2026-07-13 14:31:24 +00:00
10 changed files with 852 additions and 64 deletions
@@ -2,7 +2,7 @@
 <html lang="en">
 <head>
  <meta charset="UTF-8" />
-  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover" />
  <title>Site Builder</title>
  <link rel="preconnect" href="https://fonts.googleapis.com">
  <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
@@ -5,6 +5,7 @@ import { usePages } from '../state/PageContext';
 import { DeviceMode } from '../types';
 import { DEVICE_WIDTHS } from '../constants/presets';
 import { exportBodyHtml } from '../utils/html-export';
+import { useIsMobile } from '../hooks/useIsMobile';

 interface CanvasProps {
  device: DeviceMode;
@@ -112,13 +113,18 @@ export const EmptyCanvasHint: React.FC = () => {
      isDragging: state.events.dragged.size > 0,
    };
  });
+  const isMobile = useIsMobile();

  if (!isEmpty || isDragging) return null;

  return (
    <div className="empty-canvas-hint">
      <i className="fa fa-cubes" aria-hidden />
-      <span>Drag blocks from the left panel, or pick a Template to start.</span>
+      <span>
+        {isMobile
+          ? <>Tap <strong>Blocks</strong> below to add content, or pick a Template to start.</>
+          : 'Drag blocks from the left panel, or pick a Template to start.'}
+      </span>
    </div>
  );
 };
@@ -1,12 +1,14 @@
-import React, { useState, useCallback } from 'react';
+import React, { useState, useCallback, useEffect, useRef } from 'react';
 import { useEditor } from '@craftjs/core';
 import { TopBar } from '../panels/topbar/TopBar';
 import { LeftPanel } from '../panels/left/LeftPanel';
 import { RightPanel } from '../panels/right/RightPanel';
+import { MobilePanelBar } from '../panels/mobile/MobilePanelBar';
 import { Canvas } from './Canvas';
 import { ContextMenu } from '../panels/context-menu/ContextMenu';
 import { useContextMenu } from '../hooks/useContextMenu';
 import { useKeyboardShortcuts } from '../hooks/useKeyboardShortcuts';
+import { useIsMobile } from '../hooks/useIsMobile';
 import { DeviceMode } from '../types';

 const SHOW_GUIDES_STORAGE_KEY = 'craft-show-guides';
@@ -21,7 +23,21 @@ function loadShowGuides(): boolean {
 }

 export const EditorShell: React.FC = () => {
+  const isMobile = useIsMobile();
  const [device, setDevice] = useState<DeviceMode>('desktop');
+  // Phase A: default the canvas to the "mobile" preview width the first
+  // time we detect a mobile viewport, so the frame fits without the user
+  // having to reach for the device switcher (now tucked in TopBar's
+  // overflow menu on mobile). Only fires once, and only if the device is
+  // still at its initial default -- it must not fight a device the user
+  // has already picked (e.g. from the overflow menu) on a later re-render.
+  const mobileDeviceAppliedRef = useRef(false);
+  useEffect(() => {
+    if (isMobile && !mobileDeviceAppliedRef.current) {
+      mobileDeviceAppliedRef.current = true;
+      setDevice((current) => (current === 'desktop' ? 'mobile' : current));
+    }
+  }, [isMobile]);
  // Item 10: canvas dashed "guide" outlines toggle -- default ON, persisted
  // so the choice survives a reload. Lifted here (rather than owned by
  // TopBar or Canvas alone) because the toggle button lives in TopBar but
@@ -67,12 +83,13 @@ export const EditorShell: React.FC = () => {
        onToggleGuides={() => setShowGuides(!showGuides)}
      />
      <div className="editor-container">
-        <LeftPanel />
+        {!isMobile && <LeftPanel />}
        <div onContextMenu={handleContextMenu} style={{ flex: 1, display: 'flex', minWidth: 0 }}>
          <Canvas device={device} showGuides={showGuides} />
        </div>
-        <RightPanel />
+        {!isMobile && <RightPanel />}
      </div>
+      {isMobile && <MobilePanelBar />}
      <ContextMenu
        visible={menuState.visible}
        x={menuState.x}
@@ -0,0 +1,72 @@
+import { useEffect, useState } from 'react';
+
+/** Mobile breakpoint for the editor chrome (Phase A). Keep in sync with the
+ *  `@media (max-width: 768px)` block in `src/styles/editor.css` -- both the
+ *  CSS and this hook must agree on where mobile chrome kicks in. */
+export const MOBILE_BREAKPOINT_PX = 768;
+const MOBILE_QUERY = `(max-width: ${MOBILE_BREAKPOINT_PX}px)`;
+
+function computeIsMobile(): boolean {
+  if (typeof window === 'undefined') return false;
+  if (typeof window.matchMedia === 'function') {
+    try {
+      return window.matchMedia(MOBILE_QUERY).matches;
+    } catch {
+      // Fall through to the width check below (e.g. some older/embedded
+      // WebViews expose a matchMedia that throws instead of omitting it).
