diff --git a/edit.html b/edit.html
index da93b705..897e9601 100644
--- a/edit.html
+++ b/edit.html
@@ -95,6 +95,7 @@
     <script src="edit/linter-meta.js"></script>
     <script src="edit/linter-help-dialog.js"></script>
     <script src="edit/linter-report.js"></script>
+    <script src="edit/linter-config-dialog.js"></script>
 
     <script src="edit/editor-worker.js"></script>
 
diff --git a/edit/linter-config-dialog.js b/edit/linter-config-dialog.js
new file mode 100644
index 00000000..d4bde537
--- /dev/null
+++ b/edit/linter-config-dialog.js
@@ -0,0 +1,196 @@
+/* global cacheFn editorWorker stylelint csslint showCodeMirrorPopup loadScript messageBox */
+'use strict';
+
+(() => {
+  document.addEventListener('DOMContentLoaded', () => {
+    $('#linter-settings').addEventListener('click', showLintConfig);
+  }, {once: true});
+
+  function stringifyConfig(config) {
+    return JSON.stringify(config, null, 2)
+      .replace(/,\n\s+\{\n\s+("severity":\s"\w+")\n\s+\}/g, ', {$1}');
+  }
+
+  function showLinterErrorMessage(title, contents, popup) {
+    messageBox({
+      title,
+      contents,
+      className: 'danger center lint-config',
+      buttons: [t('confirmOK')],
+    }).then(() => popup && popup.codebox && popup.codebox.focus());
+  }
+
+  function showLintConfig() {
+    const linter = $('#editor.linter').value;
+    if (!linter) {
+      return;
+    }
+    const storageName = linter === 'styleint' ? 'editorStylelintConfig' : 'editorCSSLintConfig';
+    const getRules = cacheFn(linter === 'stylelint' ?
+      editorWorker.getStylelintRules : editorWorker.getCsslintRules);
+    const linterTitle = linter === 'stylelint' ? 'Stylelint' : 'CSSLint';
+    const defaultConfig = stringifyConfig(
+      linter === 'stylelint' ? stylelint.DEFAULT : csslint.DEFAULT
+    );
+    const title = t('linterConfigPopupTitle', linterTitle);
+    const popup = showCodeMirrorPopup(title, null, {
+      lint: false,
+      extraKeys: {'Ctrl-Enter': save},
+      hintOptions: {hint},
+    });
+    $('.contents', popup).appendChild(makeFooter());
+
+    let cm = popup.codebox;
+    cm.focus();
+    chromeSync.getLZValue(storageName).then(config => {
+      cm.setValue(config ? stringifyConfig(config) : defaultConfig);
+      cm.clearHistory();
+      cm.markClean();
+      updateButtonState();
+    });
+    cm.on('changes', updateButtonState);
+
+    cm.rerouteHotkeys(false);
+    window.addEventListener('closeHelp', function _() {
+      window.removeEventListener('closeHelp', _);
+      cm.rerouteHotkeys(true);
+      cm = null;
+    });
+
+    loadScript([
+      '/vendor/codemirror/mode/javascript/javascript.js',
+      '/vendor/codemirror/addon/lint/json-lint.js',
+      '/vendor/jsonlint/jsonlint.js'
+    ]).then(() => {
+      cm.setOption('mode', 'application/json');
+      cm.setOption('lint', true);
+    });
+
+    function findInvalidRules(config, linter) {
+      return getRules()
+        .then(rules => {
+          if (linter === 'stylelint') {
+            return Object.keys(config.rules).filter(k => !rules.hasOwnProperty(k));
+          }
+          const ruleSet = new Set(rules.map(r => r.id));
+          return Object.keys(config).filter(k => !ruleSet.has(k));
+        });
+    }
+
+    function makeFooter() {
+      return $create('div', [
+        $create('p', [
+          $createLink(
+            linter === 'stylelint'
+              ? 'https://stylelint.io/user-guide/rules/'
+              : 'https://github.com/CSSLint/csslint/wiki/Rules-by-ID',
+            t('linterRulesLink')),
+          linter === 'csslint' ? ' ' + t('linterCSSLintSettings') : '',
+        ]),
+        $create('.buttons', [
+          $create('button.save', {onclick: save, title: 'Ctrl-Enter'}, t('styleSaveLabel')),
+          $create('button.cancel', {onclick: cancel}, t('confirmClose')),
+          $create('button.reset', {onclick: reset, title: t('linterResetMessage')}, t('genericResetLabel')),
+        ]),
+      ]);
+    }
+
+    function save(event) {
+      if (event instanceof Event) {
+        event.preventDefault();
+      }
+      const json = tryJSONparse(cm.getValue());
+      if (!json) {
+        showLinterErrorMessage(linter, t('linterJSONError'), popup);
+        cm.focus();
