feat(builder): CodeMirror 6 code editor for HTML/CSS/JS with lazy loading

Replaces the plain single-line input (HtmlBlock's `code` prop, via GenericPropsEditor) and the plain <textarea> (HeadCodeModal's site-wide head code) with a proper syntax-highlighted, tab-completing code editor. - New src/ui/CodeEditor.tsx: reusable CodeMirror 6 editor (state/view/ commands/autocomplete/language/lang-html/lang-css/lang-javascript/ theme-one-dark). All @codemirror/* packages are pulled in via a single dynamic import() inside the component so they land in separate lazy chunks instead of the main bundle -- confirmed via `npm run build`: main editor.js grew by only ~5.5KB (657KB -> 663KB raw) while ~570KB of CodeMirror source split into index*.js chunks that only load when a code editor modal is actually opened. While that import is in flight, or if it ever fails, the component renders a plain <textarea> so typing never breaks. - GenericPropsEditor.tsx: special-cases the `code` prop (used only by HtmlBlock today) into an "Edit HTML" button that opens the CodeEditor in a modal (language="html"), instead of rendering it as a single-line text input alongside the component's other string props. - HeadCodeModal.tsx: swaps its <textarea> for CodeEditor (language="html" -- head code is HTML with embedded <script>/<style>), keeping the existing SiteDesignContext.updateDesign({ headCode }) wiring. GuidedStyles.tsx untouched: HtmlBlock's displayName ("HTML") already matches GuidedStyles' `isUtility` regex and routes to GenericPropsEditor, so no dispatcher change was needed. HtmlBlock.tsx untouched: purifyHtml/toHtml sanitization is unchanged, as specified. Skipped the optional AnimationControl/VisibilityControl addition -- HtmlBlock has no dedicated StylePanel (it shares GenericPropsEditor with Divider/Spacer/every unmatched type), and doing it well would mean adding real Animation/Visibility widgets to that shared editor for every consumer, which is a bigger change than "trivial" for this package's scope. Tests: CodeEditor.test.tsx and HeadCodeModal.test.tsx both exploit the fact that dynamic import() always resolves on a later microtask, so asserting against the DOM immediately after the initial synchronous render deterministically exercises the <textarea> fallback path (value display, onChange wiring, language prop plumbing) without needing to mock @codemirror/*. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-14 06:42:59 -07:00
13 changed files with 528 additions and 535 deletions
@@ -52,69 +52,3 @@ describe('ButtonLink.toHtml text escaping (attacker-controlled `text` prop)', ()
    expect(html).toContain('>Click Me</a>');
  });
 });
-
-describe('ButtonLink.toHtml hover state (scoped <style> block)', () => {
-  test('no hover props -- no <style> block, no class added', () => {
-    const { html } = toHtml({ href: '#', text: 'x' }, '', 'node-1');
-    expect(html).not.toContain('<style>');
-    expect(html).not.toContain('class=');
-  });
-
-  test('hoverBg/hoverColor emit a scoped :hover rule scoped to the node id', () => {
-    const { html } = toHtml({ href: '#', text: 'x', hoverBg: '#111111', hoverColor: '#eeeeee' }, '', 'node-42');
-    expect(html).toMatch(/<style>\.btn_[a-z0-9]+:hover\{background-color:#111111;color:#eeeeee\}<\/style>/);
-    expect(html).toMatch(/class="btn_[a-z0-9]+"/);
-  });
-
-  test('two different node ids produce different scope classes (no collision)', () => {
-    const a = toHtml({ href: '#', text: 'x', hoverBg: '#111111' }, '', 'node-a').html;
-    const b = toHtml({ href: '#', text: 'x', hoverBg: '#111111' }, '', 'node-b').html;
-    const scopeOf = (html: string) => html.match(/btn_[a-z0-9]+/)?.[0];
-    expect(scopeOf(a)).toBeTruthy();
-    expect(scopeOf(a)).not.toBe(scopeOf(b));
-  });
-
-  test('an XSS breakout attempt in hoverBg cannot close the <style> element', () => {
-    const malicious = '</style><script>alert(1)</script>';
-    const { html } = toHtml({ href: '#', text: 'x', hoverBg: malicious }, '', 'node-1');
-    expect(html).not.toContain('</style><script>');
-    expect(html).not.toContain('<script>alert(1)</script>');
-  });
-
-  test('a rule-breakout attempt in hoverColor cannot inject a second selector/rule', () => {
-    const malicious = 'red;}body{background:red';
-    const { html } = toHtml({ href: '#', text: 'x', hoverColor: malicious }, '', 'node-1');
-    expect(html).not.toContain('}body{');
-    expect(html).not.toContain(';}');
-    // The whole export is still exactly one <style> element -- no new rule
-    // or element was opened by the malicious value.
-    expect((html.match(/<style>/g) || []).length).toBe(1);
-    expect((html.match(/<\/style>/g) || []).length).toBe(1);
-  });
-});
-
-describe('ButtonLink.craft.props exposes target + hover + box-model + animation/visibility', () => {
-  test('target defaults to _self, hoverBg/hoverColor blank', () => {
-    const props = (ButtonLink as any).craft.props;
-    expect(props.target).toBe('_self');
-    expect(props.hoverBg).toBe('');
-    expect(props.hoverColor).toBe('');
-  });
-
-  test('animation, animationDelay, hideOnDesktop/Tablet/Mobile are present with blank/false defaults', () => {
-    const props = (ButtonLink as any).craft.props;
-    expect(props.animation).toBe('');
-    expect(props.animationDelay).toBe('0');
-    expect(props.hideOnDesktop).toBe(false);
-    expect(props.hideOnTablet).toBe(false);
-    expect(props.hideOnMobile).toBe(false);
-  });
-
-  test('style carries blank/default box-model keys', () => {
-    const style = (ButtonLink as any).craft.props.style;
-    expect(style).toHaveProperty('marginTop');
-    expect(style.border).toBe('none');
-    expect(style.boxShadow).toBe('none');
-    expect(style.opacity).toBe('1');
-  });
-});
@@ -1,24 +1,13 @@
 import React, { CSSProperties } from 'react';
 import { useNode, UserComponent } from '@craftjs/core';
 import { cssPropsToString } from '../../utils/style-helpers';
-import { escapeHtml, escapeAttr, safeUrl, cssValue, scopeId } from '../../utils/escape';
+import { escapeHtml, escapeAttr, safeUrl } from '../../utils/escape';

 interface ButtonLinkProps {
  text?: string;
  href?: string;
  target?: '_self' | '_blank';
  style?: CSSProperties;
-  /** Background color applied on `:hover` via a scoped `<style>` block
-   *  (editor preview does not show hover state -- only the published
-   *  export). Blank means "no hover background override". */
-  hoverBg?: string;
-  /** Text color applied on `:hover`, same scoped `<style>` block. */
-  hoverColor?: string;
-  animation?: string;
-  animationDelay?: string;
-  hideOnDesktop?: boolean;
-  hideOnTablet?: boolean;
-  hideOnMobile?: boolean;
 }

 export const ButtonLink: UserComponent<ButtonLinkProps> = ({
@@ -26,8 +15,6 @@ export const ButtonLink: UserComponent<ButtonLinkProps> = ({
  href = '#',
  target = '_self',
  style = {},
-  hoverBg = '',
-  hoverColor = '',
 }) => {
  const {
    connectors: { connect, drag },
@@ -36,8 +23,6 @@ export const ButtonLink: UserComponent<ButtonLinkProps> = ({
    selected: node.events.selected,
  }));

