diff --git a/_locales/en/messages.json b/_locales/en/messages.json
index c1a7b3b9..c1afc23a 100644
--- a/_locales/en/messages.json
+++ b/_locales/en/messages.json
@@ -739,9 +739,9 @@
     "message": "Search contents",
     "description": "Label for the search filter textbox on the Manage styles page"
   },
-  "searchStylesTooltip": {
-    "message": "To show styles for a URL, prefix it with 'url:'\nFor example, url:https://github.com/openstyles/stylus",
-    "description": "Label for the search filter textbox on the Manage styles page"
+  "searchStylesHelp": {
+    "message": "</> key focuses the search field.\nPlain text: search within the name, code, homepage URL and sites it is applied to. Words with less than 3 letters are ignored.\nMatching URL: prefix the search with <url:>, e.g. <url:https://github.com/openstyles/stylus>\nRegular expressions: include slashes and flags, e.g. </body.*?\\ba\\b/simguy>\nExact words: wrap the query in double quotes, e.g. <\".header ~ div\">",
+    "description": "Text in the minihelp displayed when clicking (i) icon to the right of the search input field on the Manage styles page"
   },
   "sectionAdd": {
     "message": "Add another section",
diff --git a/edit.html b/edit.html
index 7efc20ce..a1a712ce 100644
--- a/edit.html
+++ b/edit.html
@@ -74,7 +74,7 @@
     <link rel="stylesheet" href="/edit/codemirror-default.css">
 
     <template data-id="appliesTo">
-      <li>
+      <li class="applies-to-item">
         <div class="select-resizer">
           <select name="applies-type" class="applies-type style-contributor">
             <option value="url" i18n-text="appliesUrlOption"></option>
@@ -322,7 +322,7 @@
       <h2><span id="sections-heading" i18n-text="styleSectionsTitle"></span><svg id="sections-help" class="svg-icon info"><use xlink:href="#svg-icon-help"/></svg></h2>
     </section>
     <div id="help-popup">
-      <div class="title"></div><svg id="sections-help" class="svg-icon dismiss"><use xlink:href="#svg-icon-close"/></svg></svg>
+      <div class="title"></div><svg id="sections-help" class="svg-icon dismiss"><use xlink:href="#svg-icon-close"/></svg>
       <div class="contents"></div>
     </div>
 
diff --git a/edit/applies-to-line-widget.js b/edit/applies-to-line-widget.js
index 91d26f63..5fcccb0d 100644
--- a/edit/applies-to-line-widget.js
+++ b/edit/applies-to-line-widget.js
@@ -5,7 +5,7 @@ function createAppliesToLineWidget(cm) {
   const THROTTLE_DELAY = 400;
   let TPL, EVENTS, CLICK_ROUTE;
   let widgets = [];
-  let fromLine, toLine, styleVariables;
+  let fromLine, toLine, actualStyle;
   let initialized = false;
   return {toggle};
 
@@ -29,28 +29,16 @@ function createAppliesToLineWidget(cm) {
           $create('label', t('appliesLabel')),
           $create('ul.applies-to-list'),
         ]),
-      listItem:
-        $create('li.applies-to-item', [
-          $create('select.applies-type', [
-            $create('option', {value: 'url'}, t('appliesUrlOption')),
-            $create('option', {value: 'url-prefix'}, t('appliesUrlPrefixOption')),
-            $create('option', {value: 'domain'}, t('appliesDomainOption')),
-            $create('option', {value: 'regexp'}, t('appliesRegexpOption')),
-          ]),
-          $create('input.applies-value', {spellcheck: false}),
-          $create('button.test-regexp', t('styleRegexpTestButton')),
-          $create('button.remove-applies-to', t('appliesRemove')),
-          $create('button.add-applies-to', t('appliesAdd')),
-        ]),
+      listItem: template.appliesTo,
       appliesToEverything:
         $create('li.applies-to-everything', t('appliesToEverything')),
     };
 
+    $('button', TPL.listItem).insertAdjacentElement('beforebegin',
+      $create('button.test-regexp', t('styleRegexpTestButton')));
+
     CLICK_ROUTE = {
-      '.test-regexp': (item, apply) => {
-        regExpTester.toggle();
-        regExpTester.update([apply.value.text]);
-      },
+      '.test-regexp': showRegExpTester,
 
       '.remove-applies-to': (item, apply) => {
         const applies = item.closest('.applies-to').__applies;
@@ -108,20 +96,17 @@ function createAppliesToLineWidget(cm) {
         if (typeElement) {
           const item = target.closest('.applies-to-item');
           const apply = item.__apply;
-          changeItem(apply, 'type', typeElement.value);
+          changeItem(item, apply, 'type', typeElement.value);
           item.dataset.type = apply.type.text;
+        } else {
+          return EVENTS.oninput.apply(this, arguments);
         }
       },
       oninput({target}) {
         if (target.matches('.applies-value')) {
-          const apply = target.closest('.applies-to-item').__apply;
-          debounce(changeItem, THROTTLE_DELAY, apply, 'value', target.value);
-        }
-      },
-      onfocus({target}) {
-        if (target.matches('.test-regexp')) {
-          const apply = target.closest('.applies-to-item').__apply;
-          updateRegexpTest(apply);
+          const item = target.closest('.applies-to-item');
+          const apply = item.__apply;
+          changeItem(item, apply, 'value', target.value);
         }
       },
       onclick({target}) {
@@ -136,15 +121,13 @@ function createAppliesToLineWidget(cm) {
       }
     };
 
-    styleVariables = $create('style');
+    actualStyle = $create('style');
     fromLine = 0;
     toLine = cm.doc.size;
 
     cm.on('change', onChange);
     cm.on('optionChange', onOptionChange);
 
-    // is it possible to avoid flickering?
-    window.addEventListener('load', updateWidgetStyle);
     chrome.runtime.onMessage.addListener(onRuntimeMessage);
 
     updateWidgetStyle();
@@ -158,9 +141,8 @@ function createAppliesToLineWidget(cm) {
     widgets.length = 0;
     cm.off('change', onChange);
     cm.off('optionChange', onOptionChange);
-    window.removeEventListener('load', updateWidgetStyle);
     chrome.runtime.onMessage.removeListener(onRuntimeMessage);
-    styleVariables.remove();
+    actualStyle.remove();
   }
 
   function onChange(cm, event) {
@@ -229,24 +211,112 @@ function createAppliesToLineWidget(cm) {
   }
 
   function updateWidgetStyle() {
-    const gutterStyle = getComputedStyle(cm.getGutterElement());
-    const borderStyle = gutterStyle.borderRightWidth !== '0px' ?
-      `${gutterStyle.borderRightWidth} ${gutterStyle.borderRightStyle} ${gutterStyle.borderRightColor}` :
-      `1px solid ${gutterStyle.color}`;
-    const id = Date.now();
-    styleVariables.textContent = `
-      .single-editor {
-        --at-background-color-${id}: ${gutterStyle.backgroundColor};
-        --at-border-top-${id}: ${borderStyle};
-        --at-border-bottom-${id}: ${borderStyle};
-      }
+    const MIN_LUMA = .05;
+    const MIN_LUMA_DIFF = .4;
+    const color = {
+      wrapper: getRealColors(cm.display.wrapper),
+      gutter: getRealColors(cm.display.gutters, {
+        bg: 'backgroundColor',
+        border: 'borderRightColor',
+      }),
+      line: getRealColors('.CodeMirror-linenumber'),
+      comment: getRealColors('span.cm-comment'),
+    };
+    const hasBorder =
+      color.gutter.style.borderRightWidth !== '0px' &&
+      !/transparent|\b0\)/g.test(color.gutter.style.borderRightColor);
+    const diff = {
+      wrapper: Math.abs(color.gutter.bgLuma - color.wrapper.foreLuma),
+      border: hasBorder ? Math.abs(color.gutter.bgLuma - color.gutter.borderLuma) : 0,
+      line: Math.abs(color.gutter.bgLuma - color.line.foreLuma),
+    };
+    const preferLine = diff.line > diff.wrapper || diff.line > MIN_LUMA_DIFF;
+    const fore = preferLine ? color.line.fore : color.wrapper.fore;
+
+    const border = fore.replace(/[\d.]+(?=\))/, MIN_LUMA_DIFF / 2);
+    const borderStyleForced = `1px ${hasBorder ? color.gutter.style.borderRightStyle : 'solid'} ${border}`;
+
+    actualStyle.textContent = `
       .applies-to {
-        background-color: var(--at-background-color-${id});
-        border-top: var(--at-border-top-${id});
-        border-bottom: var(--at-border-bottom-${id});
+        background-color: ${color.gutter.bg};
+        border-top: ${borderStyleForced};
+        border-bottom: ${borderStyleForced};
+      }
+      .applies-to label {
+        color: ${fore};
+      }
+      .applies-to input,
+      .applies-to select {
+        background-color: rgba(255, 255, 255, ${
+          Math.max(MIN_LUMA, Math.pow(Math.max(0, color.gutter.bgLuma - MIN_LUMA * 2), 2)).toFixed(2)
+        });
+        border: ${borderStyleForced};
+        transition: none;
+        color: ${fore};
+      }
+      .applies-to .svg-icon.select-arrow {
+        fill: ${fore};
+        transition: none;
       }
     `;
-    document.documentElement.appendChild(styleVariables);
+    document.documentElement.appendChild(actualStyle);
+
+    function getRealColors(el, targets = {}) {
+      targets.fore = 'color';
+      const colors = {};
+      const done = {};
+      let numDone = 0;
+      let numTotal = 0;
+      for (const k in targets) {
+        colors[k] = {r: 255, g: 255, b: 255, a: 1};
+        numTotal++;
+      }
+      const isDummy = typeof el === 'string';
+      el = isDummy ? cm.display.lineDiv.appendChild($create(el, {style: 'display: none'})) : el;
+      for (let current = el; current; current = current && current.parentElement) {
+        const style = getComputedStyle(current);
+        for (const k in targets) {
+          if (!done[k]) {
+            done[k] = blend(colors[k], style[targets[k]]);
+            numDone += done[k] ? 1 : 0;
+            if (numDone === numTotal) {
+              current = null;
+              break;
+            }
+          }
+        }
+        colors.style = colors.style || style;
+      }
+      if (isDummy) {
+        el.remove();
+      }
+      for (const k in targets) {
+        const {r, g, b, a} = colors[k];
+        colors[k] = `rgba(${r}, ${g}, ${b}, ${a})`;
+        // https://www.w3.org/TR/AERT#color-contrast
+        colors[k + 'Luma'] = (r * .299 + g * .587 + b * .114) / 256;
+      }
+      return colors;
+    }
+
+    function blend(base, color) {
+      const [r, g, b, a = 255] = (color.match(/\d+/g) || []).map(Number);
+      if (a === 255) {
+        base.r = r;
+        base.g = g;
+        base.b = b;
+        base.a = 1;
+      } else if (a) {
+        const mixedA = 1 - (1 - a / 255) * (1 - base.a);
+        const q1 = a / 255 / mixedA;
+        const q2 = base.a * (1 - mixedA) / mixedA;
+        base.r = Math.round(r * q1 + base.r * q2);
+        base.g = Math.round(g * q1 + base.g * q2);
+        base.b = Math.round(b * q1 + base.b * q2);
+        base.a = mixedA;
+      }
+      return Math.abs(base.a - 1) < 1e-3;
+    }
   }
 