+    }
+  }
+  return window.innerWidth <= MOBILE_BREAKPOINT_PX;
+}
+
+/**
+ * Reports whether the viewport is at or below the mobile editor breakpoint.
+ * Drives every mobile-only branch introduced in Phase A (bottom tab bar,
+ * collapsed topbar, bottom sheets) -- desktop rendering must stay identical
+ * above the breakpoint, so this is the single source of truth both React
+ * and (via the matching CSS media query) plain CSS use to agree on "mobile".
+ *
+ * Falls back to a `resize` listener + `window.innerWidth` when
+ * `matchMedia` isn't available (e.g. some test/JSDOM environments), so the
+ * hook degrades gracefully rather than throwing.
+ */
+export function useIsMobile(): boolean {
+  const [isMobile, setIsMobile] = useState<boolean>(computeIsMobile);
+
+  useEffect(() => {
+    if (typeof window === 'undefined') return;
+
+    if (typeof window.matchMedia === 'function') {
+      let mql: MediaQueryList | null = null;
+      try {
+        mql = window.matchMedia(MOBILE_QUERY);
+      } catch {
+        mql = null;
+      }
+
+      if (mql) {
+        const handleChange = () => setIsMobile(mql!.matches);
+        handleChange();
+
+        if (typeof mql.addEventListener === 'function') {
+          mql.addEventListener('change', handleChange);
+          return () => mql!.removeEventListener('change', handleChange);
+        }
+
+        // Safari < 14 only supports the deprecated addListener/removeListener pair.
+        const legacyMql = mql as MediaQueryList & {
+          addListener?: (listener: () => void) => void;
+          removeListener?: (listener: () => void) => void;
+        };
+        legacyMql.addListener?.(handleChange);
+        return () => legacyMql.removeListener?.(handleChange);
+      }
+    }
+
+    const handleResize = () => setIsMobile(window.innerWidth <= MOBILE_BREAKPOINT_PX);
+    window.addEventListener('resize', handleResize);
+    return () => window.removeEventListener('resize', handleResize);
+  }, []);
+
+  return isMobile;
+}
@@ -0,0 +1,66 @@
+import React, { useEffect } from 'react';
+
+export interface BottomSheetProps {
+  open: boolean;
+  onClose: () => void;
+  title: string;
+  children: React.ReactNode;
+}
+
+/**
+ * Mobile-only bottom sheet (Phase A). Slides up from the bottom of the
+ * viewport to host one of the existing side-panel components
+ * (BlocksPanel/PagesPanel/LayersPanel/AssetsPanel/GuidedStyles) unchanged,
+ * as the mobile replacement for the desktop fixed left/right panel columns.
+ * See `MobilePanelBar`, which owns which sheet (if any) is open.
+ *
+ * Deliberately NOT a generic replacement for `src/ui/Modal.tsx` (centered
+ * dialog chrome) -- this is anchored to the bottom, sized to ~65dvh, and
+ * has its own drag-handle affordance + internally scrollable body, all of
+ * which Modal doesn't need for its centered use cases.
+ */
+export const BottomSheet: React.FC<BottomSheetProps> = ({ open, onClose, title, children }) => {
+  useEffect(() => {
+    if (!open) return;
+    const handleKeyDown = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') onClose();
+    };
+    window.addEventListener('keydown', handleKeyDown);
+
+    const prevOverflow = document.body.style.overflow;
+    document.body.style.overflow = 'hidden';
+    return () => {
+      window.removeEventListener('keydown', handleKeyDown);
+      document.body.style.overflow = prevOverflow;
+    };
+  }, [open, onClose]);
+
+  if (!open) return null;
+
+  return (
+    <div
+      className="mobile-sheet-backdrop"
+      onClick={(e) => {
+        if (e.target === e.currentTarget) onClose();
+      }}
+    >
+      <div className="mobile-sheet" role="dialog" aria-modal="true" aria-label={title}>
+        <div className="mobile-sheet-handle-row">
+          <span className="mobile-sheet-handle" aria-hidden="true" />
+        </div>
+        <div className="mobile-sheet-header">
+          <span className="mobile-sheet-title">{title}</span>
+          <button
+            type="button"
+            className="mobile-sheet-close"
+            onClick={onClose}
+            aria-label={`Close ${title}`}
+          >
+            <i className="fa fa-times" aria-hidden="true" />
+          </button>
+        </div>
+        <div className="mobile-sheet-body">{children}</div>
+      </div>
+    </div>
+  );
+};
@@ -0,0 +1,69 @@
+import React, { useState } from 'react';
+import { BottomSheet } from './BottomSheet';
+import { BlocksPanel } from '../left/BlocksPanel';
+import { PagesPanel } from '../left/PagesPanel';
+import { LayersPanel } from '../left/LayersPanel';
+import { AssetsPanel } from '../left/AssetsPanel';
+import { GuidedStyles } from '../right/GuidedStyles';
+
+type MobileTab = 'blocks' | 'pages' | 'layers' | 'assets' | 'styles';
+
+const TABS: { id: MobileTab; label: string; icon: string }[] = [
+  { id: 'blocks', label: 'Blocks', icon: 'fa-cube' },
+  { id: 'pages', label: 'Pages', icon: 'fa-file-o' },
+  { id: 'layers', label: 'Layers', icon: 'fa-sitemap' },
+  { id: 'assets', label: 'Assets', icon: 'fa-image' },
+  { id: 'styles', label: 'Styles', icon: 'fa-paint-brush' },
+];
+
+/**
+ * Mobile replacement for the desktop LeftPanel/RightPanel column layout
+ * (Phase A). A fixed bottom tab bar (Blocks/Pages/Layers/Assets/Styles)
+ * toggles a single `BottomSheet` at a time, hosting the SAME panel
+ * component the desktop side panels use -- unchanged, so behavior/state
+ * stays identical, only the chrome around it differs. Tapping the active
+ * tab again, tapping the backdrop, the sheet's close button, or Escape all
+ * close the open sheet.