+        return;
+      }
+      findInvalidRules(json, linter).then(invalid => {
+        if (invalid.length) {
+          showLinterErrorMessage(linter, [
+            t('linterInvalidConfigError'),
+            $create('ul', invalid.map(name => $create('li', name))),
+          ], popup);
+          return;
+        }
+        chromeSync.setLZValue(storageName, json);
+        cm.markClean();
+        cm.focus();
+        updateButtonState();
+      });
+    }
+
+    function reset(event) {
+      event.preventDefault();
+      cm.setValue(defaultConfig);
+      cm.focus();
+      updateButtonState();
+    }
+
+    function cancel(event) {
+      event.preventDefault();
+      $('.dismiss').dispatchEvent(new Event('click'));
+    }
+
+    function updateButtonState() {
+      $('.save', popup).disabled = cm.isClean();
+      $('.reset', popup).disabled = cm.getValue() === defaultConfig;
+      $('.cancel', popup).textContent = t(cm.isClean() ? 'confirmClose' : 'confirmCancel');
+    }
+
+    function hint(cm) {
+      return getRules().then(rules => {
+        let ruleIds, options;
+        if (linter === 'stylelint') {
+          ruleIds = Object.keys(rules);
+          options = rules;
+        } else {
+          ruleIds = rules.map(r => r.id);
+          options = {};
+        }
+        const cursor = cm.getCursor();
+        const {start, end, string, type, state: {lexical}} = cm.getTokenAt(cursor);
+        const {line, ch} = cursor;
+
+        const quoted = string.startsWith('"');
+        const leftPart = string.slice(quoted ? 1 : 0, ch - start).trim();
+        const depth = getLexicalDepth(lexical);
+
+        const search = cm.getSearchCursor(/"([-\w]+)"/, {line, ch: start - 1});
+        let [, prevWord] = search.find(true) || [];
+        let words = [];
+
+        if (depth === 1 && linter === 'stylelint') {
+          words = quoted ? ['rules'] : [];
+        } else if ((depth === 1 || depth === 2) && type && type.includes('property')) {
+          words = ruleIds;
+        } else if (depth === 2 || depth === 3 && lexical.type === ']') {
+          words = !quoted ? ['true', 'false', 'null'] :
+            ruleIds.includes(prevWord) && (options[prevWord] || [])[0] || [];
+        } else if (depth === 4 && prevWord === 'severity') {
+          words = ['error', 'warning'];
+        } else if (depth === 4) {
+          words = ['ignore', 'ignoreAtRules', 'except', 'severity'];
+        } else if (depth === 5 && lexical.type === ']' && quoted) {
+          while (prevWord && !ruleIds.includes(prevWord)) {
+            prevWord = (search.find(true) || [])[1];
+          }
+          words = (options[prevWord] || []).slice(-1)[0] || ruleIds;
+        }
+        return {
+          list: words.filter(word => word.startsWith(leftPart)),
+          from: {line, ch: start + (quoted ? 1 : 0)},
+          to: {line, ch: string.endsWith('"') ? end - 1 : end},
+        };
+      });
+    }
+
+    function getLexicalDepth(lexicalState) {
+      let depth = 0;
+      while ((lexicalState = lexicalState.prev)) {
+        depth++;
+      }
+      return depth;
+    }
+  }
+})();
diff --git a/edit/linter-report.js b/edit/linter-report.js
index 4800223a..370c0d2a 100644
--- a/edit/linter-report.js
+++ b/edit/linter-report.js
@@ -33,7 +33,6 @@ var linterReport = (() => { // eslint-disable-line no-var
 
   document.addEventListener('DOMContentLoaded', () => {
     $('#lint-help').addEventListener('click', helpDialog.show);
-    $('#linter-settings').addEventListener('click', showLintConfig);
   }, {once: true});
 
   return {refresh};
@@ -152,6 +151,4 @@ var linterReport = (() => { // eslint-disable-line no-var
     cm.focus();
     cm.setSelection(anno.from);
   }
-
-  function showLintConfig() {}
 })();
diff --git a/edit/util.js b/edit/util.js
index f44d5d95..a796067b 100644
--- a/edit/util.js
+++ b/edit/util.js
@@ -121,3 +121,16 @@ function sectionsToMozFormat(style) {
 function clipString(str, limit = 100) {
   return str.length <= limit ? str : str.substr(0, limit) + '...';
 }
+
+// cache the first call
+function cacheFn(fn) {
+  let cached = false;
+  let result;
+  return (...args) => {
+    if (!cached) {
+      result = fn(...args);
+      cached = true;
+    }
+    return result;
+  };
+}