   function doUpdate() {
@@ -406,14 +476,14 @@ function createAppliesToLineWidget(cm) {
     return el;
   }
 
-  function changeItem(apply, part, newText) {
+  function changeItem(itemElement, apply, part, newText) {
     if (!apply) {
       return;
     }
     part = apply[part];
     const range = part.mark.find();
     part.mark.clear();
-    newText = newText.replace(/\\/g, '\\\\');
+    newText = unescapeDoubleslash(newText).replace(/\\/g, '\\\\');
     cm.replaceRange(newText, range.from, range.to, 'appliesTo');
     part.mark = cm.markText(
       range.from,
@@ -432,13 +502,8 @@ function createAppliesToLineWidget(cm) {
       );
     }
 
-    updateRegexpTest(apply);
-  }
-
-  function updateRegexpTest(apply) {
-    if (apply.type.text === 'regexp') {
-      const rx = apply.value.text.trim();
-      regExpTester.update(rx ? [rx] : {});
+    if (apply.type.text === 'regexp' && apply.value.text.trim()) {
+      showRegExpTester(itemElement);
     }
   }
 
@@ -450,7 +515,6 @@ function createAppliesToLineWidget(cm) {
     const valueStart = typeEnd + 1 + Number(isQuoted);
     const valueEnd = valueStart + valueText.length;
     const end = valueEnd + Number(isQuoted) + 1;
-    const hasSingleEscapes = /([^\\]|^)\\([^\\]|$)/.test(valueText);
     return {
       start,
       type: {
@@ -459,7 +523,7 @@ function createAppliesToLineWidget(cm) {
         end: typeEnd,
       },
       value: {
-        text: hasSingleEscapes ? valueText : valueText.replace(/\\\\/g, '\\'),
+        text: unescapeDoubleslash(valueText),
         start: valueStart,
         end: valueEnd,
       },
@@ -505,4 +569,17 @@ function createAppliesToLineWidget(cm) {
     const first = s.charAt(0);
     return (first === '"' || first === "'") && s.endsWith(first) ? s.slice(1, -1) : s;
   }
+
+  function unescapeDoubleslash(s) {
+    const hasSingleEscapes = /([^\\]|^)\\([^\\]|$)/.test(s);
+    return hasSingleEscapes ? s : s.replace(/\\\\/g, '\\');
+  }
+
+  function showRegExpTester(item) {
+    regExpTester.toggle(true);
+    regExpTester.update(
+      item.closest('.applies-to').__applies
+        .filter(a => a.type.text === 'regexp')
+        .map(a => unescapeDoubleslash(a.value.text)));
+  }
 }
diff --git a/edit/codemirror-default.css b/edit/codemirror-default.css
index 72370f4c..66ef1966 100644
--- a/edit/codemirror-default.css
+++ b/edit/codemirror-default.css
@@ -56,7 +56,3 @@
   position: absolute;
   pointer-events: none;
 }
-
-.CodeMirror-activeline .applies-to ul {
-  z-index: 2;
-}
diff --git a/edit/codemirror-default.js b/edit/codemirror-default.js
index f2c2c452..e68d9f35 100644
--- a/edit/codemirror-default.js
+++ b/edit/codemirror-default.js
@@ -193,7 +193,8 @@ CodeMirror.hint && (() => {
         string[pos - 3] === ']' &&
         string[pos - 4] === ']') {
       const vars = typeof editor !== 'undefined' && (editor.getStyle().usercssData || {}).vars;
-      if (vars && Object.hasOwnProperty.call(vars, string.slice(start + 4, pos - 4))) {
+      const name = vars && string.slice(start + 4, pos - 4);
+      if (vars && Object.hasOwnProperty.call(vars, name.endsWith('-rgb') ? name.slice(0, -4) : name)) {
         token[0] = USO_VALID_VAR;
       } else {
         token[0] = USO_INVALID_VAR;
diff --git a/edit/edit.css b/edit/edit.css
index eadba48e..11c1c08b 100644
--- a/edit/edit.css
+++ b/edit/edit.css
@@ -331,11 +331,11 @@ body[data-match-highlight="selection"] .CodeMirror-selection-highlight-scrollbar
   min-height: 1.4rem;
   margin-left: 0.35rem;
 }
-.applies-to li .add-applies-to {
+html:not(.usercss) .applies-to li .add-applies-to {
   visibility: hidden;
   text-align: left;
 }
-.applies-to li:last-child .add-applies-to {
+html:not(.usercss) .applies-to li:last-child .add-applies-to {
   visibility: visible
 }
 .applies-to li .add-applies-to:first-child {
@@ -404,6 +404,12 @@ body[data-match-highlight="selection"] .CodeMirror-selection-highlight-scrollbar
   margin-left: -20px;
   margin-top: -1px;
 }
+.regexp-report-note {
+  color: #999;
+  position: absolute;
+  margin: 0 0.5rem 0 0;
+  hyphens: auto;
+}
 /************ help popup ************/
 #help-popup {
   top: 3rem;
@@ -646,8 +652,8 @@ html:not(.usercss) .usercss-only,
   margin-top: 0.35rem;
 }
 
-.CodeMirror-linewidget .applies-to li:not([data-type="regexp"]) .applies-to-regexp-test {
-  display: none;
+.CodeMirror-linewidget .applies-to li[data-type="regexp"] .test-regexp {
+  display: inline;
 }
 
 .CodeMirror-linewidget li.applies-to-everything {
diff --git a/edit/regexp-tester.js b/edit/regexp-tester.js
index 4c5e63ff..8da9854c 100644
--- a/edit/regexp-tester.js
+++ b/edit/regexp-tester.js
@@ -160,13 +160,15 @@ var regExpTester = (() => {
           }
         }
       }
-      report.appendChild(
-        $create('p.regexp-report-note',
-          t('styleRegexpTestNote')
-            .split(/(\\+)/)
-            .map(s => (s.startsWith('\\') ? $create('code', s) : s))));
       showHelp(t('styleRegexpTestTitle'), report);
 
+      const note = $create('p.regexp-report-note',
+        t('styleRegexpTestNote')
+          .split(/(\\+)/)
+          .map(s => (s.startsWith('\\') ? $create('code', s) : s)));
+      report.appendChild(note);
+      report.style.paddingBottom = note.offsetHeight + 'px';
+
       report.onclick = event => {
         const target = event.target.closest('a, .regexp-report div');
         if (target) {
diff --git a/global.css b/global.css
index a7910669..28b69ed1 100644
--- a/global.css
+++ b/global.css
@@ -42,6 +42,19 @@ input[type="checkbox"]:not(.slider):checked + .svg-icon.checked {
   pointer-events: none;
 }
 
+input[type="checkbox"]:not(.slider):disabled {
+  background-color: transparent;
+  border-color: hsl(0, 0%, 50%);
+}
+
+input[type="checkbox"]:not(.slider):disabled + .svg-icon.checked {
+  fill: hsl(0, 0%, 50%);
+}
+
+input[type="checkbox"]:not(.slider):disabled + .svg-icon.checked + span {
+  color: hsl(0, 0%, 50%);
+}
+
 label {
   transition: color .1s;
 }
@@ -50,6 +63,7 @@ select {
   -moz-appearance: none;
   -webkit-appearance: none;
   height: 22px;
+  color: currentColor;
   background-color: transparent;
   border: 1px solid hsl(0, 0%, 66%);
   padding: 0 20px 0 6px;
@@ -72,7 +86,7 @@ select {
   display: inline-flex;
   height: 14px;
   width: 14px;
-  fill: #000;
+  fill: currentColor;
   position: absolute;
   top: 4px;
   right: 4px;
@@ -92,4 +106,12 @@ select {
     padding-left: .75ex;
     padding-right: .75ex;
   }
+
+  ::-moz-focus-inner { 
+    border: 0; 
+  }
+
+  svg {
+    transform: scale(1); /* de-blur */
+  }
 }
diff --git a/install-usercss/install-usercss.js b/install-usercss/install-usercss.js
index 3d347955..0d69222b 100644
--- a/install-usercss/install-usercss.js
+++ b/install-usercss/install-usercss.js
@@ -276,7 +276,7 @@
           data.version,
         ]))
       ).then(ok => ok &&
-        BG.usercssHelper.save(BG.deepCopy(Object.assign(style, {reason: 'update'})))
+        BG.usercssHelper.save(BG.deepCopy(Object.assign(style, dup && {reason: 'update'})))
           .then(r => install(deepCopy(r)))
           .catch(err => messageBox.alert(t('styleInstallFailed', err)))
       );
diff --git a/js/messaging.js b/js/messaging.js
index 47c8900b..0936870c 100644
--- a/js/messaging.js
+++ b/js/messaging.js
@@ -286,9 +286,9 @@ function tryCatch(func, ...args) {
 }
 