-  const [hovered, setHovered] = React.useState(false);
-
  return (
    <a
      ref={(ref: HTMLAnchorElement | null) => { if (ref) connect(drag(ref)); }}
@@ -47,16 +32,12 @@ export const ButtonLink: UserComponent<ButtonLinkProps> = ({
        // Prevent navigation inside editor
        e.preventDefault();
      }}
-      onMouseEnter={() => setHovered(true)}
-      onMouseLeave={() => setHovered(false)}
      style={{
        display: 'inline-block',
        textDecoration: 'none',
        cursor: 'pointer',
        outline: selected ? '2px solid #3b82f6' : 'none',
        ...style,
-        ...(hovered && hoverBg ? { backgroundColor: hoverBg } : {}),
-        ...(hovered && hoverColor ? { color: hoverColor } : {}),
      }}
    >
      {text}
@@ -72,8 +53,6 @@ ButtonLink.craft = {
    text: 'Click Me',
    href: '#',
    target: '_self',
-    hoverBg: '',
-    hoverColor: '',
    style: {
      backgroundColor: '#3b82f6',
      color: '#ffffff',
@@ -82,15 +61,7 @@ ButtonLink.craft = {
      fontWeight: '600',
      fontSize: '16px',
      border: 'none',
-      marginTop: '', marginRight: '', marginBottom: '', marginLeft: '',
-      boxShadow: 'none',
-      opacity: '1',
    },
-    animation: '',
-    animationDelay: '0',
-    hideOnDesktop: false,
-    hideOnTablet: false,
-    hideOnMobile: false,
  },
  rules: {
    canDrag: () => true,
@@ -101,7 +72,7 @@ ButtonLink.craft = {

 /* ---------- HTML export ---------- */

-(ButtonLink as any).toHtml = (props: ButtonLinkProps, _childrenHtml: string, nodeId?: string) => {
+(ButtonLink as any).toHtml = (props: ButtonLinkProps, _childrenHtml: string) => {
  const styleStr = cssPropsToString({
    display: 'inline-block',
    textDecoration: 'none',
@@ -109,28 +80,7 @@ ButtonLink.craft = {
  });
  const escapedText = escapeHtml(props.text || '');
  const targetAttr = props.target === '_blank' ? ' target="_blank" rel="noopener noreferrer"' : '';
-
-  // Scoped hover style -- same pattern as Navbar/Menu: a deterministic,
-  // per-node class (via scopeId) avoids two ButtonLink instances on the
-  // same page colliding on a shared `.btn-link:hover` rule. hoverBg/
-  // hoverColor are sanitized through cssValue -- they land inside a
-  // `<style>` element, the worst-case XSS sink (an unescaped `<`/`>` or
-  // `{`/`}` could close the rule/element and open a `<script>`).
-  const hoverBg = cssValue(props.hoverBg);
-  const hoverColor = cssValue(props.hoverColor);
-  let hoverCss = '';
-  let cls = '';
-  if (hoverBg || hoverColor) {
-    const scope = scopeId(nodeId, (props.href || '') + (props.text || ''), 'btn');
-    cls = ` class="${scope}"`;
-    const decls = [
-      hoverBg ? `background-color:${hoverBg}` : '',
-      hoverColor ? `color:${hoverColor}` : '',
-    ].filter(Boolean).join(';');
-    hoverCss = `<style>.${scope}:hover{${decls}}</style>`;
-  }
-
  return {
-    html: `${hoverCss}<a href="${escapeAttr(safeUrl(props.href || '#'))}"${targetAttr}${cls}${styleStr ? ` style="${styleStr}"` : ''}>${escapedText}</a>`,
+    html: `<a href="${escapeAttr(safeUrl(props.href || '#'))}"${targetAttr}${styleStr ? ` style="${styleStr}"` : ''}>${escapedText}</a>`,
  };
 };
@@ -56,54 +56,3 @@ describe('Heading.toHtml text escaping (attacker-controlled `text` prop)', () =>
    expect(html).toBe('<h2>Hello world</h2>');
  });
 });
-
-describe('Heading.toHtml typography depth (line-height/letter-spacing/transform/style/decoration)', () => {
-  test('line-height, letter-spacing, text-transform all flow into the style attribute', () => {
-    const { html } = toHtml({
-      text: 'x',
-      level: 'h2',
-      style: { lineHeight: '1.25', letterSpacing: '0.05em', textTransform: 'uppercase' },
-    }, '');
-    expect(html).toContain('line-height:1.25');
-    expect(html).toContain('letter-spacing:0.05em');
-    expect(html).toContain('text-transform:uppercase');
-  });
-
-  test('italic + underline toggles emit font-style and text-decoration', () => {
-    const { html } = toHtml({
-      text: 'x',
-      level: 'h2',
-      style: { fontStyle: 'italic', textDecoration: 'underline' },
-    }, '');
-    expect(html).toContain('font-style:italic');
-    expect(html).toContain('text-decoration:underline');
-  });
-
-  test('a custom font-size (not one of the presets) still flows through', () => {
-    const { html } = toHtml({ text: 'x', level: 'h2', style: { fontSize: '42px' } }, '');
-    expect(html).toContain('font-size:42px');
-  });
-});
-
-describe('Heading.craft.props exposes the box-model + animation/visibility rollout', () => {
-  test('animation, animationDelay, hideOnDesktop/Tablet/Mobile are present with blank/false defaults', () => {
-    const props = (Heading as any).craft.props;
-    expect(props.animation).toBe('');
-    expect(props.animationDelay).toBe('0');
-    expect(props.hideOnDesktop).toBe(false);
-    expect(props.hideOnTablet).toBe(false);
-    expect(props.hideOnMobile).toBe(false);
-  });
-
-  test('style carries blank/default box-model + typography-depth keys', () => {
-    const style = (Heading as any).craft.props.style;
-    expect(style).toHaveProperty('marginTop');
-    expect(style).toHaveProperty('paddingTop');
-    expect(style).toHaveProperty('lineHeight');
-    expect(style).toHaveProperty('letterSpacing');
-    expect(style).toHaveProperty('textTransform');
-    expect(style.border).toBe('none');
-    expect(style.boxShadow).toBe('none');
-    expect(style.opacity).toBe('1');
-  });
-});
@@ -100,22 +100,7 @@ Heading.craft = {
      fontFamily: 'Inter, sans-serif',
      color: '#1f2937',
      marginBottom: '16px',
-      lineHeight: '',
-      letterSpacing: '',
-      textTransform: '' as CSSProperties['textTransform'],
-      fontStyle: '' as CSSProperties['fontStyle'],
-      textDecoration: '',
-      marginTop: '', marginRight: '', marginLeft: '',
-      paddingTop: '', paddingRight: '', paddingBottom: '', paddingLeft: '',
-      border: 'none',
-      boxShadow: 'none',
-      opacity: '1',
    },
-    animation: '',
-    animationDelay: '0',
-    hideOnDesktop: false,
-    hideOnTablet: false,
-    hideOnMobile: false,
  },
  rules: {
    canDrag: () => true,
@@ -20,48 +20,3 @@ describe('TextBlock.toHtml text escaping (attacker-controlled `text` prop)', ()
    expect(html).toBe('<p>Hello world</p>');
  });
 });
-
-describe('TextBlock.toHtml typography depth (line-height/letter-spacing/transform/style/decoration)', () => {
-  test('line-height, letter-spacing, text-transform all flow into the style attribute', () => {
-    const { html } = toHtml({
-      text: 'x',
-      style: { lineHeight: '1.75', letterSpacing: '-0.02em', textTransform: 'capitalize' },
-    }, '');
-    expect(html).toContain('line-height:1.75');
-    expect(html).toContain('letter-spacing:-0.02em');
-    expect(html).toContain('text-transform:capitalize');
-  });
-
-  test('italic + underline toggles emit font-style and text-decoration', () => {
-    const { html } = toHtml({ text: 'x', style: { fontStyle: 'italic', textDecoration: 'underline' } }, '');
-    expect(html).toContain('font-style:italic');
-    expect(html).toContain('text-decoration:underline');
-  });
-
-  test('a custom font-size (not one of the presets) still flows through', () => {
-    const { html } = toHtml({ text: 'x', style: { fontSize: '19px' } }, '');
-    expect(html).toContain('font-size:19px');
-  });
-});
-
-describe('TextBlock.craft.props exposes the box-model + animation/visibility rollout', () => {
-  test('animation, animationDelay, hideOnDesktop/Tablet/Mobile are present with blank/false defaults', () => {
-    const props = (TextBlock as any).craft.props;
-    expect(props.animation).toBe('');
-    expect(props.animationDelay).toBe('0');
-    expect(props.hideOnDesktop).toBe(false);
-    expect(props.hideOnTablet).toBe(false);
-    expect(props.hideOnMobile).toBe(false);
-  });
-
-  test('style carries blank/default box-model + typography-depth keys', () => {
-    const style = (TextBlock as any).craft.props.style;
-    expect(style).toHaveProperty('marginTop');
-    expect(style).toHaveProperty('paddingTop');
-    expect(style).toHaveProperty('letterSpacing');
-    expect(style).toHaveProperty('textTransform');
-    expect(style.border).toBe('none');
-    expect(style.boxShadow).toBe('none');
-    expect(style.opacity).toBe('1');
-  });
-});
@@ -83,21 +83,7 @@ TextBlock.craft = {
      fontSize: '16px',
      lineHeight: '1.6',
      color: '#3f3f46',
-      letterSpacing: '',
-      textTransform: '' as CSSProperties['textTransform'],
-      fontStyle: '' as CSSProperties['fontStyle'],
-      textDecoration: '',
-      marginTop: '', marginRight: '', marginBottom: '', marginLeft: '',
-      paddingTop: '', paddingRight: '', paddingBottom: '', paddingLeft: '',
-      border: 'none',
-      boxShadow: 'none',
-      opacity: '1',
    },
-    animation: '',
-    animationDelay: '0',
-    hideOnDesktop: false,
-    hideOnTablet: false,
-    hideOnMobile: false,
  },
  rules: {
    canDrag: () => true,
@@ -4,7 +4,6 @@ import {
  BG_COLORS,
  RADIUS_PRESETS,
  SPACING_PRESETS,
-  SHADOW_PRESETS,
 } from '../../../constants/presets';
 import {
  StylePanelProps,
@@ -12,49 +11,16 @@ import {
  ColorSwatchGrid,
  PresetButtonGrid,
  TextInputField,
-  ColorPickerField,
-  CollapsibleSection,
-  SpacingControl,
-  SpacingSide,
-  BorderControl,
-  BorderValue,
-  buildBorderShorthand,
-  AnimationControl,
-  VisibilityControl,
-  sectionGap,
-  labelStyle,
  autoTextColor,
  useNodeProp,
 } from './shared';