+ *
+ * "Styles" hosts `GuidedStyles`, which already falls back to the
+ * site-design panel when nothing is selected and switches to the
+ * per-type style panel once something is -- this is the natural place to
+ * edit a tapped element's styling (Phase B deepens the tap-to-select flow;
+ * this component only wires up the sheet, per the Phase A brief).
+ */
+export const MobilePanelBar: React.FC = () => {
+  const [activeTab, setActiveTab] = useState<MobileTab | null>(null);
+
+  const handleTabClick = (tab: MobileTab) => {
+    setActiveTab((current) => (current === tab ? null : tab));
+  };
+
+  const activeLabel = TABS.find((t) => t.id === activeTab)?.label ?? '';
+
+  return (
+    <>
+      <BottomSheet open={activeTab !== null} onClose={() => setActiveTab(null)} title={activeLabel}>
+        {activeTab === 'blocks' && <BlocksPanel />}
+        {activeTab === 'pages' && <PagesPanel />}
+        {activeTab === 'layers' && <LayersPanel />}
+        {activeTab === 'assets' && <AssetsPanel />}
+        {activeTab === 'styles' && <GuidedStyles />}
+      </BottomSheet>
+
+      <nav className="mobile-tab-bar" aria-label="Editor panels">
+        {TABS.map((tab) => (
+          <button
+            key={tab.id}
+            type="button"
+            className={`mobile-tab-btn${activeTab === tab.id ? ' active' : ''}`}
+            onClick={() => handleTabClick(tab.id)}
+            aria-pressed={activeTab === tab.id}
+          >
+            <i className={`fa ${tab.icon}`} aria-hidden="true" />
+            <span>{tab.label}</span>
+          </button>
+        ))}
+      </nav>
+    </>
+  );
+};
@@ -253,8 +253,10 @@ export const TemplateModal: React.FC<TemplateModalProps> = ({ open, onClose }) =
          </div>
          <button
            onClick={onClose}
+            className="template-modal-close-btn"
            style={closeButtonStyle}
            title="Close"
+            aria-label="Close"
            onMouseEnter={(e) => { (e.currentTarget as HTMLElement).style.background = 'var(--color-bg-hover)'; (e.currentTarget as HTMLElement).style.color = 'var(--color-text)'; }}
            onMouseLeave={(e) => { (e.currentTarget as HTMLElement).style.background = 'transparent'; (e.currentTarget as HTMLElement).style.color = '#71717a'; }}
          >
@@ -262,11 +264,15 @@ export const TemplateModal: React.FC<TemplateModalProps> = ({ open, onClose }) =
          </button>
        </div>

-        {/* Filter Tabs */}
-        <div style={tabBarStyle}>
+        {/* Filter Tabs -- horizontally scrollable (tabBarStyle sets
+            overflowX: 'auto') so the row never wraps/overflows the modal at
+            narrow widths; template-modal-tab-btn below keeps each tab from
+            shrinking below a comfortable touch target on mobile. */}
+        <div className="template-modal-tabbar" style={tabBarStyle}>
          {TABS.map((tab) => (
            <button
              key={tab.value}
+              className="template-modal-tab-btn"
              onClick={() => setActiveTab(tab.value)}
              style={{
                ...tabStyle,
@@ -4,9 +4,11 @@ import { useEditorConfig } from '../../state/EditorConfigContext';
 import { useWhpApi } from '../../hooks/useWhpApi';
 import { usePages } from '../../state/PageContext';
 import { useSiteDesign } from '../../state/SiteDesignContext';
+import { useIsMobile } from '../../hooks/useIsMobile';
 import { DeviceMode } from '../../types';
 import { TemplateModal } from './TemplateModal';
 import { HeadCodeModal } from './HeadCodeModal';
+import { TopBarOverflowMenu } from './TopBarOverflowMenu';
 import { SitesmithButton } from '../sitesmith/SitesmithButton';
 import { useSitesmithModal } from '../../state/SitesmithContext';

@@ -33,6 +35,8 @@ export const TopBar: React.FC<TopBarProps> = ({ device, onDeviceChange, showGuid
  const [isDraft, setIsDraft] = useState(false);
  const [templateModalOpen, setTemplateModalOpen] = useState(false);
  const [headCodeModalOpen, setHeadCodeModalOpen] = useState(false);
+  const [overflowOpen, setOverflowOpen] = useState(false);
+  const isMobile = useIsMobile();
  const { open: openSitesmith } = useSitesmithModal();
  const saveTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
  const publishTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
@@ -122,6 +126,156 @@ export const TopBar: React.FC<TopBarProps> = ({ device, onDeviceChange, showGuid
    };
  }, []);

+  // Extracted so both the desktop inline Preview button and the mobile
+  // overflow-menu "Preview" item can trigger the exact same flow.