 
-function tryRegExp(regexp) {
+function tryRegExp(regexp, flags) {
   try {
-    return new RegExp(regexp);
+    return new RegExp(regexp, flags);
   } catch (e) {}
 }
 
diff --git a/js/prefs.js b/js/prefs.js
index 70444b15..4eb5b0db 100644
--- a/js/prefs.js
+++ b/js/prefs.js
@@ -24,6 +24,8 @@ var prefs = new function Prefs() {
     'manage.onlyLocal.invert': false,   // display only externally installed styles
     'manage.onlyUsercss.invert': false, // display only non-usercss (standard) styles
     // UI element state: expanded/collapsed
+    'manage.backup.expanded': true,
+    'manage.filters.expanded': true,
     'manage.options.expanded': true,
     // the new compact layout doesn't look good on Android yet
     'manage.newUI': !navigator.appVersion.includes('Android'),
diff --git a/js/usercss.js b/js/usercss.js
index b3a8a07d..4800221d 100644
--- a/js/usercss.js
+++ b/js/usercss.js
@@ -393,6 +393,7 @@ var usercss = (() => {
     };
 
     const style = {
+      reason: 'install',
       enabled: true,
       sourceCode,
       sections: [],
diff --git a/manage.html b/manage.html
index d9340425..d9fa2f40 100644
--- a/manage.html
+++ b/manage.html
@@ -6,6 +6,7 @@
   <title i18n-text="manageTitle"></title>
   <link rel="stylesheet" href="global.css">
   <link rel="stylesheet" href="manage/manage.css">
+  <link rel="stylesheet" href="manage/config-dialog.css">
   <link rel="stylesheet" href="msgbox/msgbox.css">
   <link rel="stylesheet" href="options/onoffswitch.css">
   <link rel="stylesheet" href="vendor-overwrites/colorpicker/colorpicker.css">
@@ -164,11 +165,15 @@
 <div id="header">
   <h1 id="manage-heading" i18n-text="manageHeading"></h1>
 
-  <fieldset>
-
-    <legend id="filters">
-      <span i18n-text="manageFilters"></span><span id="filters-stats"></span>
-    </legend>
+  <details id="filters" data-pref="manage.filters.expanded">
+    <summary>
+      <h2 i18n-text="manageFilters">: <span id="filters-stats"></span></h2>
+      <svg id="reset-filters" class="svg-icon" viewBox="0 0 20 20">
+        <title i18n-text="genericResetLabel"></title>
+        <polygon points="16.2,5.5 14.5,3.8 10,8.3 5.5,3.8 3.8,5.5 8.3,10 3.8,14.5
+                         5.5,16.2 10,11.7 14.5,16.2 16.2,14.5 11.7,10 "/>
+      </svg>
+    </summary>
 
     <div class="filter-selection">
       <label>
@@ -232,12 +237,14 @@
       <span i18n-text="manageOnlyUpdates"></span>
     </label>
 
-    <input id="search" type="search" i18n-placeholder="searchStyles" spellcheck="false"
-           i18n-title="searchStylesTooltip"
-           data-filter=":not(.not-matching)"
-           data-filter-hide=".not-matching">
+    <div id="search-wrapper">
+      <input id="search" type="search" i18n-placeholder="searchStyles" spellcheck="false"
+             data-filter=":not(.not-matching)"
+             data-filter-hide=".not-matching">
+      <svg id="search-help" class="svg-icon info"><use xlink:href="#svg-icon-help"/></svg>
+    </div>
 
-  </fieldset>
+  </details>
 
   <p class="nowrap">
     <button id="check-all-updates" i18n-text="checkAllUpdates"><span id="update-progress"></span></button>
@@ -254,11 +261,11 @@
     <button id="check-all-updates-force" class="hidden" i18n-text="checkAllUpdatesForce"></button>
   </p>
 
-  <p>
+  <p id="add-style-wrapper">
     <a href="edit.html">
       <button id="add-style-label" i18n-text="addStyleLabel"></button>
     </a>
-    <label id="newStyleAsUsercss-wrapper" class="nobreak">
+    <label id="add-style-as-usercss-wrapper">
       <input type="checkbox" id="newStyleAsUsercss">
       <svg class="svg-icon checked"><use xlink:href="#svg-icon-checked"/></svg>
       <span i18n-text="manageNewStyleAsUsercss" i18n-title="optionsAdvancedNewStyleAsUsercss"></span>
@@ -287,10 +294,11 @@
         <label for="manage.newUI.favicons" i18n-text="manageFavicons">
           <input id="manage.newUI.favicons" type="checkbox">
           <svg class="svg-icon checked"><use xlink:href="#svg-icon-checked"/></svg>
+          <svg class="svg-icon select-arrow" data-toggle-on-click="#faviconsHelp">
+            <title i18n-text="optionsSubheading"></title>
+            <use xlink:href="#svg-icon-select-arrow"/>
+          </svg>
         </label>
-        <svg class="svg-icon info" viewBox="0 0 14 16" i18n-alt="helpAlt" data-toggle-on-click="#faviconsHelp">
-          <path fill-rule="evenodd" d="M6.3 5.69a.942.942 0 0 1-.28-.7c0-.28.09-.52.28-.7.19-.18.42-.28.7-.28.28 0 .52.09.7.28.18.19.28.42.28.7 0 .28-.09.52-.28.7a1 1 0 0 1-.7.3c-.28 0-.52-.11-.7-.3zM8 7.99c-.02-.25-.11-.48-.31-.69-.2-.19-.42-.3-.69-.31H6c-.27.02-.48.13-.69.31-.2.2-.3.44-.31.69h1v3c.02.27.11.5.31.69.2.2.42.31.69.31h1c.27 0 .48-.11.69-.31.2-.19.3-.42.31-.69H8V7.98v.01zM7 2.3c-3.14 0-5.7 2.54-5.7 5.68 0 3.14 2.56 5.7 5.7 5.7s5.7-2.55 5.7-5.7c0-3.15-2.56-5.69-5.7-5.69v.01zM7 .98c3.86 0 7 3.14 7 7s-3.14 7-7 7-7-3.12-7-7 3.14-7 7-7z"></path>
-        </svg>
         <div id="faviconsHelp" class="hidden" i18n-text="manageFaviconsHelp">
           <div>
             <label for="manage.newUI.faviconsGray" i18n-text="manageFaviconsGray">
@@ -316,14 +324,14 @@
 
   </details>
 
-  <div id="backup">
-    <h2 id="backup-title" i18n-text="backupButtons"></h2>
+  <details id="backup" data-pref="manage.backup.expanded">
+    <summary><h2 id="backup-title" i18n-text="backupButtons"></h2></summary>
     <span id="backup-message" i18n-text="backupMessage"></span>
     <p>
       <button id="file-all-styles" i18n-text="bckpInstStyles"></button>
       <button id="unfile-all-styles" i18n-text="retrieveBckp"></button>
     </p>
-  </div>
+  </details>
 
   <p id="manage-text" i18n-html="manageText"></p>
 
@@ -343,6 +351,11 @@
   <symbol id="svg-icon-select-arrow" viewBox="0 0 1792 1792">
     <path fill-rule="evenodd" d="M1408 704q0 26-19 45l-448 448q-19 19-45 19t-45-19l-448-448q-19-19-19-45t19-45 45-19h896q26 0 45 19t19 45z"/>
   </symbol>
+
+  <symbol id="svg-icon-help" viewBox="0 0 14 16">
+    <title i18n-text="helpAlt"></title>
+    <path fill-rule="evenodd" d="M6.3 5.69a.942.942 0 0 1-.28-.7c0-.28.09-.52.28-.7.19-.18.42-.28.7-.28.28 0 .52.09.7.28.18.19.28.42.28.7 0 .28-.09.52-.28.7a1 1 0 0 1-.7.3c-.28 0-.52-.11-.7-.3zM8 7.99c-.02-.25-.11-.48-.31-.69-.2-.19-.42-.3-.69-.31H6c-.27.02-.48.13-.69.31-.2.2-.3.44-.31.69h1v3c.02.27.11.5.31.69.2.2.42.31.69.31h1c.27 0 .48-.11.69-.31.2-.19.3-.42.31-.69H8V7.98v.01zM7 2.3c-3.14 0-5.7 2.54-5.7 5.68 0 3.14 2.56 5.7 5.7 5.7s5.7-2.55 5.7-5.7c0-3.15-2.56-5.69-5.7-5.69v.01zM7 .98c3.86 0 7 3.14 7 7s-3.14 7-7 7-7-3.12-7-7 3.14-7 7-7z"></path>
+  </symbol>
 </svg>
 