-function capitalize(s: string): string {
-  return s.charAt(0).toUpperCase() + s.slice(1);
-}
-
-/** Parses a `border` shorthand string (e.g. "2px solid #ff0000") back into
- *  the {width,style,color} shape BorderControl edits. Only needs to
- *  round-trip values this same panel produced via buildBorderShorthand. */
-function parseBorderShorthand(v: string | undefined): BorderValue {
-  if (!v || v === 'none') return { width: '', style: 'none', color: '#000000' };
-  const m = String(v).trim().match(/^(\d+(?:\.\d+)?(?:px|em|rem)?)\s+(\w+)\s+(.+)$/);
-  if (!m) return { width: '', style: 'none', color: '#000000' };
-  return { width: m[1], style: m[2], color: m[3] };
-}
-
-/** style.opacity is a CSS-length-free numeric string ("0.8") or blank
- *  (treated as fully opaque). Converts to a 0-100 integer for the UI. */
-function opacityPercent(v: unknown): number {
-  if (v === undefined || v === null || v === '') return 100;
-  const n = parseFloat(String(v));
-  return Number.isFinite(n) ? Math.round(n * 100) : 100;
-}
-
 /* ---------- BUTTON ---------- */
 export const ButtonStylePanel: React.FC<StylePanelProps> = ({ selectedId, nodeProps }) => {
  const { actions } = useEditor();
  const style: CSSProperties = nodeProps.style || {};

-  const { setProp, setPropStyle } = useNodeProp(selectedId);
+  const { setPropStyle } = useNodeProp(selectedId);