+  const handlePreview = useCallback(() => {
+    try {
+      const serialized = query.serialize();
+      import('../../utils/html-export').then(({ exportToHtml, exportBodyHtml }) => {
+        // Get header HTML
+        let headerHtml = '';
+        try {
+          if (headerPage.craftState) {
+            headerHtml = exportBodyHtml(headerPage.craftState).html;
+          }
+        } catch (e) { console.warn('Header export failed:', e); }
+
+        // Get page body HTML
+        const bodyResult = exportBodyHtml(serialized);
+        const bodyHtml = bodyResult.html;
+
+        // Get footer HTML
+        let footerHtml = '';
+        try {
+          if (footerPage.craftState) {
+            footerHtml = exportBodyHtml(footerPage.craftState).html;
+          }
+        } catch (e) { console.warn('Footer export failed:', e); }
+
+        // Compose full page: header + body + footer
+        const composedBody = headerHtml + bodyHtml + footerHtml;
+        const result = exportToHtml(serialized, {
+          title: whpConfig?.siteName || 'Preview',
+          includeFonts: true,
+          headCode: design.headCode,
+        });
+
+        // Replace the body in the full document with our composed version.
+        // Use a function replacer -- a plain string replacer treats
+        // `$&`/`$1`/`$$` sequences in user content as replacement
+        // patterns, silently corrupting the output.
+        let html = result.html;
+        const bodyMatch = html.match(/<body[^>]*>([\s\S]*)<\/body>/i);
+        if (bodyMatch) {
+          html = html.replace(bodyMatch[1], () => composedBody);
+        }
+
+        // Make proxy URLs absolute so they work from the blob: context
+        const origin = window.location.origin;
+        html = html.replace(/src="\/api\//g, `src="${origin}/api/`);
+        html = html.replace(/url\('\/api\//g, `url('${origin}/api/`);
+        const blob = new Blob([html], { type: 'text/html' });
+        const url = URL.createObjectURL(blob);
+        window.open(url, '_blank');
+      });
+    } catch (e) {
+      console.error('Preview failed:', e);
+    }
+  }, [query, headerPage, footerPage, whpConfig, design]);
+
+  // Phase A: at ≤768px the topbar collapses to only the essentials --
+  // back arrow, Undo/Redo, Save (+Publish) -- with Templates, Sitesmith,
+  // Preview, Head Code, the guides toggle, and the device switcher moved
+  // into the "⋯" overflow menu. This keeps desktop's JSX/behavior below
+  // completely untouched.