 </body>
diff --git a/manage/config-dialog.css b/manage/config-dialog.css
new file mode 100644
index 00000000..9edc3e1a
--- /dev/null
+++ b/manage/config-dialog.css
@@ -0,0 +1,112 @@
+/* config dialog */
+.config-dialog .config-heading {
+  float: right;
+  margin: -1.25rem 0 0 0;
+  font-size: 0.9em;
+}
+
+.config-dialog label {
+  display: flex;
+  padding: .75em 0;
+  align-items: center;
+}
+
+.config-dialog .select-resizer {
+  position: static;
+}
+
+.config-dialog label:first-child {
+  padding-top: 0;
+}
+
+.config-dialog label:last-child {
+  padding-bottom: 0;
+}
+
+.config-dialog label:not(:first-child) {
+  border-top: 1px dotted #ccc;
+}
+
+.config-dialog label > :first-child {
+  margin-right: 8px;
+  flex-grow: 1;
+}
+
+.config-dialog label:not([disabled]) > :first-child {
+  cursor: default;
+}
+
+.config-dialog label:not([disabled]):hover > :first-child {
+  text-shadow: 0 0 0.01px rgba(0, 0, 0, .25);
+  cursor: pointer;
+}
+
+.config-dialog .dirty:after {
+  content: "*";
+  position: absolute;
+  left: 6px;
+}
+
+.config-dialog .dirty {
+  font-style: italic;
+}
+
+.config-dialog input,
+.config-dialog select,
+.config-dialog .onoffswitch {
+  width: var(--onoffswitch-width);
+  margin: 0;
+  height: 2em;
+  box-sizing: border-box;
+  vertical-align: middle;
+}
+
+.config-dialog .select-resizer,
+.config-dialog select {
+  width: auto;
+  min-width: var(--onoffswitch-width);
+  max-width: 124px;
+  left: auto;
+  position: relative;
+}
+
+.config-dialog .onoffswitch {
+  height: auto;
+  margin: calc((2em - 12px) / 2) 0;
+}
+
+.config-dialog input[type="text"] {
+  padding-left: 0.25em;
+}
+
+.config-dialog label > :last-child {
+  box-sizing: border-box;
+  flex-shrink: 0;
+}
+
+.config-dialog label > :last-child:not(.onoffswitch):not(.select-resizer) > :not(:last-child) {
+  margin-right: 4px;
+}
+
+.cm-colorview::before,
+.color-swatch {
+  width: var(--onoffswitch-width) !important;
+  height: 20px !important;
+}
+
+.cm-colorview::before {
+  margin: 1px !important;
+}
+
+.color-swatch {
+  position: absolute;
+  border: 1px solid gray;
+  margin-top: -22px;
+  cursor: pointer;
+}
+
+.colorpicker-popup {
+  z-index: 2147483647 !important;
+  border: none !important;
+  box-shadow: 3px 3px 50px rgba(0,0,0,.5) !important;
+}
diff --git a/manage/config-dialog.js b/manage/config-dialog.js
index 6b24fdaa..6c6e3273 100644
--- a/manage/config-dialog.js
+++ b/manage/config-dialog.js
@@ -6,35 +6,79 @@ function configDialog(style) {
   const varsHash = deepCopy(data.vars) || {};
   const varNames = Object.keys(varsHash);
   const vars = varNames.map(name => varsHash[name]);
+  let varsInitial = getInitialValues(varsHash);
+
   const elements = [];
   const colorpicker = window.colorpicker();
+  const isPopup = location.href.includes('popup.html');
+  const buttons = {};
 
   buildConfigForm();
   renderValues();
 
   return messageBox({
     title: `${style.name} v${data.version}`,
-    className: 'config-dialog',
+    className: 'config-dialog' + (isPopup ? ' stylus-popup' : ''),
     contents: [
       $create('.config-heading', data.supportURL &&
         $createLink({className: '.external-support', href: data.supportURL}, t('externalFeedback'))),
       $create('.config-body', elements)
     ],
     buttons: [
-      t('confirmSave'),
-      {
-        textContent: t('confirmDefault'),
-        onclick: useDefault
-      },
-      t('confirmCancel')
-    ]
-  }).then(({button, esc}) => {
-    if (button !== 1) {
-      colorpicker.hide();
+      {textContent: t('confirmSave'), dataset: {cmd: 'save'}, disabled: true, onclick: save},
+      {textContent: t('confirmDefault'), dataset: {cmd: 'default'}, onclick: useDefault},
+      {textContent: t('confirmClose'), dataset: {cmd: 'close'}},
+    ],
+    onshow,
+  }).then(() => {
+    document.body.style.minWidth = '';
+    document.body.style.minHeight = '';
+    colorpicker.hide();
+  });
+
+  function getInitialValues(source) {
+    const data = {};
+    for (const name of varNames) {
+      const va = source[name];
+      data[name] = isDefault(va) ? va.default : va.value;
     }
-    if (button > 0 || esc || !vars.length || !vars.some(va => va.dirty)) {
+    return data;
+  }
+
+  function onshow(box) {
+    if (isPopup) {
+      adjustSizeForPopup(box);
+      box.style.animationDuration = '0s';
+    }
+    box.addEventListener('change', onchange);
+    buttons.save = $('[data-cmd="save"]', box);
+    buttons.default = $('[data-cmd="default"]', box);
+    buttons.close = $('[data-cmd="close"]', box);
+    updateButtons();
+  }
+
+  function onchange({target}) {
+    // invoked after element's own onchange so 'va' contains the updated value
+    const va = target.va;
+    if (va) {
+      va.dirty = varsInitial[va.name] !== (isDefault(va) ? va.default : va.value);
+      target.closest('label').classList.toggle('dirty', va.dirty);
+      updateButtons();
+    }
+  }
+
+  function updateButtons() {
+    const someDirty = vars.some(va => va.dirty);
+    buttons.save.disabled = !someDirty;
+    buttons.default.disabled = vars.every(isDefault);
+    buttons.close.textContent = t(someDirty ? 'confirmCancel' : 'confirmClose');
+  }
+
+  function save() {
+    if (!vars.length || !vars.some(va => va.dirty)) {
       return;
     }
+    style.enabled = true;
     style.reason = 'config';
     const styleVars = style.usercssData.vars;
     const bgStyle = BG.cachedStyles.byId.get(style.id);
@@ -52,7 +96,7 @@ function configDialog(style) {
         error = ['type ', '*' + va.type, ' != ', '*' + bgva.type];
       } else
       if ((va.type === 'select' || va.type === 'dropdown') &&
-          va.value !== null && va.value !== undefined &&
+          !isDefault(va) &&
           bgva.options.every(o => o.name !== va.value)) {
         error = `'${va.value}' not in the updated '${va.type}' list`;
       } else if (!va.dirty) {
@@ -76,33 +120,52 @@ function configDialog(style) {
             $create({tag: 'li', appendChild: msg}))),
       ]);
     }
-    return numValid && BG.usercssHelper.save(style);
-  });
+    return numValid && BG.usercssHelper.save(style).then(saved => {
+      varsInitial = getInitialValues(deepCopy(saved.usercssData.vars));
+      vars.forEach(va => onchange({target: va.input}));
+      updateButtons();
+    });
+  }
+
+  function useDefault() {
+    for (const va of vars) {
+      va.value = null;
+      onchange({target: va.input});
+    }
+    renderValues();
+  }
+
+  function isDefault(va) {
+    return va.value === null || va.value === undefined || va.value === va.default;
+  }
 
   function buildConfigForm() {
     for (const va of vars) {
       let children;
       switch (va.type) {
         case 'color':
-          va.inputColor = $create('.color-swatch', {va, onclick: showColorpicker});
           children = [
             $create('.cm-colorview', [
-              va.inputColor,
+              va.input = $create('.color-swatch', {
+                va,
+                onclick: showColorpicker
+              }),
             ]),
           ];
           break;
 
         case 'checkbox':
-          va.input = $create('input.slider', {type: 'checkbox'});
-          va.input.onchange = () => {
-            va.dirty = true;
-            va.value = String(Number(va.input.checked));
-          };
           children = [
             $create('span.onoffswitch', [
-              va.input,
+              va.input = $create('input.slider', {
+                va,
+                type: 'checkbox',
+                onchange() {
+                  va.value = va.input.checked ? '1' : '0';
+                },
+              }),
               $create('span'),
-            ])
+            ]),
           ];
           break;
 
@@ -110,26 +173,33 @@ function configDialog(style) {
         case 'dropdown':
         case 'image':
           // TODO: a image picker input?
-          va.input = $create('.select-resizer', [
-            $create('select', va.options.map(o =>
-              $create('option', {value: o.name}, o.label))),
-            $create('SVG:svg.svg-icon.select-arrow',
-              $create('SVG:use', {'xlink:href': '#svg-icon-select-arrow'})),
-          ]);
-          va.input.onchange = () => {
-            va.dirty = true;
-            va.value = va.input.value;
-          };
-          children = [va.input];
+          children = [
+            $create('.select-resizer', [
+              va.input = $create('select', {
+                va,
+                onchange() {
+                  va.value = this.value;
+                }
+              },
+              va.options.map(o =>
+                $create('option', {value: o.name}, o.label))),
+              $create('SVG:svg.svg-icon.select-arrow',
+                $create('SVG:use', {'xlink:href': '#svg-icon-select-arrow'})),
+            ]),
+          ];
           break;
 
         default:
-          va.input = $create('input', {type: 'text'});
-          va.input.oninput = () => {
-            va.dirty = true;
-            va.value = va.input.value;
-          };
-          children = [va.input];
+          children = [
+            va.input = $create('input', {
+              va,
+              type: 'text',
+              oninput() {
+                va.value = this.value;
+                this.dispatchEvent(new Event('change', {bubbles: true}));
+              },
+            }),
+          ];
           break;
       }
       elements.push(
@@ -142,10 +212,9 @@ function configDialog(style) {
 
   function renderValues() {
     for (const va of vars) {
-      const useDefault = va.value === null || va.value === undefined;
-      const value = useDefault ? va.default : va.value;
+      const value = isDefault(va) ? va.default : va.value;
       if (va.type === 'color') {
-        va.inputColor.style.backgroundColor = value;
+        va.input.style.backgroundColor = value;
         if (colorpicker.options.va === va) {
           colorpicker.setColor(value);
         }
@@ -157,15 +226,6 @@ function configDialog(style) {
     }
   }
 