  const setButtonColor = useCallback(
    (bgColor: string) => {
@@ -95,16 +61,6 @@ export const ButtonStylePanel: React.FC<StylePanelProps> = ({ selectedId, nodePr
          actions.setProp(selectedId, (props: any) => { props.href = v; });
        }}
      />
-      <div className="guided-section">
-        <label style={{ display: 'flex', alignItems: 'center', gap: 6, fontSize: 11, color: '#e4e4e7', cursor: 'pointer' }}>
-          <input
-            type="checkbox"
-            checked={nodeProps.target === '_blank'}
-            onChange={(e) => setProp('target', e.target.checked ? '_blank' : '_self')}
-          />
-          Open in new tab
-        </label>
-      </div>
      <div className="guided-section">
        <SectionLabel>Border Radius</SectionLabel>
        <PresetButtonGrid
@@ -121,70 +77,6 @@ export const ButtonStylePanel: React.FC<StylePanelProps> = ({ selectedId, nodePr
          onSelect={(v) => setPropStyle('padding', v)}
        />
      </div>
-
-      {/* Hover state -- rendered into a scoped <style>...:hover{} block by
-          ButtonLink.toHtml (published export only; not shown live in the
-          editor canvas beyond the hover preview ButtonLink itself does). */}
-      <CollapsibleSection title="Hover State" defaultOpen={false}>
-        <ColorPickerField
-          label="Hover Background"
-          value={nodeProps.hoverBg || ''}
-          onChange={(v) => setProp('hoverBg', v)}
-        />
-        <ColorPickerField
-          label="Hover Text Color"
-          value={nodeProps.hoverColor || ''}
-          onChange={(v) => setProp('hoverColor', v)}
-        />
-      </CollapsibleSection>
-
-      {/* Box model + border/effects + animation/visibility rollout */}
-      <CollapsibleSection title="Spacing" defaultOpen={false}>
-        <SpacingControl
-          label="Margin"
-          value={{ top: style.marginTop as string, right: style.marginRight as string, bottom: style.marginBottom as string, left: style.marginLeft as string }}
-          onChange={(side: SpacingSide, v: string) => setPropStyle(`margin${capitalize(side)}`, v)}
-        />
-      </CollapsibleSection>
-      <CollapsibleSection title="Border & Effects" defaultOpen={false}>
-        <BorderControl
-          value={parseBorderShorthand(style.border as string)}
-          onChange={(v) => setPropStyle('border', buildBorderShorthand(v))}
-        />
-        <div className="guided-section">
-          <SectionLabel>Shadow</SectionLabel>
-          <PresetButtonGrid presets={SHADOW_PRESETS} activeValue={style.boxShadow as string} onSelect={(v) => setPropStyle('boxShadow', v)} />
-        </div>
-        <div style={sectionGap}>
-          <label style={labelStyle}>Opacity: {opacityPercent(style.opacity)}%</label>
-          <input
-            type="range"
-            min={0}
-            max={100}
-            value={opacityPercent(style.opacity)}
-            onChange={(e) => setPropStyle('opacity', String(Number(e.target.value) / 100))}
-            style={{ width: '100%' }}
-          />
-        </div>
-      </CollapsibleSection>
-      <CollapsibleSection title="Animation & Visibility" defaultOpen={false}>
-        <AnimationControl
-          value={{ animation: nodeProps.animation || 'none', animationDelay: nodeProps.animationDelay }}
-          onChange={(v) => { setProp('animation', v.animation); setProp('animationDelay', v.animationDelay); }}
-        />
-        <VisibilityControl
-          value={{
-            hideOnDesktop: nodeProps.hideOnDesktop,
-            hideOnTablet: nodeProps.hideOnTablet,
-            hideOnMobile: nodeProps.hideOnMobile,
-          }}
-          onChange={(v) => {
-            setProp('hideOnDesktop', !!v.hideOnDesktop);
-            setProp('hideOnTablet', !!v.hideOnTablet);
-            setProp('hideOnMobile', !!v.hideOnMobile);
-          }}
-        />
-      </CollapsibleSection>
    </>
  );
 };
@@ -1,4 +1,4 @@
-import React from 'react';
+import React, { useState } from 'react';
 import {
  TEXT_COLORS,
  BG_COLORS,
@@ -17,12 +17,85 @@ import {
  useNodeProp,
 } from './shared';
 import { ArrayItemFieldsEditor } from './ArrayItemFields';
+import { Modal } from '../../../ui/Modal';
+import { CodeEditor } from '../../../ui/CodeEditor';
+
+/* ---------- "Edit HTML" modal for the HtmlBlock `code` prop ----------
+   `code` is raw HTML (potentially many lines, embedded <style>/<script>),
+   so it gets a dedicated syntax-highlighted CodeEditor in a modal instead
+   of falling into the generic single-line/textarea string-prop rendering
+   below (see GenericPropsEditor's SKIP of the `code` key). */
+const HtmlCodeField: React.FC<{ value: string; onChange: (v: string) => void }> = ({ value, onChange }) => {
+  const [open, setOpen] = useState(false);
+  return (
+    <CollapsibleSection title="HTML Code">
+      <div style={sectionGap}>
+        <button
+          onClick={() => setOpen(true)}
+          style={{
+            width: '100%', padding: '8px 12px', fontSize: 12, fontWeight: 600,
+            display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 6,
+            background: '#27272a', color: '#e4e4e7', border: '1px solid #3f3f46',
+            borderRadius: 6, cursor: 'pointer',
+          }}
+        >
+          <i className="fa fa-code" /> Edit HTML
+        </button>
+      </div>
+      <Modal open={open} onClose={() => setOpen(false)} width="min(720px, 90vw)">
+        <div
+          style={{
+            background: 'var(--color-bg-surface)',
+            border: '1px solid var(--color-border)',
+            borderRadius: 12,
+            boxShadow: '0 20px 60px rgba(0,0,0,0.5)',
+            display: 'flex',
+            flexDirection: 'column',
+            overflow: 'hidden',
+          }}
+          onClick={(e) => e.stopPropagation()}
+        >
+          <div style={{
+            display: 'flex', alignItems: 'center', justifyContent: 'space-between',
+            padding: '14px 16px', borderBottom: '1px solid var(--color-border)',
+          }}>
+            <div style={{ fontSize: 14, fontWeight: 600, color: 'var(--color-text)' }}>Edit HTML</div>
+            <button
+              onClick={() => setOpen(false)}
+              style={{
+                width: 28, height: 28, display: 'inline-flex', alignItems: 'center', justifyContent: 'center',
+                background: 'none', border: '1px solid var(--color-border)', borderRadius: 6,
+                color: 'var(--color-text-muted)', cursor: 'pointer', fontSize: 13,
+              }}
+            >
+              <i className="fa fa-times" />
+            </button>
+          </div>
+          <div style={{ padding: 16 }}>
+            <CodeEditor value={value} onChange={onChange} language="html" height={420} />
+          </div>
+          <div style={{ padding: '10px 16px', borderTop: '1px solid var(--color-border)', display: 'flex', justifyContent: 'flex-end' }}>
+            <button
+              onClick={() => setOpen(false)}
+              style={{
+                padding: '7px 20px', fontSize: 13, fontWeight: 600,
+                background: 'var(--color-accent)', color: '#fff', border: 'none', borderRadius: 6, cursor: 'pointer',
+              }}
+            >
+              Done
+            </button>
+          </div>
+        </div>
+      </Modal>
+    </CollapsibleSection>
+  );
+};

 /* ---------- SMART GENERIC PROPS EDITOR (Fallback) ---------- */
 export const GenericPropsEditor: React.FC<{ selectedId: string; nodeProps: Record<string, any>; typeName: string }> = ({
  selectedId, nodeProps, typeName,
 }) => {
-  const SKIP_PROPS = new Set(['style', 'children', 'cssId', 'cssClass']);
+  const SKIP_PROPS = new Set(['style', 'children', 'cssId', 'cssClass', 'code']);

  const { setProp: setPropValue, setPropStyle: setStyleValue } = useNodeProp(selectedId);