+  if (isMobile) {
+    return (
+      <nav className="topbar topbar-mobile">
+        <div className="topbar-left">
+          {isWHP && (
+            <a
+              href={whpConfig!.backUrl}
+              className="topbar-btn icon-only back-btn"
+              aria-label="Back to Panel"
+              data-tooltip="Back"
+            >
+              <i className="fa fa-arrow-left" />
+            </a>
+          )}
+        </div>
+
+        <div className="topbar-right">
+          <button
+            className="topbar-btn icon-only"
+            onClick={() => actions.history.undo()}
+            disabled={!canUndo}
+            aria-label="Undo"
+            data-tooltip="Undo"
+          >
+            <i className="fa fa-undo" />
+          </button>
+          <button
+            className="topbar-btn icon-only"
+            onClick={() => actions.history.redo()}
+            disabled={!canRedo}
+            aria-label="Redo"
+            data-tooltip="Redo"
+          >
+            <i className="fa fa-repeat" />
+          </button>
+          <span className="topbar-divider" />
+          <button
+            className="topbar-btn icon-only primary"
+            onClick={handleSave}
+            disabled={saveStatus === 'saving'}
+            aria-label="Save Draft"
+            data-tooltip="Save"
+          >
+            <i className={`fa ${saveStatus === 'saving' ? 'fa-spinner fa-spin' : 'fa-save'}`} />
+          </button>
+          {isWHP && (
+            <button
+              className="topbar-btn icon-only publish"
+              onClick={handlePublish}
+              disabled={publishStatus === 'publishing' || saveStatus === 'saving'}
+              aria-label="Publish to live site"
+              data-tooltip="Publish"
+            >
+              <i className={`fa ${publishStatus === 'publishing' ? 'fa-spinner fa-spin' : 'fa-globe'}`} />
+            </button>
+          )}
+          <button
+            type="button"
+            className={`topbar-btn icon-only overflow-toggle${overflowOpen ? ' active' : ''}`}
+            onClick={() => setOverflowOpen((v) => !v)}
+            aria-label="More options"
+            aria-expanded={overflowOpen}
+            aria-haspopup="menu"
+            data-tooltip="More"
+          >
+            <i className="fa fa-ellipsis-h" />
+          </button>
+        </div>
+
+        <TopBarOverflowMenu
+          open={overflowOpen}
+          onClose={() => setOverflowOpen(false)}
+          device={device}
+          onDeviceChange={onDeviceChange}
+          showGuides={showGuides}
+          onToggleGuides={onToggleGuides}
+          onOpenTemplates={() => setTemplateModalOpen(true)}
+          onOpenHeadCode={() => setHeadCodeModalOpen(true)}
+          onPreview={handlePreview}
+          sitesmithNode={<SitesmithButton onClick={() => openSitesmith()} />}
+        />
+
+        <TemplateModal open={templateModalOpen} onClose={() => setTemplateModalOpen(false)} />
+        <HeadCodeModal open={headCodeModalOpen} onClose={() => setHeadCodeModalOpen(false)} />
+      </nav>
+    );
+  }
+
  return (
    <nav className="topbar">
      <div className="topbar-left">
@@ -182,60 +336,7 @@ export const TopBar: React.FC<TopBarProps> = ({ device, onDeviceChange, showGuid
        >
          <i className="fa fa-code" />
        </button>
-        <button className="topbar-btn icon-only" aria-label="Preview" data-tooltip="Preview" onClick={() => {
-          try {
-            const serialized = query.serialize();
-            import('../../utils/html-export').then(({ exportToHtml, exportBodyHtml }) => {
-              // Get header HTML
-              let headerHtml = '';
-              try {
-                if (headerPage.craftState) {
-                  headerHtml = exportBodyHtml(headerPage.craftState).html;
-                }
-              } catch (e) { console.warn('Header export failed:', e); }
-
-              // Get page body HTML
-              const bodyResult = exportBodyHtml(serialized);
-              const bodyHtml = bodyResult.html;
-
-              // Get footer HTML
-              let footerHtml = '';
-              try {
-                if (footerPage.craftState) {
-                  footerHtml = exportBodyHtml(footerPage.craftState).html;
-                }
-              } catch (e) { console.warn('Footer export failed:', e); }
-
-              // Compose full page: header + body + footer
-              const composedBody = headerHtml + bodyHtml + footerHtml;
-              const result = exportToHtml(serialized, {
-                title: whpConfig?.siteName || 'Preview',
-                includeFonts: true,
-                headCode: design.headCode,
-              });
-
-              // Replace the body in the full document with our composed version.
-              // Use a function replacer -- a plain string replacer treats
-              // `$&`/`$1`/`$$` sequences in user content as replacement
-              // patterns, silently corrupting the output.
-              let html = result.html;
-              const bodyMatch = html.match(/<body[^>]*>([\s\S]*)<\/body>/i);
-              if (bodyMatch) {
-                html = html.replace(bodyMatch[1], () => composedBody);
-              }
-
-              // Make proxy URLs absolute so they work from the blob: context
-              const origin = window.location.origin;
-              html = html.replace(/src="\/api\//g, `src="${origin}/api/`);
-              html = html.replace(/url\('\/api\//g, `url('${origin}/api/`);
-              const blob = new Blob([html], { type: 'text/html' });
-              const url = URL.createObjectURL(blob);
-              window.open(url, '_blank');
-            });
-          } catch (e) {
-            console.error('Preview failed:', e);
-          }
-        }}>
+        <button className="topbar-btn icon-only" aria-label="Preview" data-tooltip="Preview" onClick={handlePreview}>
          <i className="fa fa-eye" />
        </button>

@@ -0,0 +1,110 @@
+import React, { useEffect, useRef } from 'react';
+import { DeviceMode } from '../../types';
+
+export interface TopBarOverflowMenuProps {
+  open: boolean;
+  onClose: () => void;
+  device: DeviceMode;
+  onDeviceChange: (device: DeviceMode) => void;
+  showGuides: boolean;
+  onToggleGuides: () => void;
+  onOpenTemplates: () => void;
+  onOpenHeadCode: () => void;
+  onPreview: () => void;
+  /** Rendered `<SitesmithButton onClick={...} />` -- passed in rather than
+   *  re-implemented here so the mobile menu reuses the exact same
+   *  lock/cap-aware button the desktop topbar shows. */
+  sitesmithNode: React.ReactNode;
+}
+
+/**
+ * Mobile topbar "⋯" overflow menu (Phase A). At ≤768px, TopBar collapses to
+ * just the back arrow, Undo/Redo, Save/Publish, and this menu -- everything
+ * else that's inline on desktop (Templates, Sitesmith, Preview, Head Code,
+ * the guides toggle, and the device-width switcher) moves in here so the
+ * collapsed bar never overlaps or pushes controls off-screen.