-  function useDefault() {
-    for (const va of vars) {
-      const hasValue = va.value !== null && va.value !== undefined;
-      va.dirty = hasValue && va.value !== va.default;
-      va.value = null;
-    }
-    renderValues();
-  }
-
   function showColorpicker() {
     window.removeEventListener('keydown', messageBox.listeners.key, true);
     const box = $('#message-box-contents');
@@ -182,9 +242,9 @@ function configDialog(style) {
 
   function onColorChanged(newColor) {
     if (newColor) {
-      this.va.dirty = true;
       this.va.value = newColor;
-      this.va.inputColor.style.backgroundColor = newColor;
+      this.va.input.style.backgroundColor = newColor;
+      this.va.input.dispatchEvent(new Event('change', {bubbles: true}));
     }
     debounce(restoreEscInDialog);
   }
@@ -194,4 +254,22 @@ function configDialog(style) {
       window.addEventListener('keydown', messageBox.listeners.key, true);
     }
   }
+
+  function adjustSizeForPopup(box) {
+    box.style = 'white-space: nowrap !important';
+    box.firstElementChild.style = 'max-width: none; max-height: none;'.replace(/;/g, '!important;');
+    const {offsetWidth, offsetHeight} = box.firstElementChild;
+    box.style = box.firstElementChild.style = '';
+
+    const colorpicker = document.body.appendChild(
+      $create('.colorpicker-popup', {style: 'display: none!important'}));
+    const MIN_WIDTH = parseFloat(getComputedStyle(colorpicker).width) || 350;
+    const MIN_HEIGHT = 250;
+    colorpicker.remove();
+
+    const width = Math.max(Math.min(offsetWidth / 0.9 + 2, 800), MIN_WIDTH);
+    const height = Math.max(Math.min(offsetHeight / 0.9 + 2, 600), MIN_HEIGHT);
+    document.body.style.setProperty('min-width', width + 'px', 'important');
+    document.body.style.setProperty('min-height', height + 'px', 'important');
+  }
 }
diff --git a/manage/filters.js b/manage/filters.js
index aae54d43..87ad4f0a 100644
--- a/manage/filters.js
+++ b/manage/filters.js
@@ -1,4 +1,4 @@
-/* global installed */
+/* global installed messageBox */
 'use strict';
 
 const filtersSelector = {
@@ -31,6 +31,25 @@ onDOMready().then(onBackgroundReady).then(() => {
   if (urlFilterParam) {
     $('#search').value = 'url:' + urlFilterParam;
   }
+  $('#search-help').onclick = () => {
+    messageBox({
+      className: 'help-text',
+      title: t('searchStyles'),
+      contents:
+        $create('ul',
+          t('searchStylesHelp').split('\n').map(line =>
+            $create('li', line.split(/(<.*?>)/).map((s, i, words) => {
+              if (s.startsWith('<')) {
+                const num = words.length;
+                const className = i === num - 2 && !words[num - 1] ? '.last' : '';
+                return $create('mark' + className, s.slice(1, -1));
+              } else {
+                return s;
+              }
+            })))),
+      buttons: [t('confirmOK')],
+    });
+  };
 
   $$('select[id$=".invert"]').forEach(el => {
     const slave = $('#' + el.id.replace('.invert', ''));
@@ -76,6 +95,36 @@ onDOMready().then(onBackgroundReady).then(() => {
     }
   });
 
+  $('#reset-filters').onclick = event => {
+    event.preventDefault();
+    if (!filtersSelector.hide) {
+      return;
+    }
+    for (const el of $$('#filters [data-filter]')) {
+      let value;
+      if (el.type === 'checkbox' && el.checked) {
+        value = el.checked = false;
+      } else if (el.value) {
+        value = el.value = '';
+      }
+      if (value !== undefined) {
+        el.lastValue = value;
+        if (el.id in prefs.readOnlyValues) {
+          prefs.set(el.id, false);
+        }
+      }
+    }
+    filterOnChange({forceRefilter: true});
+  };
+
+  // Adjust width after selects are visible
+  prefs.subscribe(['manage.filters.expanded'], () => {
+    const el = $('#filters');
+    if (el.open) {
+      $$('select', el).forEach(select => select.adjustWidth());
+    }
+  });
+
   filterOnChange({forceRefilter: true});
 });
 
@@ -303,7 +352,7 @@ function showFiltersStats() {
     debounce(showFiltersStats, 100);
     return;
   }
-  $('#filters').classList.toggle('active', filtersSelector.hide !== '');
+  $('#filters summary').classList.toggle('active', filtersSelector.hide !== '');
   const numTotal = BG.cachedStyles.list.length;
   const numHidden = installed.getElementsByClassName('entry hidden').length;
   const numShown = Math.min(numTotal - numHidden, installed.children.length);
@@ -320,10 +369,11 @@ function showFiltersStats() {
 
 function searchStyles({immediately, container}) {
   const searchElement = $('#search');
-  const urlMode = /^\s*url:/i.test(searchElement.value);
+  const value = searchElement.value;
+  const urlMode = /^\s*url:/i.test(value);
   const query = urlMode
-    ? searchElement.value.replace(/^\s*url:/i, '').trim()
-    : searchElement.value.toLocaleLowerCase();
+    ? value.replace(/^\s*url:/i, '').trim()
+    : value.toLocaleLowerCase();
   const queryPrev = searchElement.lastValue || '';
   if (query === queryPrev && !immediately && !container) {
     return;
@@ -334,6 +384,12 @@ function searchStyles({immediately, container}) {
   }
   searchElement.lastValue = query;
 
+  const trimmed = query.trim();
+  const rx = trimmed.startsWith('/') && trimmed.indexOf('/', 1) > 0 &&
+    tryRegExp(...(value.match(/^\s*\/(.*?)\/([gimsuy]*)\s*$/) || []).slice(1));
+  const words = rx ? null :
+    trimmed.startsWith('"') && trimmed.endsWith('"') ? [value.trim().slice(1, -1)] :
+      query.split(/\s+/).filter(s => s.length > 2);
   const searchInVisible = !urlMode && queryPrev && query.includes(queryPrev);
   const entries = container && container.children || container ||
     (searchInVisible ? $$('.entry:not(.hidden)') : installed.children);
@@ -349,6 +405,7 @@ function searchStyles({immediately, container}) {
         urlMode ||
         isMatchingText(style.name) ||
         style.url && isMatchingText(style.url) ||
+        style.sourceCode && isMatchingText(style.sourceCode) ||
         isMatchingStyle(style)));
     }
     if (entry.classList.contains('not-matching') !== !isMatching) {
@@ -384,6 +441,17 @@ function searchStyles({immediately, container}) {
   }
 
   function isMatchingText(text) {
-    return text.toLocaleLowerCase().indexOf(query) >= 0;
+    if (rx) {
+      return rx.test(text);
+    }
+    for (let pass = 1; pass <= 2; pass++) {
+      for (const word of words) {
+        if (text.includes(word)) {
+          return true;
+        }
+      }
+      text = text.toLocaleLowerCase();
+    }
+    return false;
   }
 }
diff --git a/manage/import-export.js b/manage/import-export.js
index a4c91a70..865915c9 100644
--- a/manage/import-export.js
+++ b/manage/import-export.js
@@ -34,7 +34,17 @@ function importFromFile({fileTypeFilter, file} = {}) {
         const fReader = new FileReader();
         fReader.onloadend = event => {
           fileInput.remove();
-          importFromString(event.target.result).then(numStyles => {
+          const text = event.target.result;
+          const maybeUsercss = !/^[\s\r\n]*\[/.test(text) &&
+            (text.includes('==UserStyle==') || /==UserStyle==/i.test(text));
+          (!maybeUsercss ?
+            importFromString(text) :
+            getOwnTab().then(tab => {
+              tab.url = URL.createObjectURL(new Blob([text], {type: 'text/css'}));
+              return BG.usercssHelper.openInstallPage(tab, {direct: true})
+                .then(() => URL.revokeObjectURL(tab.url));
+            })
+          ).then(numStyles => {
             document.body.style.cursor = '';
             resolve(numStyles);
           });
diff --git a/manage/manage.css b/manage/manage.css
index c21a3e5f..a93295f3 100644
--- a/manage/manage.css
+++ b/manage/manage.css
@@ -79,6 +79,7 @@ select {
 
 #header h1 {
   margin-top: 0;
+  margin-bottom: .3em;
 }
 
 #header a[href^="edit"] {
@@ -90,25 +91,16 @@ select {
   margin-bottom: .25em;
 }
 
-#newStyleAsUsercss-wrapper:not(:hover) input:not(:checked) ~ a svg {
+#add-style-as-usercss-wrapper {
+  display: inline-flex;
+}
+
+#add-style-as-usercss-wrapper:not(:hover) input:not(:checked) ~ a svg {
   fill: #aaa;
 }
 
 #usercss-wiki svg {
-  margin-top: -2px;
-}
-
-.nobreak {
-  white-space: nowrap;
-}
-
-label.nobreak input {
-  vertical-align: sub;
-  margin: 0;
-}
-
-.firefox .chromium-only {
-  display: none;
+  margin-top: -4px;
 }
 
 #installed {
@@ -264,9 +256,24 @@ label.nobreak input {
 }
 
 /* collapsibles */
+#header details:not(#filters),
+#add-style-wrapper {
+  padding-bottom: .7em;
+}
 
+#add-style-wrapper,
+#options :last-child,
+#backup :last-child {
+  margin-bottom: 0;
+}
+
+#header details:not([open]),
 #header details:not([open]) h2 {
-  margin-bottom: -.25em;
+  padding-bottom: 0;
+}
+
+#header details[open] summary {
+  padding-bottom: .5em;
 }
 