@@ -35,9 +108,15 @@ export const GenericPropsEditor: React.FC<{ selectedId: string; nodeProps: Recor
  const arrayProps = allProps.filter(([_, val]) => Array.isArray(val));

  const style = nodeProps.style || {};
+  const hasCodeProp = typeof nodeProps.code === 'string';

  return (
    <>
+      {/* Raw HTML (HtmlBlock's `code` prop) -- dedicated CodeEditor modal */}
+      {hasCodeProp && (
+        <HtmlCodeField value={nodeProps.code} onChange={(v) => setPropValue('code', v)} />
+      )}
+
      {/* String props */}
      {stringProps.length > 0 && (
        <CollapsibleSection title="Properties">
@@ -4,69 +4,20 @@ import {
  FONT_FAMILIES,
  TEXT_SIZES,
  FONT_WEIGHTS,
-  LINE_HEIGHTS,
-  LETTER_SPACINGS,
-  SHADOW_PRESETS,
 } from '../../../constants/presets';
 import {
  StylePanelProps,
  SectionLabel,
  ColorSwatchGrid,
  PresetButtonGrid,
-  NumericUnitInput,
-  CollapsibleSection,
-  SpacingControl,
-  SpacingSide,
-  BorderControl,
-  BorderValue,
-  buildBorderShorthand,
-  AnimationControl,
-  VisibilityControl,
-  sectionGap,
-  labelStyle,
  useNodeProp,
 } from './shared';

-/* Text-transform is a small fixed enum with no natural home in the shared
-   foundation presets (constants/presets.ts is import-only for this
-   package), so it lives here as a package-local preset list. */
-const TEXT_TRANSFORMS: { label: string; value: string }[] = [
-  { label: 'None', value: 'none' },
-  { label: 'UPPER', value: 'uppercase' },
-  { label: 'lower', value: 'lowercase' },
-  { label: 'Capitalize', value: 'capitalize' },
-];
-
-function capitalize(s: string): string {
-  return s.charAt(0).toUpperCase() + s.slice(1);
-}
-
-/** Parses a `border` shorthand string (e.g. "2px solid #ff0000") back into
- *  the {width,style,color} shape BorderControl edits. Only needs to
- *  round-trip values this same panel produced via buildBorderShorthand. */
-function parseBorderShorthand(v: string | undefined): BorderValue {
-  if (!v || v === 'none') return { width: '', style: 'none', color: '#000000' };
-  const m = String(v).trim().match(/^(\d+(?:\.\d+)?(?:px|em|rem)?)\s+(\w+)\s+(.+)$/);
-  if (!m) return { width: '', style: 'none', color: '#000000' };
-  return { width: m[1], style: m[2], color: m[3] };
-}
-
-/** style.opacity is a CSS-length-free numeric string ("0.8") or blank
- *  (treated as fully opaque). Converts to a 0-100 integer for the UI. */
-function opacityPercent(v: unknown): number {
-  if (v === undefined || v === null || v === '') return 100;
-  const n = parseFloat(String(v));
-  return Number.isFinite(n) ? Math.round(n * 100) : 100;
-}
-
 /* ---------- TEXT ---------- */
 export const TextStylePanel: React.FC<StylePanelProps> = ({ selectedId, nodeProps }) => {
  const style: CSSProperties = nodeProps.style || {};

-  const { setProp, setPropStyle } = useNodeProp(selectedId);
-
-  const isItalic = style.fontStyle === 'italic';
-  const isUnderline = style.textDecoration === 'underline';
+  const { setPropStyle } = useNodeProp(selectedId);