+ */
+export const TopBarOverflowMenu: React.FC<TopBarOverflowMenuProps> = ({
+  open,
+  onClose,
+  device,
+  onDeviceChange,
+  showGuides,
+  onToggleGuides,
+  onOpenTemplates,
+  onOpenHeadCode,
+  onPreview,
+  sitesmithNode,
+}) => {
+  const menuRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    if (!open) return;
+    const handleClick = (e: MouseEvent) => {
+      if (menuRef.current && !menuRef.current.contains(e.target as Node)) onClose();
+    };
+    const handleEsc = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') onClose();
+    };
+    document.addEventListener('mousedown', handleClick);
+    document.addEventListener('keydown', handleEsc);
+    return () => {
+      document.removeEventListener('mousedown', handleClick);
+      document.removeEventListener('keydown', handleEsc);
+    };
+  }, [open, onClose]);
+
+  if (!open) return null;
+
+  const runAndClose = (fn: () => void) => () => {
+    fn();
+    onClose();
+  };
+
+  return (
+    <div ref={menuRef} className="topbar-overflow-menu" role="menu">
+      <div className="topbar-overflow-section">
+        <span className="topbar-overflow-label">Preview width</span>
+        <div className="device-switcher">
+          {(['desktop', 'tablet', 'mobile'] as DeviceMode[]).map((d) => (
+            <button
+              key={d}
+              type="button"
+              className={`device-btn ${device === d ? 'active' : ''}`}
+              onClick={() => onDeviceChange(d)}
+              title={d.charAt(0).toUpperCase() + d.slice(1)}
+              aria-label={d.charAt(0).toUpperCase() + d.slice(1)}
+              aria-pressed={device === d}
+            >
+              <i className={`fa ${d === 'desktop' ? 'fa-desktop' : d === 'tablet' ? 'fa-tablet' : 'fa-mobile'}`} />
+            </button>
+          ))}
+        </div>
+      </div>
+
+      <button type="button" className="topbar-overflow-item" role="menuitem" onClick={runAndClose(onOpenTemplates)}>
+        <i className="fa fa-th-large" aria-hidden="true" /> Templates
+      </button>
+      <button type="button" className="topbar-overflow-item" role="menuitem" onClick={runAndClose(onPreview)}>
+        <i className="fa fa-eye" aria-hidden="true" /> Preview
+      </button>
+      <button type="button" className="topbar-overflow-item" role="menuitem" onClick={runAndClose(onOpenHeadCode)}>
+        <i className="fa fa-code" aria-hidden="true" /> Head Code
+      </button>
+      <button
+        type="button"
+        className={`topbar-overflow-item${showGuides ? ' active' : ''}`}
+        role="menuitem"
+        onClick={runAndClose(onToggleGuides)}
+        aria-pressed={showGuides}
+      >
+        <i className={`fa ${showGuides ? 'fa-th' : 'fa-th-large'}`} aria-hidden="true" />
+        {' '}{showGuides ? 'Hide Guides' : 'Show Guides'}
+      </button>
+
+      <div className="topbar-overflow-sitesmith" onClick={onClose}>
+        {sitesmithNode}
+      </div>
+    </div>
+  );
+};
@@ -31,6 +31,9 @@
  --radius-lg: 8px;
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
+  /* Phase A (mobile): fixed bottom tab bar height, used to size
+     .editor-container and the safe-area padding math below. */
+  --mobile-tabbar-height: 58px;
 }

 /* --------------------------------------------------------------------------
@@ -1377,13 +1380,351 @@ body {
 }

@media (max-width: 768px) {
+  /* ------------------------------------------------------------------------
+     Phase A -- Mobile Editor Chrome
+     Gated entirely behind this breakpoint; desktop styles above are
+     untouched. See useIsMobile() (same 768px breakpoint) for the React-side
+     equivalent that swaps LeftPanel/RightPanel for MobilePanelBar, and
+     collapses TopBar.
+     ------------------------------------------------------------------------ */
+
+  /* Side panels are not rendered on mobile (EditorShell swaps them for the
+     bottom tab bar) -- kept as a defensive fallback in case either is ever
+     mounted at this width. */
  .panel-left,
  .panel-right {
    display: none;
  }

-  .topbar-btn span,
-  .topbar-domain {
-    display: none;
+  /* --------------------------------------------------------------------
+     Viewport sizing -- dynamic viewport height accounts for mobile
+     browsers' collapsing URL bar; the unconditional 100vh set earlier in
+     this file is the fallback for browsers without dvh support.