 #header summary {
@@ -274,7 +281,6 @@ label.nobreak input {
   margin-left: -13px;
   cursor: pointer;
   outline: none;
-  margin-bottom: 8px;
 }
 
 #header summary h2 {
@@ -326,6 +332,7 @@ label.nobreak input {
 
 .filter-selection {
   position: relative;
+  left: -9px;
 }
 
 #header label {
@@ -346,10 +353,6 @@ label.nobreak input {
   margin-top: -2px;
 }
 
-.firefox #header .filter-selection label .checkmate {
-  margin: 0;
-}
-
 .newUI #newUIoptions > label {
   padding-left: 0;
 }
@@ -361,10 +364,7 @@ label.nobreak input {
   max-width: 100%;
   padding-left: 4px;
   padding-right: 14px;
-}
-
-.firefox .filter-selection select {
-  padding-left: 0;
+  margin-left: 4px;
 }
 
 .filter-selection .select-arrow {
@@ -382,17 +382,13 @@ label.nobreak input {
   left: 16px;
 }
 
-.firefox .select-resizer {
-  left: 16px;
-}
-
-fieldset > label,
-fieldset > .filter-selection {
+#filters label,
+#filters .filter-selection {
   transition: background-color .25s;
 }
 
-fieldset > label:hover,
-fieldset > .filter-selection:hover {
+#filters label:hover,
+#filters .filter-selection:hover {
   background-color: hsla(0, 0%, 50%, .2);
 }
 
@@ -646,6 +642,7 @@ fieldset > .filter-selection:hover {
   align-items: center;
   margin-bottom: auto;
   flex-wrap: wrap;
+  position: relative;
 }
 
 #newUIoptions input[type="number"] {
@@ -653,6 +650,18 @@ fieldset > .filter-selection:hover {
   margin-right: .5em;
 }
 
+#newUIoptions [data-toggle-on-click] {
+  transform: rotate(-90deg);
+  cursor: pointer;
+  right: -16px;
+  top: 0;
+  pointer-events: auto;
+}
+
+#newUIoptions [data-toggle-on-click][open] {
+  transform: none;
+}
+
 input[id^="manage.newUI"] {
   margin-left: 0;
 }
@@ -751,26 +760,14 @@ input[id^="manage.newUI"] {
   display: none !important;
 }
 
-fieldset {
-  border-width: 1px;
-  border-radius: 6px;
-  margin: 1em 0;
-  min-width: 0;
-  max-width: 250px;
-}
-
-fieldset > input,
-fieldset > label {
+#filters label {
   display: flex;
   align-items: center;
-}
-
-#header fieldset > label {
   padding-left: 20px;
 }
 
-#header fieldset > label input[type="checkbox"]:not(.slider),
-#header fieldset > label input[type="checkbox"]:not(.slider):checked + .svg-icon.checked{
+#filters label input[type="checkbox"]:not(.slider),
+#filters label input[type="checkbox"]:not(.slider):checked + .svg-icon.checked{
   left: 4px;
 }
 
@@ -778,28 +775,82 @@ fieldset > label {
   border: 1px solid transparent;
 }
 
-#filters.active {
+#filters summary h2 {
+  margin-left: -4px;
+}
+
+.active #filters-stats {
   background-color: darkcyan;
   border-color: darkcyan;
   color: white;
+  font-size: 0.7rem;
+  font-weight: normal;
+  padding: 2px 5px;
+  position: relative;
+  top: -2px;
 }
 
-#filters:not(.active) #filters-stats {
+#reset-filters {
+  position: absolute;
+  margin-top: 2px;
+  fill: hsla(180, 50%, 27%, .5);
+  width: 24px; /* widen the click area a bit */
+  height: 20px;
+  padding: 2px;
+  box-sizing: border-box;
+}
+
+#reset-filters:hover {
+  fill: hsla(180, 50%, 27%, 1);
+}
+
+#filters summary:not(.active) #reset-filters,
+#filters summary:not(.active) #filters-stats {
   display: none;
 }
 
-#filters-stats::before {
-  content: ": ";
+#search-wrapper {
+  display: flex;
+  align-items: center;
+  flex-wrap: wrap;
 }
 
 #search {
-  width: calc(100% - 4px);
-  margin: 0.25rem 4px 0;
-  border-radius: 0.25rem;
+  flex-grow: 1;
+  margin: 0.25rem 0 0;
   padding-left: 0.25rem;
   border-width: 1px;
 }
 
+#search-wrapper .info {
+  margin: 4px -5px 0 8px;
+}
+
+#message-box.help-text > div {
+  max-width: 26rem;
+}
+.help-text li:not(:last-child) {
+  margin-bottom: 1em;
+}
+
+.help-text mark {
+  background-color: rgba(128, 128, 128, .15);
+  color: currentColor;
+  padding: 2px 6px;
+  font-weight: bold;
+  font-family: monospace;
+  border: 1px solid rgba(128, 128, 128, .25);
+  display: inline-block;
+  margin: 2px;
+}
+
+.help-text mark.last {
+  display: block;
+  width: -moz-min-content;
+  width: min-content;
+  white-space: nowrap;
+}
+
 #import ul {
   margin-left: 0;
   padding-left: 0;
@@ -860,109 +911,6 @@ fieldset > label {
   text-overflow: ellipsis;
 }
 
-/* config dialog */
-.config-dialog .config-heading {
-  float: right;
-  margin: -1.25rem 0 0 0;
-  font-size: 0.9em;
-}
-
-.config-dialog label {
-  display: flex;
-  padding: .75em 0;
-  align-items: center;
-}
-
-.config-dialog .select-resizer {
-  position: static;
-}
-
-.config-dialog label:first-child {
-  padding-top: 0;
-}
-
-.config-dialog label:last-child {
-  padding-bottom: 0;
-}
-
-.config-dialog label:not(:first-child) {
-  border-top: 1px dotted #ccc;
-}
-
-.config-dialog label > :first-child {
-  margin-right: 8px;
-  flex-grow: 1;
-}
-
-.config-dialog label:not([disabled]) > :first-child {
-  cursor: default;
-}
-
-.config-dialog label:not([disabled]):hover > :first-child {
-  text-shadow: 0 0 0.01px rgba(0, 0, 0, .25);
-  cursor: pointer;
-}
-
-.config-dialog input,
-.config-dialog select,
-.config-dialog .onoffswitch {
-  width: var(--onoffswitch-width);
-  margin: 0;
-  height: 2em;
-  box-sizing: border-box;
-  vertical-align: middle;
-}
-
-.config-dialog .select-resizer,
-.config-dialog select {
-  width: auto;
-  min-width: var(--onoffswitch-width);
-  max-width: 124px;
-  left: auto;
-  position: relative;
-}
-
-.config-dialog .onoffswitch {
-  height: auto;
-  margin: calc((2em - 12px) / 2) 0;
-}
-
-.config-dialog input[type="text"] {
-  padding-left: 0.25em;
-}
-
-.config-dialog label > :last-child {
-  box-sizing: border-box;
-  flex-shrink: 0;
-}
-
-.config-dialog label > :last-child:not(.onoffswitch):not(.select-resizer) > :not(:last-child) {
-  margin-right: 4px;
-}
-
-.cm-colorview::before,
-.color-swatch {
-  width: var(--onoffswitch-width) !important;
-  height: 20px !important;
-}
-
-.cm-colorview::before {
-  margin: 1px !important;
-}
-
-.color-swatch {
-  position: absolute;
-  border: 1px solid gray;
-  margin-top: -22px;
-  cursor: pointer;
-}
-
-.colorpicker-popup {
-  z-index: 2147483647 !important;
-  border: none !important;
-  box-shadow: 3px 3px 50px rgba(0,0,0,.5) !important;
-}
-
 @keyframes fadein {
   from {
     opacity: 0;
@@ -998,7 +946,6 @@ fieldset > label {
   }
 
   #header p,
-  #header fieldset div,
   #backup {
     display: inline-block;
   }
@@ -1011,8 +958,7 @@ fieldset > label {
     margin-right: 1em;
   }
 
-  #backup p,
-  #header fieldset {
+  #backup p {
     margin: 0;
   }
 
@@ -1053,12 +999,6 @@ fieldset > label {
     padding-left: 0;
   }
 
-  fieldset {
-    max-width: none;
-    margin-top: 0;
-    margin-right: 2em;
-  }
-
   #header h1,
   #header h2,
   #header h3,
@@ -1088,21 +1028,10 @@ fieldset > label {
 
   .newUI #header > *:not(h1),
   .newUI #newUIoptions,
-  #newUIoptions > *,
-  fieldset label {
+  #newUIoptions > * {
     display: inline;
   }
 
-  fieldset {
-    border: none;
-    margin: 0;
-    padding: 0 0 1em;
-  }
-
-  fieldset legend {
-    display: none;
-  }
-
   #header label {
     white-space: nowrap;
   }
@@ -1111,3 +1040,29 @@ fieldset > label {
     word-break: break-all;
   }
 }
+
+@supports (-moz-appearance: none) {
+  .chromium-only {
+    display: none;
+  }
+
+  #header .filter-selection label .checkmate {
+    margin: 0;
+  }
+
+  .filter-selection select {
+    padding-left: 0;
+  }
+
+  .select-resizer {
+    left: 16px;
+  }
+
+  #reset-filters {
+    margin-top: 4px;
+  }
+
+  #filters summary h2 {
+    margin-left: -2px;
+  }
+}
diff --git a/manage/manage.js b/manage/manage.js
index 58435e1c..4069337a 100644
--- a/manage/manage.js
+++ b/manage/manage.js
@@ -66,7 +66,15 @@ function initGlobalEvents() {
   $$('[data-toggle-on-click]').forEach(el => {
     // dataset on SVG doesn't work in Chrome 49-??, works in 57+
     const target = $(el.getAttribute('data-toggle-on-click'));
-    el.onclick = () => target.classList.toggle('hidden');
+    el.onclick = event => {
+      event.preventDefault();
+      target.classList.toggle('hidden');
+      if (target.classList.contains('hidden')) {
+        el.removeAttribute('open');
+      } else {
+        el.setAttribute('open', '');
+      }
+    };
   });
 
