type: 'startkeyframerule',
+        keys: keyList,
+      }, keyList[0]);
+
+      this._readDeclarations();
+
+      this.fire({
+        type: 'endkeyframerule',
+        keys: keyList,
+      });
+    }
+
+    /*
+     * key_list:
+     *   : key [ S* ',' S* key]*
+     *   ;
+     */
+    _keyList() {
+      const stream = this._tokenStream;
+      const keyList = [];
+
+      // must be least one key
+      keyList.push(this._key());
+
+      this._ws();
+
+      while (stream.match(Tokens.COMMA)) {
+        this._ws();
+        keyList.push(this._key());
+        this._ws();
+      }
+
+      return keyList;
+    }
+
+    /*
+     * There is a restriction that IDENT can be only "from" or "to".
+     *
+     * key
+     *   : PERCENTAGE
+     *   | IDENT
+     *   ;
+     */
+    _key() {
+      const stream = this._tokenStream;
+      let token;
+
+      if (stream.match(Tokens.PERCENTAGE)) {
+        return SyntaxUnit.fromToken(stream._token);
+      } else if (stream.match(Tokens.IDENT)) {
+        token = stream._token;
+
+        if (/from|to/i.test(token.value)) {
+          return SyntaxUnit.fromToken(token);
+        }
+
+        stream.unget();
+      }
+
+      // if it gets here, there wasn't a valid token, so time to explode
+      this._unexpectedToken(stream.LT(1));
+    }
+
+    //-----------------------------------------------------------------
+    // Helper methods
+    //-----------------------------------------------------------------
+
+    /**
+     * Not part of CSS grammar, but useful for skipping over
+     * combination of white space and HTML-style comments.
+     */
+    _skipCruft() {
+      while (this._tokenStream.match([
+        Tokens.S,
+        Tokens.CDO,
+        Tokens.CDC,
+      ])) { /*NOP*/ }
+    }
+
+    /**
+     * Not part of CSS grammar, but this pattern occurs frequently
+     * in the official CSS grammar. Split out here to eliminate
+     * duplicate code.
+     * @param {Boolean} checkStart Indicates if the rule should check
+     *      for the left brace at the beginning.
+     * @param {Boolean} readMargins Indicates if the rule should check
+     *      for margin patterns.
+     *
+     * Reads the pattern
+     * S* '{' S* declaration [ ';' S* declaration ]* '}' S*
+     * or
+     * S* '{' S* [ declaration | margin ]? [ ';' S* [ declaration | margin ]? ]* '}' S*
+     * Note that this is how it is described in CSS3 Paged Media, but is actually incorrect.
+     * A semicolon is only necessary following a declaration if there's another declaration
+     * or margin afterwards.
+     */
+    _readDeclarations({
+      checkStart = true,
+      readMargins = false,
+      stopAfterBrace = false
+    } = {}) {
+      const stream = this._tokenStream;
+
+      if (checkStart) {
+        this._ws();
+        stream.mustMatch(Tokens.LBRACE);
+      }
+
+      try {
+        while (stream.peek() !== Tokens.RBRACE) {
+          this._ws();
+          if (stream.match(Tokens.SEMICOLON) || readMargins && this._margin()) continue;
+          if (!this._declaration(true)) break;
+        }
+        stream.mustMatch(Tokens.RBRACE);
+        if (!stopAfterBrace) this._ws();
+        return;
+
+      } catch (ex) {
+
+        // if not a syntax error, rethrow it
+        if (!(ex instanceof SyntaxError) || this.options.strict) throw ex;
+
+        this.fire(Object.assign({}, ex, {type: 'error', error: ex}));
+
+        switch (stream.advance([Tokens.SEMICOLON, Tokens.RBRACE])) {
+          case Tokens.SEMICOLON:
+            // see if there's another declaration
+            this._readDeclarations({checkStart: false, readMargins, stopAfterBrace});
+            return;
+          case Tokens.RBRACE:
+            // the rule is finished
+            return;
+          default:
+            // rethrow the error because it wasn't handled properly
+            throw ex;
+        }
+      }
+    }
+
+    /**
+     * In some cases, you can end up with two white space tokens in a
+     * row. Instead of making a change in every function that looks for
+     * white space, this function is used to match as much white space
+     * as necessary.