+     -------------------------------------------------------------------- */
+  .editor-app {
+    height: 100vh;
+    height: 100dvh;
+    padding-top: env(safe-area-inset-top, 0px);
+    padding-left: env(safe-area-inset-left, 0px);
+    padding-right: env(safe-area-inset-right, 0px);
+  }
+
+  .editor-container {
+    height: calc(100vh - var(--topbar-height) - var(--mobile-tabbar-height) - env(safe-area-inset-bottom, 0px));
+    height: calc(100dvh - var(--topbar-height) - var(--mobile-tabbar-height) - env(safe-area-inset-bottom, 0px));
+  }
+
+  /* Full-width canvas, safe-area-aware bottom padding so content never
+     sits flush against the fixed bottom tab bar. */
+  .editor-canvas {
+    padding: 12px;
+  }
+
+  /* --------------------------------------------------------------------
+     Topbar collapse (TopBar.tsx renders a distinct `.topbar-mobile` markup
+     branch -- this is purely the styling for it)
+     -------------------------------------------------------------------- */
+  .topbar-mobile {
+    padding: 0 8px;
+    padding-left: calc(8px + env(safe-area-inset-left, 0px));
+    padding-right: calc(8px + env(safe-area-inset-right, 0px));
+    gap: 4px;
+  }
+
+  .topbar-mobile .topbar-left {
+    flex: 0 0 auto;
+  }
+
+  .topbar-mobile .topbar-right {
+    flex: 1;
+    justify-content: flex-end;
+    gap: 4px;
+  }
+
+  .topbar-mobile .topbar-btn.icon-only {
+    width: 44px;
+    height: 44px;
+    padding: 0;
+    justify-content: center;
+    touch-action: manipulation;
+  }
+
+  .topbar-mobile .topbar-divider {
+    margin: 0 2px;
+  }
+
+  .topbar-btn.overflow-toggle.active {
+    color: var(--color-accent);
+    background: var(--color-accent-subtle);
+    border-color: var(--color-accent);
+  }
+
+  /* --------------------------------------------------------------------
+     "⋯" overflow menu (TopBarOverflowMenu.tsx)
+     -------------------------------------------------------------------- */
+  .topbar-overflow-menu {
+    position: fixed;
+    top: calc(var(--topbar-height) + env(safe-area-inset-top, 0px) + 6px);
+    right: calc(8px + env(safe-area-inset-right, 0px));
+    z-index: 10000;
+    min-width: 220px;
+    max-width: calc(100vw - 16px);
+    max-height: calc(100dvh - var(--topbar-height) - 24px);
+    overflow-y: auto;
+    background: var(--color-bg-elevated);
+    border: 1px solid var(--color-border);
+    border-radius: var(--radius-lg);
+    box-shadow: 0 8px 28px rgba(0, 0, 0, 0.5);
+    padding: 8px;
+    display: flex;
+    flex-direction: column;
+    gap: 4px;
+  }
+
+  .topbar-overflow-section {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 10px;
+    padding: 6px 8px 10px;
+    border-bottom: 1px solid var(--color-border);
+    margin-bottom: 4px;
+  }
+
+  .topbar-overflow-label {
+    font-size: 12px;
+    color: var(--color-text-muted);
+    white-space: nowrap;
+  }
+
+  .topbar-overflow-section .device-switcher {
+    height: 44px;
+  }
+
+  .topbar-overflow-section .device-btn {
+    width: 44px;
+    height: 42px;
+    touch-action: manipulation;
+  }
+
+  .topbar-overflow-item {
+    display: flex;
+    align-items: center;
+    gap: 10px;
+    width: 100%;
+    min-height: 44px;
+    padding: 8px 10px;
+    font-size: 13px;
+    font-weight: 500;
+    color: var(--color-text);
+    background: transparent;
+    border: none;
+    border-radius: var(--radius-md);
+    cursor: pointer;
+    text-align: left;
+    touch-action: manipulation;
+  }
+
+  .topbar-overflow-item:hover,
+  .topbar-overflow-item:active {
+    background: var(--color-bg-hover);
+  }
+
+  .topbar-overflow-item.active {
+    color: var(--color-accent);
+  }
+
+  .topbar-overflow-sitesmith {
+    padding: 6px 4px 0;
+  }
+
+  .topbar-overflow-sitesmith .sitesmith-btn {
+    width: 100%;
+    justify-content: center;
+    min-height: 44px;
+  }
+
+  /* --------------------------------------------------------------------
+     Bottom tab bar (MobilePanelBar.tsx)
+     -------------------------------------------------------------------- */
+  .mobile-tab-bar {
+    position: fixed;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    /* Above .mobile-sheet-backdrop (400) -- the tab bar must stay clickable
+       even while a sheet is open so tapping a different tab swaps sheets
+       directly, instead of requiring a close-then-reopen round trip. The
+       backdrop itself stops short of the tab bar (see its `bottom` offset
+       below) so this is mostly belt-and-suspenders for the boundary. */