  return (
    <>
@@ -93,15 +44,6 @@ export const TextStylePanel: React.FC<StylePanelProps> = ({ selectedId, nodeProp
          activeValue={style.fontSize as string}
          onSelect={(v) => setPropStyle('fontSize', v)}
        />
-        <div style={{ marginTop: 6 }}>
-          <NumericUnitInput
-            value={TEXT_SIZES.some((p) => p.value === style.fontSize) ? '' : ((style.fontSize as string) || '')}
-            onChange={(v) => setPropStyle('fontSize', v)}
-            units={['px', 'em', 'rem', '%']}
-            placeholder="custom"
-            testId="text-fontsize-custom"
-          />
-        </div>
      </div>
      <div className="guided-section">
        <SectionLabel>Font Weight</SectionLabel>
@@ -111,53 +53,6 @@ export const TextStylePanel: React.FC<StylePanelProps> = ({ selectedId, nodeProp
          onSelect={(v) => setPropStyle('fontWeight', v)}
        />
      </div>
-      <div className="guided-section">
-        <SectionLabel>Style</SectionLabel>
-        <div style={{ display: 'flex', gap: 6 }}>
-          <button
-            type="button"
-            className={`preset-btn ${isItalic ? 'active' : ''}`}
-            style={{ flex: 1, fontStyle: 'italic' }}
-            onClick={() => setPropStyle('fontStyle', isItalic ? 'normal' : 'italic')}
-            title="Italic"
-          >
-            <i className="fa fa-italic" /> Italic
-          </button>
-          <button
-            type="button"
-            className={`preset-btn ${isUnderline ? 'active' : ''}`}
-            style={{ flex: 1, textDecoration: 'underline' }}
-            onClick={() => setPropStyle('textDecoration', isUnderline ? 'none' : 'underline')}
-            title="Underline"
-          >
-            <i className="fa fa-underline" /> Underline
-          </button>
-        </div>
-      </div>
-      <div className="guided-section">
-        <SectionLabel>Text Transform</SectionLabel>
-        <PresetButtonGrid
-          presets={TEXT_TRANSFORMS}
-          activeValue={(style.textTransform as string) || 'none'}
-          onSelect={(v) => setPropStyle('textTransform', v === 'none' ? '' : v)}
-        />
-      </div>
-      <div className="guided-section">
-        <SectionLabel>Line Height</SectionLabel>
-        <PresetButtonGrid
-          presets={LINE_HEIGHTS}
-          activeValue={String(style.lineHeight || '')}
-          onSelect={(v) => setPropStyle('lineHeight', v)}
-        />
-      </div>
-      <div className="guided-section">
-        <SectionLabel>Letter Spacing</SectionLabel>
-        <PresetButtonGrid
-          presets={LETTER_SPACINGS}
-          activeValue={String(style.letterSpacing || '')}
-          onSelect={(v) => setPropStyle('letterSpacing', v)}
-        />
-      </div>
      <div className="guided-section">
        <SectionLabel>Alignment</SectionLabel>
        <div className="preset-grid align-grid">
@@ -173,59 +68,6 @@ export const TextStylePanel: React.FC<StylePanelProps> = ({ selectedId, nodeProp
          ))}
        </div>
      </div>
-
-      {/* Box model + border/effects + animation/visibility rollout */}
-      <CollapsibleSection title="Spacing" defaultOpen={false}>
-        <SpacingControl
-          label="Margin"
-          value={{ top: style.marginTop as string, right: style.marginRight as string, bottom: style.marginBottom as string, left: style.marginLeft as string }}
-          onChange={(side: SpacingSide, v: string) => setPropStyle(`margin${capitalize(side)}`, v)}
-        />
-        <SpacingControl
-          label="Padding"
-          value={{ top: style.paddingTop as string, right: style.paddingRight as string, bottom: style.paddingBottom as string, left: style.paddingLeft as string }}
-          onChange={(side: SpacingSide, v: string) => setPropStyle(`padding${capitalize(side)}`, v)}
-        />
-      </CollapsibleSection>
-      <CollapsibleSection title="Border & Effects" defaultOpen={false}>
-        <BorderControl
-          value={parseBorderShorthand(style.border as string)}
-          onChange={(v) => setPropStyle('border', buildBorderShorthand(v))}
-        />
-        <div className="guided-section">
-          <SectionLabel>Shadow</SectionLabel>
-          <PresetButtonGrid presets={SHADOW_PRESETS} activeValue={style.boxShadow as string} onSelect={(v) => setPropStyle('boxShadow', v)} />
-        </div>
-        <div style={sectionGap}>
-          <label style={labelStyle}>Opacity: {opacityPercent(style.opacity)}%</label>
-          <input
-            type="range"
-            min={0}
-            max={100}
-            value={opacityPercent(style.opacity)}
-            onChange={(e) => setPropStyle('opacity', String(Number(e.target.value) / 100))}
-            style={{ width: '100%' }}
-          />
-        </div>
-      </CollapsibleSection>
-      <CollapsibleSection title="Animation & Visibility" defaultOpen={false}>
-        <AnimationControl
-          value={{ animation: nodeProps.animation || 'none', animationDelay: nodeProps.animationDelay }}
-          onChange={(v) => { setProp('animation', v.animation); setProp('animationDelay', v.animationDelay); }}
-        />
-        <VisibilityControl
-          value={{
-            hideOnDesktop: nodeProps.hideOnDesktop,
-            hideOnTablet: nodeProps.hideOnTablet,
-            hideOnMobile: nodeProps.hideOnMobile,
-          }}
-          onChange={(v) => {
-            setProp('hideOnDesktop', !!v.hideOnDesktop);
-            setProp('hideOnTablet', !!v.hideOnTablet);
-            setProp('hideOnMobile', !!v.hideOnMobile);
-          }}
-        />
-      </CollapsibleSection>
    </>
  );
 };
@@ -0,0 +1,85 @@
+import { describe, test, expect, vi, afterEach } from 'vitest';
+import React from 'react';
+import { createRoot, Root } from 'react-dom/client';
+import { act } from 'react-dom/test-utils';
+import { HeadCodeModal } from './HeadCodeModal';
+import { SiteDesignProvider, useSiteDesign } from '../../state/SiteDesignContext';
+
+/* ---------- DOM test harness -- same react-dom/client + `act` pattern used
+   throughout src/ui/*.test.tsx (no @testing-library/react in this repo). ---------- */
+let container: HTMLDivElement;
+let root: Root;
+
+function render(ui: React.ReactElement) {
+  container = document.createElement('div');
+  document.body.appendChild(container);
+  act(() => {
+    root = createRoot(container);
+    root.render(ui);
+  });
+}
+
+afterEach(() => {
+  if (container) {
+    act(() => { root.unmount(); });
+    container.remove();
+  }
+  document.body.style.overflow = '';
+});
+
+// Exposes the current headCode so assertions can read it back after a
+// simulated edit -- CodeEditor writes through `updateDesign`, this just
+// surfaces the result.
+function Harness({ onReady }: { onReady: (headCode: string) => void }) {
+  const { design } = useSiteDesign();
+  onReady(design.headCode);
+  return null;
+}
+
+describe('HeadCodeModal', () => {
+  // HeadCodeModal portals its content to document.body (see the comment in
+  // HeadCodeModal.tsx), so the rendered DOM lives outside `container` --
+  // query document.body instead.
+
+  test('renders the CodeEditor (fallback textarea path) seeded with the current headCode', () => {
+    render(
+      <SiteDesignProvider>
+        <HeadCodeModal open onClose={vi.fn()} />
+      </SiteDesignProvider>,
+    );
+    // CodeMirror loads via async dynamic import (see CodeEditor.test.tsx);
+    // synchronously after mount the fallback textarea is what's live.
+    const textarea = document.body.querySelector<HTMLTextAreaElement>('[data-testid="code-editor-fallback"]');
+    expect(textarea).not.toBeNull();
+    expect(textarea!.value).toBe('');
+    expect(textarea!.dataset.language).toBe('html');
+  });
+
+  test('typing in the editor writes through to SiteDesignContext.headCode', () => {
+    let latestHeadCode = '';
+    render(
+      <SiteDesignProvider>
+        <HeadCodeModal open onClose={vi.fn()} />
+        <Harness onReady={(v) => { latestHeadCode = v; }} />
+      </SiteDesignProvider>,
+    );
+
+    const textarea = document.body.querySelector<HTMLTextAreaElement>('[data-testid="code-editor-fallback"]')!;
+    act(() => {
+      const setter = Object.getOwnPropertyDescriptor(window.HTMLTextAreaElement.prototype, 'value')!.set!;
+      setter.call(textarea, '<meta name="x" content="y">');
+      textarea.dispatchEvent(new Event('input', { bubbles: true }));
+    });
+
+    expect(latestHeadCode).toBe('<meta name="x" content="y">');
+  });
+
+  test('does not render when closed', () => {
+    render(
+      <SiteDesignProvider>
+        <HeadCodeModal open={false} onClose={vi.fn()} />
+      </SiteDesignProvider>,
+    );
+    expect(document.body.querySelector('[data-testid="code-editor-fallback"]')).toBeNull();
+  });
+});
@@ -2,6 +2,7 @@ import React from 'react';
 import { createPortal } from 'react-dom';
 import { useSiteDesign } from '../../state/SiteDesignContext';
 import { Modal } from '../../ui/Modal';
+import { CodeEditor } from '../../ui/CodeEditor';

 interface HeadCodeModalProps {
  open: boolean;
@@ -55,28 +56,16 @@ export const HeadCodeModal: React.FC<HeadCodeModalProps> = ({ open, onClose }) =
            Code added here will be injected into the <code style={{ background: 'rgba(255,255,255,0.08)', padding: '1px 4px', borderRadius: 3, fontSize: 11 }}>&lt;head&gt;</code> of every page on your site. Use it for analytics, custom fonts, or global CSS.
          </div>

-          <textarea
+          <div style={{ flex: 1, minHeight: 300 }}>
+            <CodeEditor
              value={design.headCode || ''}
-            onChange={(e) => updateDesign({ headCode: e.target.value })}
+              onChange={(code) => updateDesign({ headCode: code })}
+              language="html"
+              height="100%"
              placeholder={"<!-- Google Analytics -->\n<script async src=\"https://...\"></script>\n\n<!-- Custom Fonts -->\n<link href=\"https://fonts.googleapis.com/...\" rel=\"stylesheet\">\n\n<style>\n  /* Global CSS overrides */\n  body { }\n</style>"}
-            style={{
-              flex: 1,
-              minHeight: 300,
-              padding: 14,
-              background: '#0d0d0f',
-              color: '#e4e4e7',
-              border: '1px solid #3f3f46',
-              borderRadius: 8,
-              fontFamily: 'Source Code Pro, Consolas, monospace',
-              fontSize: 13,
-              lineHeight: 1.6,
-              resize: 'vertical',
-              outline: 'none',
-              tabSize: 2,
-            }}
-            spellCheck={false}
            />
          </div>
+        </div>

