Styling the editor elements

The structural styling of the component is done through CSS module class names, which have auto-generated suffixes that can change between versions. The key DOM elements of the component have "public" CSS classes that you can safely target with your own CSS.

  • mdxeditor - Set at the root element of the editor and the container for the pop-ups/tooltips.
  • mdxeditor-popup-container assigned to the popup container. Use this if you're using MDXEditor with a framework like MUI and you need to override the z-index of the popups.
  • mdxeditor-toolbar - The toolbar container.
  • mdxeditor-root-contenteditable - The root contentEditable element, managed by Lexical.
  • mdxeditor-diff-source-wrapper - If you're using the diffSourcePlugin, it injects an element around the editor so that you can toggle between the rich text and source / diff mode. This CSS class is assigned to that wrapper.
  • mdxeditor-rich-text-editor, mdxeditor-source-editor, mdxeditor-diff-editor - If you're using the diffSourcePlugin, these classes are assigned to the rich text, source and diff editor root elements, respectively.
  • mdxeditor-select-content - assigned to the Radix UI Select.Content component - useful if you want to style the select dropdowns, for example to limit their size on smaller viewports.

Customizing the editor colors

The editor UI (toolbar, dialogs, etc) colors and fonts are defined as CSS variables attached to the editor root element. The color variables follow the Radix semantic aliasing convention.

The example below swaps the editor gray/blue colors with tomato/mauve. In addition, assigning the dark-theme class to the editor also flips it to dark mode (this is a feature of the Radix colors).

@import url('@radix-ui/colors/tomato-dark.css');
@import url('@radix-ui/colors/mauve-dark.css');

.dark-editor {
  --accentBase: var(--tomato-1);
  --accentBgSubtle: var(--tomato-2);
  --accentBg: var(--tomato-3);
  --accentBgHover: var(--tomato-4);
  --accentBgActive: var(--tomato-5);
  --accentLine: var(--tomato-6);
  --accentBorder: var(--tomato-7);
  --accentBorderHover: var(--tomato-8);
  --accentSolid: var(--tomato-9);
  --accentSolidHover: var(--tomato-10);
  --accentText: var(--tomato-11);
  --accentTextContrast: var(--tomato-12);

  --baseBase: var(--mauve-1);
  --baseBgSubtle: var(--mauve-2);
  --baseBg: var(--mauve-3);
  --baseBgHover: var(--mauve-4);
  --baseBgActive: var(--mauve-5);
  --baseLine: var(--mauve-6);
  --baseBorder: var(--mauve-7);
  --baseBorderHover: var(--mauve-8);
  --baseSolid: var(--mauve-9);
  --baseSolidHover: var(--mauve-10);
  --baseText: var(--mauve-11);
  --baseTextContrast: var(--mauve-12);

  --admonitionTipBg: var(--cyan4);
  --admonitionTipBorder: var(--cyan8);
  --admonitionInfoBg: var(--grass4);
  --admonitionInfoBorder: var(--grass8);

  --admonitionCautionBg: var(--amber4);
  --admonitionCautionBorder: var(--amber8);

  --admonitionDangerBg: var(--red4);
  --admonitionDangerBorder: var(--red8);

  --admonitionNoteBg: var(--mauve-4);
  --admonitionNoteBorder: var(--mauve-8);

  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

  color: var(--baseText);
  --basePageBg: black;
  background: var(--basePageBg);
export function CustomTheming() {
  return (
      className="dark-theme dark-editor" 
        toolbarPlugin({ toolbarContents: () => <KitchenSinkToolbar /> }),
        codeBlockPlugin({ defaultCodeBlockLanguage: 'txt' }),
        sandpackPlugin({ sandpackConfig: virtuosoSampleSandpackConfig }),
        codeMirrorPlugin({ codeBlockLanguages: { js: 'JavaScript', css: 'CSS', txt: 'text', tsx: 'TypeScript' } }),
        directivesPlugin({ directiveDescriptors: [YoutubeDirectiveDescriptor, AdmonitionDirectiveDescriptor] }),
        diffSourcePlugin({ viewMode: 'rich-text', diffMarkdown: 'boo' }),