Implement a no-dark-mode component. (mathjax/MathJax#3502)

components/mjs/source.js

@@ -82,6 +82,7 @@ export const source = {
   '[mathmaps]': `${src}/../../bundle/sre/mathmaps`,
   'ui/lazy': `${src}/ui/lazy/lazy.js`,
   'ui/menu': `${src}/ui/menu/menu.js`,
+  'ui/no-dark-mode': `${src}/ui/nodarkmode/nodarkmode.js`,
   'ui/safe': `${src}/ui/safe/safe.js`,
   'mml-chtml': `${src}/mml-chtml/mml-chtml.js`,
   'mml-chtml-nofont': `${src}/mml-chtml-nofont/mml-chtml-nofont.js`,

components/mjs/ui/no-dark-mode/config.json

@@ -0,0 +1,5 @@
+{
+  "webpack": {
+    "name": "ui/no-dark-mode"
+  }
+}

components/mjs/ui/no-dark-mode/no-dark-mode.js

@@ -0,0 +1,7 @@
+import {VERSION} from '#js/components/version.js';
+import '#js/ui/no-dark-mode/no-dark-mode.js';
+
+if (MathJax.loader) {
+  MathJax.loader.checkVersion('ui/no-dark-mode', VERSION, 'extension');
+}
+

ts/ui/no-dark-mode/no-dark-mode.ts

@@ -0,0 +1,97 @@
+/*************************************************************
+ *
+ *  Copyright (c) 2026 The MathJax Consortium
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+/**
+ * @file  An extension to disable dark mode for sites that don't support that
+ *
+ * @author dpvc@mathjax.org (Davide Cervone)
+ */
+
+import { MathJax } from '../../components/global.js';
+import { MathJaxObject } from '../../components/startup.js';
+import { AbstractHandler } from '../../core/Handler.js';
+
+[
+  [
+    MathJax._.ui?.dialog,
+    'core',
+    () => {
+      const { DraggableDialog } = MathJax._.ui.dialog.DraggableDialog;
+      delete DraggableDialog.styles['@media (prefers-color-scheme: dark)'];
+    },
+  ],
+
+  [
+    MathJax._.a11y?.explorer,
+    'a11y/explorer',
+    () => {
+      const Region = MathJax._.a11y.explorer.Region;
+      for (const region of ['LiveRegion', 'HoverRegion', 'ToolTip']) {
+        Region[region].style.styles['@media (prefers-color-scheme: dark)'] = {};
+      }
+      Region.LiveRegion.style.styles['@media (prefers-color-scheme: dark)'][
+        'mjx-ignore'
+      ] = { ignore: 1 };
+      (MathJax as MathJaxObject).startup.extendHandler(
+        (handler: AbstractHandler<any, any, any>) => {
+          delete (handler.documentClass as any).speechStyles[
+            '@media (prefers-color-scheme: dark) /* explorer */'
+          ];
+          return handler;
+        }
+      );
+    },
+  ],
+
+  [
+    MathJax._.output?.chtml,
+    'output/chtml',
+    () => {
+      const { CHTML } = MathJax._.output.chtml_ts;
+      delete CHTML.commonStyles['@media (prefers-color-scheme: dark)'];
+      const { ChtmlMaction } = MathJax._.output.chtml.Wrappers.maction;
+      delete ChtmlMaction.styles[
+        '@media (prefers-color-scheme: dark) /* chtml maction */'
+      ];
+    },
+  ],
+
+  [
+    MathJax._.output?.svg,
+    'output/svg',
+    () => {
+      const { SVG } = MathJax._.output.svg_ts;
+      delete SVG.commonStyles['@media (prefers-color-scheme: dark)'];
+      const { SvgMaction } = MathJax._.output.svg.Wrappers.maction;
+      delete SvgMaction.styles[
+        '@media (prefers-color-scheme: dark) /* svg maction */'
+      ];
+    },
+  ],
+].forEach(([immediate, extension, ready]) => {
+  if (immediate) {
+    ready();
+  } else {
+    const config = MathJax.config.loader;
+    config[extension] ??= {};
+    const check = config[extension].checkReady;
+    config[extension].checkReady = async () => {
+      if (check) await check();
+      return ready();
+    };
+  }
+});