        {/* Footer */}
        <div style={{
@@ -0,0 +1,90 @@
+import { describe, test, expect, vi, afterEach } from 'vitest';
+import React from 'react';
+import { createRoot, Root } from 'react-dom/client';
+import { act } from 'react-dom/test-utils';
+import { CodeEditor } from './CodeEditor';
+
+/* ---------- DOM test harness (no @testing-library/react in this repo; see
+   src/ui/AssetPicker.test.tsx / src/ui/Modal.test.tsx for the same
+   react-dom/client + react-dom/test-utils `act` pattern). ----------
+
+   CodeMirror is loaded via dynamic import() (see CodeEditor.tsx), which is
+   always async -- even for an already-resolved/cached module, `import()`
+   only settles on a later microtask. That means immediately after the
+   initial synchronous `act(() => root.render(...))` below, the component is
+   still in its 'loading' state and renders the <textarea> fallback. These
+   tests deliberately assert against that first-tick DOM (never awaiting
+   the CodeMirror promise), so they exercise exactly the fallback path a
+   real headless/offline environment would fall back to, deterministically
+   and without needing to mock @codemirror/*. */
+
+let container: HTMLDivElement;
+let root: Root;
+
+function render(ui: React.ReactElement) {
+  container = document.createElement('div');
+  document.body.appendChild(container);
+  act(() => {
+    root = createRoot(container);
+    root.render(ui);
+  });
+}
+
+afterEach(() => {
+  if (container) {
+    act(() => { root.unmount(); });
+    container.remove();
+  }
+});
+
+function fallbackTextarea(): HTMLTextAreaElement {
+  const el = container.querySelector<HTMLTextAreaElement>('[data-testid="code-editor-fallback"]');
+  if (!el) throw new Error('fallback textarea not found');
+  return el;
+}
+
+describe('CodeEditor', () => {
+  test('shows the textarea fallback immediately (CodeMirror loads async)', () => {
+    render(<CodeEditor value="<p>hi</p>" onChange={vi.fn()} />);
+    const textarea = fallbackTextarea();
+    expect(textarea.value).toBe('<p>hi</p>');
+  });
+
+  test('the CodeMirror mount root is hidden while the fallback is showing', () => {
+    render(<CodeEditor value="" onChange={vi.fn()} />);
+    const cmRoot = container.querySelector<HTMLDivElement>('[data-testid="code-editor-cm-root"]');
+    expect(cmRoot?.style.display).toBe('none');
+  });
+
+  test('onChange fires with the new value when typing in the fallback textarea', () => {
+    const onChange = vi.fn();
+    render(<CodeEditor value="<p>hi</p>" onChange={onChange} />);
+    const textarea = fallbackTextarea();
+    act(() => {
+      const setter = Object.getOwnPropertyDescriptor(window.HTMLTextAreaElement.prototype, 'value')!.set!;
+      setter.call(textarea, '<p>updated</p>');
+      textarea.dispatchEvent(new Event('input', { bubbles: true }));
+    });
+    expect(onChange).toHaveBeenCalledWith('<p>updated</p>');
+  });
+
+  test('accepts a language prop without throwing (html/css/javascript/auto)', () => {
+    for (const language of ['html', 'css', 'javascript', 'auto'] as const) {
+      expect(() => render(<CodeEditor value="" onChange={vi.fn()} language={language} />)).not.toThrow();
+      const textarea = fallbackTextarea();
+      expect(textarea.dataset.language).toBe(language);
+      act(() => { root.unmount(); });
+      container.remove();
+    }
+  });
+
+  test('defaults to html language when none is passed', () => {
+    render(<CodeEditor value="" onChange={vi.fn()} />);
+    expect(fallbackTextarea().dataset.language).toBe('html');
+  });
+
+  test('respects a custom height', () => {
+    render(<CodeEditor value="" onChange={vi.fn()} height={480} />);
+    expect((container.firstElementChild as HTMLElement).style.height).toBe('480px');
+  });
+});
@@ -0,0 +1,257 @@
+import React, { useEffect, useRef, useState } from 'react';
+import type { EditorView as EditorViewType } from '@codemirror/view';
+
+export type CodeEditorLanguage = 'html' | 'css' | 'javascript' | 'auto';
+
+export interface CodeEditorProps {
+  value: string;
+  onChange: (value: string) => void;
+  /** 'auto' behaves like 'html' -- the HTML language mode already highlights
+   *  embedded <script>/<style> blocks, which covers the common "auto" case
+   *  of mixed markup. */
+  language?: CodeEditorLanguage;
+  height?: number | string;
+  placeholder?: string;
+}
+
+/* ----------------------------------------------------------------
+   Lazy-loaded CodeMirror 6.
+
+   All @codemirror/* packages are pulled in via dynamic import() so they
+   land in their own chunk(s) (see vite.config.ts chunkFileNames) instead of
+   bloating the main editor.js bundle -- most sessions never open a code
+   editor. The module set is fetched once (module-level promise, shared
+   across every CodeEditor instance on the page) and cached forever.
+
+   While the import is in flight -- or if it ever fails (offline, CDN
+   hiccup, an environment where CodeMirror can't mount e.g. some headless
+   test runners) -- callers get a plain <textarea> so editing never breaks,
+   just loses syntax highlighting/autocomplete.
+   ---------------------------------------------------------------- */
+
+interface CmModules {
+  EditorState: typeof import('@codemirror/state').EditorState;
+  EditorView: typeof import('@codemirror/view').EditorView;
+  keymap: typeof import('@codemirror/view').keymap;
+  lineNumbers: typeof import('@codemirror/view').lineNumbers;
+  highlightActiveLine: typeof import('@codemirror/view').highlightActiveLine;
+  highlightActiveLineGutter: typeof import('@codemirror/view').highlightActiveLineGutter;
+  drawSelection: typeof import('@codemirror/view').drawSelection;
+  defaultKeymap: typeof import('@codemirror/commands').defaultKeymap;
+  history: typeof import('@codemirror/commands').history;
+  historyKeymap: typeof import('@codemirror/commands').historyKeymap;
+  indentWithTab: typeof import('@codemirror/commands').indentWithTab;
+  syntaxHighlighting: typeof import('@codemirror/language').syntaxHighlighting;
+  defaultHighlightStyle: typeof import('@codemirror/language').defaultHighlightStyle;
+  bracketMatching: typeof import('@codemirror/language').bracketMatching;
+  indentOnInput: typeof import('@codemirror/language').indentOnInput;
+  foldGutter: typeof import('@codemirror/language').foldGutter;
+  autocompletion: typeof import('@codemirror/autocomplete').autocompletion;
+  completionKeymap: typeof import('@codemirror/autocomplete').completionKeymap;
+  closeBrackets: typeof import('@codemirror/autocomplete').closeBrackets;
+  closeBracketsKeymap: typeof import('@codemirror/autocomplete').closeBracketsKeymap;
+  html: typeof import('@codemirror/lang-html').html;
+  css: typeof import('@codemirror/lang-css').css;
+  javascript: typeof import('@codemirror/lang-javascript').javascript;
+  oneDark: typeof import('@codemirror/theme-one-dark').oneDark;
+}
+
+let cmModulesPromise: Promise<CmModules> | null = null;
+