   // triggered automatically by setupLivePrefs() below
diff --git a/msgbox/msgbox.css b/msgbox/msgbox.css
index da232671..cd6cf48d 100644
--- a/msgbox/msgbox.css
+++ b/msgbox/msgbox.css
@@ -132,6 +132,18 @@
   margin: 0 .375rem;
 }
 
+/* popup */
+#message-box.stylus-popup {
+  margin: 0;
+  align-items: center;
+  justify-content: center;
+}
+#message-box.stylus-popup > div {
+  max-width: 90vw;
+  top: auto;
+  right: auto;
+}
+
 @keyframes fadein {
   from {
     opacity: 0;
diff --git a/msgbox/msgbox.js b/msgbox/msgbox.js
index cbe3b44f..c02b1eef 100644
--- a/msgbox/msgbox.js
+++ b/msgbox/msgbox.js
@@ -70,11 +70,11 @@ function messageBox({
           $create(`#${id}-contents`, tHTML(contents)),
           $create(`#${id}-buttons`,
             buttons.map((content, buttonIndex) => content &&
-              $create('button', {
+              $create('button', Object.assign({
                 buttonIndex,
-                textContent: content.textContent || content,
-                onclick: content.onclick || messageBox.listeners.button,
-              }))),
+                textContent: typeof content === 'object' ? '' : content,
+                onclick: messageBox.listeners.button,
+              }, typeof content === 'object' && content)))),
         ]),
       ]);
   }
diff --git a/popup.html b/popup.html
index 129209ee..c9b51b5a 100644
--- a/popup.html
+++ b/popup.html
@@ -4,8 +4,6 @@
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <link rel="stylesheet" href="global.css">
-  <link rel="stylesheet" href="popup/popup.css">
-  <link rel="stylesheet" href="popup/search-results.css">
 
   <style id="firefox-transitions-bug-suppressor">
     /* restrict to FF */
@@ -34,6 +32,11 @@
       <div class="actions">
         <a href="#" class="enable" i18n-text="enableStyleLabel"></a>
         <a href="#" class="disable" i18n-text="disableStyleLabel"></a>
+        <a href="#" class="configure" i18n-title="configureStyle">
+          <svg class="svg-icon config" viewBox="0 0 14 16">
+            <path d="m6.2578 1.1191c-0.4526 0-0.81641 0.36381-0.81641 0.81641v0.69531a5.5932 5.5932 0 0 0-1.1328 0.47266l-0.49414-0.49414c-0.16002-0.16002-0.36907-0.24023-0.57812-0.24023-0.20905 0-0.41811 0.080216-0.57812 0.24023l-1.0488 1.0488c-0.32004 0.32004-0.32004 0.83621 0 1.1562l0.49023 0.49023a5.5932 5.5932 0 0 0-0.4668 1.1348h-0.69726c-0.4526 0-0.81641 0.36576-0.81641 0.81836v1.4844c0 0.4526 0.36381 0.81641 0.81641 0.81641h0.69726a5.5932 5.5932 0 0 0 0.4707 1.1328l-0.49414 0.49414c-0.32004 0.32004-0.32004 0.83426 0 1.1543l1.0488 1.0508c0.32004 0.32003 0.83621 0.32003 1.1562 0l0.49023-0.49024a5.5932 5.5932 0 0 0 1.1367 0.4668v0.69727c0 0.4526 0.36381 0.81641 0.81641 0.81641h1.4844c0.4526 0 0.81641-0.36381 0.81641-0.81641v-0.69727a5.5932 5.5932 0 0 0 1.1328-0.4707l0.49414 0.49414c0.32004 0.32003 0.83622 0.32003 1.1562 0l1.0488-1.0508c0.32004-0.32004 0.32004-0.83426 0-1.1543l-0.49023-0.49023a5.5932 5.5932 0 0 0 0.4668-1.1367h0.69726c0.4526 0 0.81641-0.36381 0.81641-0.81641v-1.4844c0-0.4526-0.36381-0.81836-0.81641-0.81836h-0.69726a5.5932 5.5932 0 0 0-0.4707-1.1309l0.49414-0.49414c0.32004-0.32004 0.32004-0.83621 0-1.1562l-1.0488-1.0488c-0.16002-0.16002-0.36907-0.24023-0.57812-0.24023s-0.41811 0.080216-0.57812 0.24023l-0.49023 0.49023a5.5932 5.5932 0 0 0-1.1367-0.4668v-0.69727c0-0.4526-0.36381-0.81641-0.81641-0.81641zm0.56836 0.7793h0.34766c0.22291 0 0.40234 0.17943 0.40234 0.40234v1.1621a4.5763 4.5763 0 0 1 2.2227 0.92383l0.82422-0.82422c0.15762-0.15762 0.41074-0.15762 0.56836 0l0.24609 0.24609c0.15762 0.15762 0.15762 0.41074 0 0.56836l-0.82226 0.82227a4.5763 4.5763 0 0 1 0.91797 2.2246h1.166c0.22291 0 0.40234 0.17943 0.40234 0.40234v0.34766c0 0.22291-0.17943 0.40234-0.40234 0.40234h-1.1641a4.5763 4.5763 0 0 1-0.92188 2.2227l0.82422 0.82422c0.15762 0.15762 0.15762 0.41074 0 0.56836l-0.24609 0.24609c-0.15762 0.15763-0.41074 0.15763-0.56836 0l-0.82227-0.82226a4.5763 4.5763 0 0 1-2.2246 0.91797v1.166c0 0.22291-0.17943 0.40234-0.40234 0.40234h-0.34766c-0.22291 0-0.40234-0.17943-0.40234-0.40234v-1.1641a4.5763 4.5763 0 0 1-2.2227-0.92188l-0.82422 0.82422c-0.15762 0.15763-0.41074 0.15763-0.56836 0l-0.24609-0.24609c-0.15762-0.15762-0.15762-0.41074 0-0.56836l0.82226-0.82226a4.5763 4.5763 0 0 1-0.91797-2.2246h-1.166c-0.22291 0-0.40234-0.17943-0.40234-0.40234v-0.34766c0-0.22291 0.17943-0.40234 0.40234-0.40234h1.1641a4.5763 4.5763 0 0 1 0.92188-2.2227l-0.82422-0.82422c-0.15762-0.15762-0.15762-0.41074 0-0.56836l0.24609-0.24609c0.15762-0.15762 0.41074-0.15762 0.56836 0l0.82227 0.82227a4.5763 4.5763 0 0 1 2.2246-0.91797v-1.166c0-0.22291 0.17943-0.40234 0.40234-0.40234zm0.17383 2.7109a3.3898 3.3898 0 0 0-3.3906 3.3906 3.3898 3.3898 0 0 0 3.3906 3.3887 3.3898 3.3898 0 0 0 3.3906-3.3887 3.3898 3.3898 0 0 0-3.3906-3.3906zm0 1.1875a2.2034 2.2034 0 0 1 2.2031 2.2031 2.2034 2.2034 0 0 1-2.2031 2.2031 2.2034 2.2034 0 0 1-2.2031-2.2031 2.2034 2.2034 0 0 1 2.2031-2.2031z"/>
+          </svg>
+        </a>
         <a class="style-edit-link" href="edit.html?id=" i18n-title="editStyleLabel">
           <svg class="svg-icon edit" viewBox="0 0 14 16">
             <path fill-rule="evenodd" d="M0 12v3h3l8-8-3-3-8 8zm3 2H1v-2h1v1h1v1zm10.3-9.3L12 6 9 3l1.3-1.3a.996.996 0 0 1 1.41 0l1.59 1.59c.39.39.39 1.02 0 1.41z"/>
@@ -117,11 +120,24 @@
     </div>
   </template>
 
+  <link rel="stylesheet" href="vendor-overwrites/colorpicker/colorpicker.css">
+  <script src="vendor-overwrites/colorpicker/colorpicker.js"></script>
+
+  <link rel="stylesheet" href="msgbox/msgbox.css">
+  <script src="msgbox/msgbox.js"></script>
+
+  <link rel="stylesheet" href="options/onoffswitch.css">
+  <link rel="stylesheet" href="manage/config-dialog.css">
+  <script src="manage/config-dialog.js"></script>
+
   <script src="js/dom.js"></script>
   <script src="js/messaging.js"></script>
   <script src="js/localization.js"></script>
   <script src="js/prefs.js"></script>
   <script src="content/apply.js"></script>
+
+  <link rel="stylesheet" href="popup/popup.css">
+  <link rel="stylesheet" href="popup/search-results.css">
   <script src="popup/popup.js"></script>
   <script src="popup/search-results.js"></script>
   <script src="popup/hotkeys.js"></script>
diff --git a/popup/hotkeys.js b/popup/hotkeys.js
index 053d7e1c..dedf491b 100644
--- a/popup/hotkeys.js
+++ b/popup/hotkeys.js
@@ -1,18 +1,36 @@
 /* global applyOnMessage installed */
 'use strict';
 
-window.addEventListener('showStyles:done', function _() {
-  window.removeEventListener('showStyles:done', _);
+// eslint-disable-next-line no-var
+var hotkeys = (() => {
+  let togglablesShown;
+  let togglables;
+  let enabled = false;
+  let ready = false;
 
-  let togglablesShown = true;
-  let togglables = getTogglables();
+  window.addEventListener('showStyles:done', function _() {
+    window.removeEventListener('showStyles:done', _);
+    togglablesShown = true;
+    togglables = getTogglables();
+    ready = true;
+    setState(true);
+    initHotkeyInfo();
+  });
 