+     * @return {String} The white space if found, empty string if not.
+     */
+    _ws() {
+      let ws = '';
+      const stream = this._tokenStream;
+      while (stream.match(Tokens.S)) {
+        ws += stream._token.value;
+      }
+      return ws;
+    }
+
+    /**
+     * Throws an error when an unexpected token is found.
+     * @param {Object} token The token that was found.
+     */
+    _unexpectedToken(token) {
+      const {value, startLine: line, startCol: col} = token;
+      throw new SyntaxError(`Unexpected token '${value}' at line ${line}, col ${col}.`, token);
+    }
+
+    /**
+     * Helper method used for parsing subparts of a style sheet.
+     */
+    _verifyEnd() {
+      if (this._tokenStream.LA(1) !== Tokens.EOF) {
+        this._unexpectedToken(this._tokenStream.LT(1));
+      }
+    }
+
+    //-----------------------------------------------------------------
+    // Parsing methods
+    //-----------------------------------------------------------------
+
+    parse(input, {reuseCache} = {}) {
+      this._tokenStream = new TokenStream(input);
+      parserCache.start(reuseCache && this);
+      this._stylesheet();
+    }
+
+    parseStyleSheet(input) {
+      // just passthrough
+      return this.parse(input);
+    }
+
+    parseMediaQuery(input, {reuseCache} = {}) {
+      this._tokenStream = new TokenStream(input);
+      parserCache.start(reuseCache && this);
+      const result = this._mediaQuery();
+      this._verifyEnd();
+      return result;
+    }
+
+    /**
+     * Parses a property value (everything after the semicolon).
+     * @return {parserlib.css.PropertyValue} The property value.
+     * @throws parserlib.util.SyntaxError If an unexpected token is found.
+     */
+    parsePropertyValue(input) {
+      this._tokenStream = new TokenStream(input);
+      this._ws();
+      const result = this._expr();
+      this._ws();
+      this._verifyEnd();
+      return result;
+    }
+
+    /**
+     * Parses a complete CSS rule, including selectors and
+     * properties.
+     * @param {String} input The text to parser.
+     * @return {Boolean} True if the parse completed successfully, false if not.
+     */
+    parseRule(input, {reuseCache} = {}) {
+      this._tokenStream = new TokenStream(input);
+      parserCache.start(reuseCache && this);
+      this._ws();
+      const result = this._ruleset();
+      this._ws();
+      this._verifyEnd();
+      return result;
+    }
+
+    /**
+     * Parses a single CSS selector (no comma)
+     * @param {String} input The text to parse as a CSS selector.
+     * @return {Selector} An object representing the selector.
+     * @throws parserlib.util.SyntaxError If an unexpected token is found.
+     */
+    parseSelector(input) {
+      this._tokenStream = new TokenStream(input);
+      this._ws();
+      const result = this._selector();
+      this._ws();
+      this._verifyEnd();
+      return result;
+    }
+
+    /**
+     * Parses an HTML style attribute: a set of CSS declarations
+     * separated by semicolons.
+     * @param {String} input The text to parse as a style attribute
+     * @return {void}
+     */
+    parseStyleAttribute(input) {
+      // help error recovery in _readDeclarations()
+      this._tokenStream = new TokenStream(input + '}');
+      this._readDeclarations({checkStart: false});
+    }
+  }
+
+  Object.assign(Parser, TYPES);
+  Object.assign(Parser.prototype, TYPES);
+  Parser.prototype._readWhitespace = Parser.prototype._ws;
+
+  //endregion
+  //region PUBLIC API
+
+  return {
+    css: {
+      Colors,
+      Combinator,
+      Parser,
+      PropertyName,
+      PropertyValue,
+      PropertyValuePart,
+      Matcher,
+      MediaFeature,
+      MediaQuery,
+      Selector,
+      SelectorPart,
+      SelectorSubPart,
+      Specificity,
+      TokenStream,
+      Tokens,
+      ValidationError,
+    },
+    util: {
+      StringReader,
+      SyntaxError,
+      SyntaxUnit,
+      EventTarget,
+      TokenStreamBase,
+    },
+    cache: parserCache,
+  };
+
+  //endregion
+})();