+function loadCodeMirror(): Promise<CmModules> {
+  if (!cmModulesPromise) {
+    cmModulesPromise = Promise.all([
+      import('@codemirror/state'),
+      import('@codemirror/view'),
+      import('@codemirror/commands'),
+      import('@codemirror/language'),
+      import('@codemirror/autocomplete'),
+      import('@codemirror/lang-html'),
+      import('@codemirror/lang-css'),
+      import('@codemirror/lang-javascript'),
+      import('@codemirror/theme-one-dark'),
+    ]).then(([state, view, commands, language, autocomplete, langHtml, langCss, langJs, theme]) => ({
+      EditorState: state.EditorState,
+      EditorView: view.EditorView,
+      keymap: view.keymap,
+      lineNumbers: view.lineNumbers,
+      highlightActiveLine: view.highlightActiveLine,
+      highlightActiveLineGutter: view.highlightActiveLineGutter,
+      drawSelection: view.drawSelection,
+      defaultKeymap: commands.defaultKeymap,
+      history: commands.history,
+      historyKeymap: commands.historyKeymap,
+      indentWithTab: commands.indentWithTab,
+      syntaxHighlighting: language.syntaxHighlighting,
+      defaultHighlightStyle: language.defaultHighlightStyle,
+      bracketMatching: language.bracketMatching,
+      indentOnInput: language.indentOnInput,
+      foldGutter: language.foldGutter,
+      autocompletion: autocomplete.autocompletion,
+      completionKeymap: autocomplete.completionKeymap,
+      closeBrackets: autocomplete.closeBrackets,
+      closeBracketsKeymap: autocomplete.closeBracketsKeymap,
+      html: langHtml.html,
+      css: langCss.css,
+      javascript: langJs.javascript,
+      oneDark: theme.oneDark,
+    }));
+  }
+  return cmModulesPromise;
+}
+
+function languageExtension(mods: CmModules, language: CodeEditorLanguage) {
+  switch (language) {
+    case 'css':
+      return mods.css();
+    case 'javascript':
+      return mods.javascript();
+    case 'html':
+    case 'auto':
+    default:
+      // lang-html already highlights + completes embedded <script>/<style>
+      // blocks as JS/CSS, which is exactly what "auto" wants for mixed
+      // HTML snippets (head code, HTML blocks).
+      return mods.html({ autoCloseTags: true });
+  }
+}
+
+const fallbackStyle: React.CSSProperties = {
+  width: '100%',
+  height: '100%',
+  padding: 14,
+  background: '#0d0d0f',
+  color: '#e4e4e7',
+  border: '1px solid #3f3f46',
+  borderRadius: 8,
+  fontFamily: 'Source Code Pro, Consolas, monospace',
+  fontSize: 13,
+  lineHeight: 1.6,
+  resize: 'none',
+  outline: 'none',
+  tabSize: 2,
+  boxSizing: 'border-box',
+};
+
+export const CodeEditor: React.FC<CodeEditorProps> = ({
+  value,
+  onChange,
+  language = 'html',
+  height = 320,
+  placeholder,
+}) => {
+  const containerRef = useRef<HTMLDivElement | null>(null);
+  const viewRef = useRef<EditorViewType | null>(null);
+  const onChangeRef = useRef(onChange);
+  onChangeRef.current = onChange;
+  // Tracks the last value this component itself emitted, so the
+  // value-sync effect below doesn't stomp on in-progress typing when the
+  // parent re-renders with the exact same string it was just handed.
+  const lastEmittedRef = useRef(value);
+  const [status, setStatus] = useState<'loading' | 'ready' | 'error'>('loading');
+
+  useEffect(() => {
+    let cancelled = false;
+    setStatus('loading');
+
+    loadCodeMirror()
+      .then((mods) => {
+        if (cancelled || !containerRef.current) return;
+        const updateListener = mods.EditorView.updateListener.of((update) => {
+          if (update.docChanged) {
+            const next = update.state.doc.toString();
+            lastEmittedRef.current = next;
+            onChangeRef.current(next);
+          }
+        });
+        const state = mods.EditorState.create({
+          doc: value,
+          extensions: [
+            mods.lineNumbers(),
+            mods.highlightActiveLineGutter(),
+            mods.highlightActiveLine(),
+            mods.history(),
+            mods.foldGutter(),
+            mods.drawSelection(),
+            mods.indentOnInput(),
+            mods.syntaxHighlighting(mods.defaultHighlightStyle, { fallback: true }),
+            mods.bracketMatching(),
+            mods.closeBrackets(),
+            mods.autocompletion(),
+            mods.keymap.of([
+              ...mods.closeBracketsKeymap,
+              ...mods.historyKeymap,
+              ...mods.completionKeymap,
+              ...mods.defaultKeymap,
+              mods.indentWithTab,
+            ]),
+            languageExtension(mods, language),
+            mods.oneDark,
+            mods.EditorView.lineWrapping,
+            updateListener,
+          ],
+        });
+        const view = new mods.EditorView({ state, parent: containerRef.current });
+        viewRef.current = view;
+        setStatus('ready');
+      })
+      .catch((err) => {
+        // eslint-disable-next-line no-console
+        console.error('CodeEditor: CodeMirror failed to load, falling back to a plain textarea', err);
+        if (!cancelled) setStatus('error');
+      });
+
+    return () => {
+      cancelled = true;
+      viewRef.current?.destroy();
+      viewRef.current = null;
+    };
+    // Re-mount on language change (language is fixed for HTML/CSS/JS
+    // targets in this app -- it never flips on an already-open editor --
+    // but re-creating cleanly if it ever does is simpler/safer than trying
+    // to reconfigure the LanguageSupport extension in place).
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [language]);
+
+  // Keep the live CodeMirror doc in sync if `value` changes from outside
+  // (e.g. the modal is reused for a different field) without clobbering
+  // the cursor position/selection on every keystroke-driven re-render.
+  useEffect(() => {
+    const view = viewRef.current;
+    if (!view || status !== 'ready') return;
+    if (value === lastEmittedRef.current) return;
+    const current = view.state.doc.toString();
+    if (current === value) return;
+    view.dispatch({ changes: { from: 0, to: current.length, insert: value } });
+    lastEmittedRef.current = value;
+  }, [value, status]);
+
+  const showFallback = status !== 'ready';
+
+  return (
+    <div style={{ position: 'relative', height, minHeight: height }}>
+      <div
+        ref={containerRef}
+        data-testid="code-editor-cm-root"
+        style={{
+          height: '100%',
+          overflow: 'auto',
+          borderRadius: 8,
+          border: '1px solid #3f3f46',
+          display: showFallback ? 'none' : 'block',
+        }}
+      />
+      {showFallback && (
+        <textarea
+          data-testid="code-editor-fallback"
+          data-language={language}
+          value={value}
+          onChange={(e) => onChange(e.target.value)}
+          placeholder={status === 'loading' ? (placeholder || 'Loading editor…') : placeholder}
+          spellCheck={false}
+          style={fallbackStyle}
+        />
+      )}
+    </div>
+  );
+};