+    z-index: 500;
+    display: flex;
+    height: calc(var(--mobile-tabbar-height) + env(safe-area-inset-bottom, 0px));
+    background: var(--color-bg-surface);
+    border-top: 1px solid var(--color-border);
+    padding-bottom: env(safe-area-inset-bottom, 0px);
+    padding-left: env(safe-area-inset-left, 0px);
+    padding-right: env(safe-area-inset-right, 0px);
+  }
+
+  .mobile-tab-btn {
+    flex: 1;
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    gap: 3px;
+    min-height: 44px;
+    font-size: 10px;
+    font-weight: 600;
+    color: var(--color-text-muted);
+    background: transparent;
+    border: none;
+    touch-action: manipulation;
+  }
+
+  .mobile-tab-btn i {
+    font-size: 17px;
+  }
+
+  .mobile-tab-btn.active {
+    color: var(--color-accent);
+  }
+
+  /* --------------------------------------------------------------------
+     Bottom sheet (BottomSheet.tsx)
+     -------------------------------------------------------------------- */
+  .mobile-sheet-backdrop {
+    position: fixed;
+    top: 0;
+    left: 0;
+    right: 0;
+    /* Stop above the bottom tab bar (rather than a full-viewport `inset: 0`)
+       so the tab bar is never covered/blocked by the backdrop -- tapping a
+       different tab while a sheet is open swaps sheets directly instead of
+       being swallowed by the overlay sitting on top of it. */
+    bottom: calc(var(--mobile-tabbar-height) + env(safe-area-inset-bottom, 0px));
+    background: rgba(0, 0, 0, 0.5);
+    z-index: 400;
+    display: flex;
+    align-items: flex-end;
+  }
+
+  .mobile-sheet {
+    width: 100%;
+    max-height: 65vh;
+    max-height: 65dvh;
+    background: var(--color-bg-surface);
+    border-top-left-radius: 16px;
+    border-top-right-radius: 16px;
+    border: 1px solid var(--color-border);
+    border-bottom: none;
+    display: flex;
+    flex-direction: column;
+    overflow: hidden;
+  }
+
+  .mobile-sheet-handle-row {
+    display: flex;
+    justify-content: center;
+    padding: 8px 0 4px;
+    flex-shrink: 0;
+  }
+
+  .mobile-sheet-handle {
+    width: 36px;
+    height: 4px;
+    border-radius: 2px;
+    background: var(--color-border-light);
+  }
+
+  .mobile-sheet-header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    padding: 4px 12px 10px 16px;
+    border-bottom: 1px solid var(--color-border);
+    flex-shrink: 0;
+  }
+
+  .mobile-sheet-title {
+    font-size: 14px;
+    font-weight: 600;
+    color: var(--color-text);
+  }
+
+  .mobile-sheet-close {
+    width: 44px;
+    height: 44px;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    font-size: 16px;
+    color: var(--color-text-muted);
+    background: transparent;
+    border: none;
+    border-radius: var(--radius-md);
+    cursor: pointer;
+    touch-action: manipulation;
+  }
+
+  .mobile-sheet-body {
+    flex: 1;
+    overflow-y: auto;
+    -webkit-overflow-scrolling: touch;
+    padding: 12px 16px;
+  }
+
+  /* --------------------------------------------------------------------
+     Touch ergonomics inside sheets -- 16px inputs kill iOS's auto-zoom on
+     focus; touch-action speeds up tap response on chrome that doesn't need
+     native scroll-gesture handling.
+     -------------------------------------------------------------------- */
+  .mobile-sheet-body button,
+  .mobile-sheet-body .block-item {
+    touch-action: manipulation;
+  }
+
+  .mobile-sheet-body input,
+  .mobile-sheet-body select,
+  .mobile-sheet-body textarea,
+  .guided-input,
+  .control-input,
+  .control-select,
+  .topbar input,
+  .topbar textarea,
+  .topbar select {
+    font-size: 16px;
+  }
+
+  .mobile-sheet-body .settings-tabs button {
+    min-height: 44px;
+  }
+
+  .mobile-sheet-body .color-preset {
+    width: 40px;
+    height: 40px;
+  }
+
+  /* --------------------------------------------------------------------
+     Templates modal: category tabs stay horizontally scrollable and never
+     shrink below a comfortable touch target; close button enlarged to the
+     44px minimum (overriding its 32px inline style).
+     -------------------------------------------------------------------- */
+  .template-modal-tabbar {
+    gap: 8px;
+    -webkit-overflow-scrolling: touch;
+  }
+
+  .template-modal-tab-btn {
+    flex-shrink: 0;
+    min-height: 44px;
+    padding: 8px 16px !important;
+    touch-action: manipulation;
+  }
+
+  .template-modal-close-btn {
+    width: 44px !important;
+    height: 44px !important;
  }
 }