-  window.addEventListener('keydown', onKeyDown);
-  initHotkeyInfo();
-  return;
+  return {setState};
+
+  function setState(newState = !enabled) {
+    if (!ready) {
+      throw new Error('hotkeys no ready');
+    }
+    if (newState !== enabled) {
+      window[`${newState ? 'add' : 'remove'}EventListener`]('keydown', onKeyDown);
+      enabled = newState;
+    }
+  }
 
   function onKeyDown(event) {
-    if (event.ctrlKey || event.altKey || event.metaKey) {
+    if (event.ctrlKey || event.altKey || event.metaKey || !enabled) {
       return;
     }
     let entry;
@@ -165,4 +183,4 @@ window.addEventListener('showStyles:done', function _() {
       });
     }
   }
-});
+})();
diff --git a/popup/popup.css b/popup/popup.css
index d058ecc2..ed852eb3 100644
--- a/popup/popup.css
+++ b/popup/popup.css
@@ -1,3 +1,12 @@
+:root {
+  --header-width: 280px;
+  --checkbox-width: 24px;
+  --name-padding-left: 40px;
+  --name-padding-right: 40px;
+  --actions-width: 75px;
+  --onoffswitch-width: 60px;
+}
+
 html, body {
   height: min-content;
 }
@@ -14,7 +23,7 @@ body {
   color: #000;
 }
 
-body > div:not(#installed) {
+body > div:not(#installed):not(#message-box):not(.colorpicker-popup) {
   margin-left: 9px;
   margin-right: 9px;
 }
@@ -216,14 +225,15 @@ html[style] .entry:nth-child(10):before {
   content: "0";
 }
 
-.entry .style-edit-link {
-  margin-right: 2px;
+.entry .actions {
+  margin-left: -1px;
+  margin-right: -1px;
 }
 
-.entry .style-edit-link,
-.entry .delete {
+.entry .actions > * {
   display: inline-block;
-  padding: 0 1px 0;
+  padding: 0 1px;
+  margin: 0 1px;
 }
 
 .not-applied .checker,
@@ -331,8 +341,8 @@ body.blocked .actions > .main-controls {
 
 /* Never shown, but can be enabled with a style */
 
-.enable,
-.disable {
+.entry .actions > .enable,
+.entry .actions > .disable {
   display: none;
 }
 
diff --git a/popup/popup.js b/popup/popup.js
index 8fdeaac6..f3c061f8 100644
--- a/popup/popup.js
+++ b/popup/popup.js
@@ -1,3 +1,5 @@
+/* global configDialog hotkeys */
+
 'use strict';
 
 let installed;
@@ -237,6 +239,7 @@ function createStyleElement({
   Object.assign(entry, {
     id: ENTRY_ID_PREFIX_RAW + style.id,
     styleId: style.id,
+    styleIsUsercss: Boolean(style.usercssData),
     className: entry.className + ' ' + (style.enabled ? 'enabled' : 'disabled'),
     onmousedown: handleEvent.maybeEdit,
   });
@@ -267,9 +270,18 @@ function createStyleElement({
     }
   });
 
+  const config = $('.configure', entry);
+  if (!style.usercssData && style.updateUrl && style.updateUrl.includes('?') && style.url) {
+    config.href = style.url;
+    config.target = '_blank';
+  } else if (!style.usercssData || !Object.keys(style.usercssData.vars || {}).length) {
+    config.style.display = 'none';
+  }
+
   $('.enable', entry).onclick = handleEvent.toggle;
   $('.disable', entry).onclick = handleEvent.toggle;
   $('.delete', entry).onclick = handleEvent.delete;
+  $('.configure', entry).onclick = handleEvent.configure;
 
   invokeOrPostpone(!postponeDetect, detectSloppyRegexps, {entry, style});
 
@@ -339,6 +351,18 @@ Object.assign(handleEvent, {
     }
   },
 
+  configure(event) {
+    const {styleId, styleIsUsercss} = handleEvent.getClickedStyleElement(event);
+    if (styleIsUsercss) {
+      getStylesSafe({id: styleId}).then(([style]) => {
+        hotkeys.setState(false);
+        configDialog(style).then(() => {
+          hotkeys.setState(true);
+        });
+      });
+    }
+  },
+
   indicator(event) {
     const entry = handleEvent.getClickedStyleElement(event);
     const info = template.regexpProblemExplanation.cloneNode(true);
diff --git a/vendor-overwrites/colorpicker/colorpicker.js b/vendor-overwrites/colorpicker/colorpicker.js
index f18e0c85..4668406c 100644
--- a/vendor-overwrites/colorpicker/colorpicker.js
+++ b/vendor-overwrites/colorpicker/colorpicker.js
@@ -218,8 +218,11 @@
     setFromHexLettercaseElement();
   }
 
-  function hide() {
+  function hide({notify = true} = {}) {
     if (shown) {
+      if (notify) {
+        colorpickerCallback('');
+      }
       unregisterEvents();
       focusNoScroll(prevFocusedElement);
       $root.remove();
@@ -550,8 +553,11 @@
   }
 
   function onMouseUp(event) {
-    if (releaseMouse(event, ['saturation', 'hue', 'opacity']) &&
-        !event.target.closest('.codemirror-colorview, .colorpicker-popup, .CodeMirror')) {
+    releaseMouse(event, ['saturation', 'hue', 'opacity']);
+  }
+
+  function onMouseDown(event) {
+    if (event.button === 0 && !event.target.closest('.colorpicker-popup')) {
       hide();
     }
   }
@@ -592,7 +598,7 @@
           colorpickerCallback(e.which === 27 ? '' : undefined);
           e.preventDefault();
           e.stopPropagation();
-          hide();
+          hide({notify: false});
           break;
       }
     }
@@ -660,6 +666,7 @@
 
   function registerEvents() {
     window.addEventListener('keydown', onKeyDown, true);
+    window.addEventListener('mousedown', onMouseDown, true);
     window.addEventListener('close-colorpicker-popup', onCloseRequest, true);
     $root.addEventListener('mouseleave', snooze);
     $root.addEventListener('mouseenter', stopSnoozing);
@@ -681,6 +688,7 @@
 
   function unregisterEvents() {
     window.removeEventListener('keydown', onKeyDown, true);
+    window.removeEventListener('mousedown', onMouseDown, true);
     window.removeEventListener('close-colorpicker-popup', hide, true);
     $root.removeEventListener('mouseleave', snooze);
     $root.removeEventListener('mouseenter', stopSnoozing);
@@ -940,6 +948,9 @@
       realColor.g = Math.round(g * q1 + realColor.g * q2);
       realColor.b = Math.round(b * q1 + realColor.b * q2);
       realColor.a = mixedA;
+      if (Math.abs(realColor.a - 1) < 1e-3) {
+        break;
+      }
     }
     // https://www.w3.org/TR/AERT#color-contrast
     const {r, g, b} = realColor;
diff --git a/vendor-overwrites/csslint/csslint-worker.js b/vendor-overwrites/csslint/csslint-worker.js
index 03d92460..c5757539 100644
--- a/vendor-overwrites/csslint/csslint-worker.js
+++ b/vendor-overwrites/csslint/csslint-worker.js
@@ -3181,6 +3181,17 @@ Parser.prototype = function() {
              * @private
              */
             _unexpectedToken: function(token) {
+                for (let i = tokenStream._ltIndex - 1; i >= 0; i--) {
+                    const {type, value} = tokenStream._lt[i];
+                    if (type === tokenStream._tokenData.S) {
+                        // NOP
+                    } else if (type === tokenStream._tokenData.COMMENT &&
+                            value[2] === '[' && value[3] === '[' && value.endsWith(']]*/')) {
+                        return;
+                    } else {
+                        break;
+                    }
+                }
                 throw new SyntaxError("Unexpected token '" + token.value + "' at line " + token.startLine + ", col " + token.startCol + ".", token.startLine, token.startCol);
             },
 
@@ -7148,7 +7159,7 @@ TokenStreamBase.prototype = {
             if (tokenTypes.includes(tt)) {
                 return true;
             }
-        } while (tt === 4 && this.LA(0) !== 0);
+        } while (tt === this._tokenData.COMMENT && this.LA(0) !== 0);
 
         //no match found, put the token back
         this.unget();
@@ -10967,25 +10978,6 @@ CSSLint.addFormatter({
     }
 });
 
-if (!CSSLint.suppressUsoVarError) {
-  CSSLint.suppressUsoVarError = true;
-  parserlib.css.Tokens[parserlib.css.Tokens.COMMENT].hide = false;
-  const isUsoVar = ({value}) => value.startsWith('/*[[') && value.endsWith(']]*/');
-  CSSLint.addRule({
-    id: 'uso-vars',
-    init(parser, reporter) {
-      parser.addListener('error', function ({message, line, col}) {
-        if (!isUsoVar(this._tokenStream._token)) {
-          const {_lt, _ltIndex: i} = this._tokenStream;
-          if (i < 2 || !_lt.slice(0, i - 1).reverse().some(isUsoVar)) {
-            reporter.error(message, line, col);
-          }
-        }
-      });
-    },
-  });
-}
-
 self.onmessage = ({data: {action = 'run', code, config}}) => {
   switch (action) {
 
@@ -11000,8 +10992,6 @@ self.onmessage = ({data: {action = 'run', code, config}}) => {
       return;
 
     case 'run':
-      Object.defineProperty(config, 'errors', {get: () => 0, set: () => 0});
-      config['uso-vars'] = 1;
       self.postMessage(CSSLint.verify(code, config).messages.map(m => {
         // the functions are non-tranferable and we need only an id
         m.rule = {id: m.rule.id};