diff --git a/craft/src/components/basic/HtmlBlock.test.ts b/craft/src/components/basic/HtmlBlock.test.ts
index 86fa33d..4b9ebed 100644
--- a/craft/src/components/basic/HtmlBlock.test.ts
+++ b/craft/src/components/basic/HtmlBlock.test.ts
@@ -21,3 +21,46 @@ describe('purifyHtml', () => {
     expect(purifyHtml('<form><input name="x"></form>')).not.toContain('<form');
   });
 });
+
+describe('purifyHtml iframe sandboxing (M-6)', () => {
+  test('forces a restrictive sandbox attribute onto every iframe', () => {
+    const out = purifyHtml('<iframe src="https://example.com/"></iframe>');
+    expect(out).toMatch(/<iframe[^>]*\bsandbox="[^"]+"/);
+  });
+
+  test('sandbox value omits allow-top-navigation (no top-level nav escape)', () => {
+    const out = purifyHtml('<iframe src="https://example.com/"></iframe>');
+    const sandbox = out.match(/sandbox="([^"]*)"/)![1];
+    expect(sandbox).not.toMatch(/allow-top-navigation/);
+  });
+
+  test('legitimate embeds (YouTube) still work and get sandboxed too', () => {
+    const out = purifyHtml('<iframe src="https://www.youtube.com/embed/abc" allowfullscreen></iframe>');
+    expect(out).toContain('youtube.com/embed/abc');
+    expect(out).toMatch(/<iframe[^>]*\bsandbox="[^"]+"/);
+  });
+
+  test('adds referrerpolicy=no-referrer to iframes', () => {
+    const out = purifyHtml('<iframe src="https://example.com/"></iframe>');
+    expect(out).toContain('referrerpolicy="no-referrer"');
+  });
+
+  test('script/on* attributes are still stripped alongside the sandboxed iframe', () => {
+    const out = purifyHtml('<iframe src="https://example.com/" onload="alert(1)"></iframe><script>alert(2)</script>');
+    expect(out).not.toContain('onload');
+    expect(out).not.toContain('<script');
+  });
+
+  test('repeated calls do not leak/accumulate the hook (no duplicate sandbox attr, no cross-call state)', () => {
+    purifyHtml('<iframe src="https://a.example/"></iframe>');
+    purifyHtml('<iframe src="https://b.example/"></iframe>');
+    const out = purifyHtml('<iframe src="https://c.example/"></iframe>');
+    const sandboxMatches = out.match(/sandbox="/g) || [];
+    expect(sandboxMatches.length).toBe(1);
+  });
+
+  test('a non-iframe element sanitized alongside an iframe is not touched by the hook', () => {
+    const out = purifyHtml('<p>hi</p><iframe src="https://example.com/"></iframe>');
+    expect(out).toContain('<p>hi</p>');
+  });
+});
diff --git a/craft/src/components/basic/HtmlBlock.tsx b/craft/src/components/basic/HtmlBlock.tsx
index 4fa7f8a..0f41cc4 100644
--- a/craft/src/components/basic/HtmlBlock.tsx
+++ b/craft/src/components/basic/HtmlBlock.tsx
@@ -24,14 +24,42 @@ const PURIFY_CONFIG = {
     'href','src','alt','title','target','rel',
     'width','height','class',
     'allowfullscreen','allow','frameborder',
+    'sandbox','referrerpolicy',
   ],
   ALLOWED_URI_REGEXP: /^(?:(?:https?|mailto|tel|data:image\/[a-z]+;base64,):|[^a-z]|[a-z+.-]+(?:[^a-z+.\-:]|$))/i,
   FORBID_TAGS: ['script','style','object','embed','link','meta','form','input','button','select','textarea'],
   FORBID_ATTR: [/^on/i],
 };
 
+// M-6: `<iframe>` is allowed (maps/video embeds are a legitimate use case)
+// but an iframe with a `src` and NO `sandbox` attribute is a clickjacking/
+// phishing vector (DOMPurify already strips <script>/on*=, but an
+// unsandboxed iframe still gets full script execution, same-origin-ish
+// access via document.domain tricks, top-level navigation, etc., inside
+// itself). This hook force-sets a restrictive sandbox on every iframe that
+// survives sanitization, keeping `allow-scripts`/`allow-same-origin`/
+// `allow-popups`/`allow-forms` (needed for interactive maps/video/oauth
+// popups) but deliberately omitting `allow-top-navigation` so an embedded
+// page can never redirect/hijack the parent tab.
+const IFRAME_SANDBOX_HOOK = (node: Element): void => {
+  if (node.nodeName === 'IFRAME') {
+    node.setAttribute('sandbox', 'allow-scripts allow-same-origin allow-popups allow-forms');
+    node.setAttribute('referrerpolicy', 'no-referrer');
+  }
+};
+
 export function purifyHtml(input: string): string {
-  return DOMPurify.sanitize(input || '', PURIFY_CONFIG as any) as unknown as string;
+  // Hook is added immediately before sanitize() and removed immediately
+  // after, scoped tightly to this single call -- so it can never leak onto
+  // (or accumulate duplicate copies across) any other DOMPurify.sanitize()
+  // call elsewhere in the app, and repeated purifyHtml() calls never stack
+  // multiple copies of the same hook.
+  DOMPurify.addHook('afterSanitizeAttributes', IFRAME_SANDBOX_HOOK);
+  try {
+    return DOMPurify.sanitize(input || '', PURIFY_CONFIG as any) as unknown as string;
+  } finally {
+    DOMPurify.removeHook('afterSanitizeAttributes', IFRAME_SANDBOX_HOOK as any);
+  }
 }
 
 export const HtmlBlock: UserComponent<HtmlBlockProps> = ({ code = '', style = {} }) => {
diff --git a/craft/src/components/basic/Navbar.toHtml.test.ts b/craft/src/components/basic/Navbar.toHtml.test.ts
index a9aca89..cc27a6a 100644
--- a/craft/src/components/basic/Navbar.toHtml.test.ts
+++ b/craft/src/components/basic/Navbar.toHtml.test.ts
@@ -5,28 +5,84 @@ const toHtml = (Navbar as any).toHtml;
 
 describe('Navbar.toHtml hamburger accessibility (F2.3)', () => {
   test('mobile toggle button has an accessible name, aria-expanded, and aria-controls', () => {
-    const { html } = toHtml({ showMobileMenu: true }, '');
+    const { html } = toHtml({ showMobileMenu: true }, '', 'node-nav1');
     expect(html).toMatch(/class="navbar-hamburger"[^>]*aria-label="Toggle navigation menu"/);
     expect(html).toMatch(/aria-expanded="false"/);
-    expect(html).toMatch(/aria-controls="navbar-links"/);
+    expect(html).toMatch(/aria-controls="[^"]+"/);
   });
 
   test('aria-controls target id exists on the links container', () => {
-    const { html } = toHtml({ showMobileMenu: true }, '');
-    expect(html).toContain('id="navbar-links"');
+    const { html } = toHtml({ showMobileMenu: true }, '', 'node-nav1');
+    const controls = html.match(/aria-controls="([^"]+)"/)![1];
+    expect(html).toContain(`id="${controls}"`);
   });
 
   test('toggle script flips aria-expanded on click', () => {
-    const { html } = toHtml({ showMobileMenu: true }, '');
+    const { html } = toHtml({ showMobileMenu: true }, '', 'node-nav1');
     expect(html).toMatch(/setAttribute\(['"]aria-expanded['"]/);
   });
 
   test('no mobile menu: no hamburger button emitted', () => {
-    const { html } = toHtml({ showMobileMenu: false }, '');
+    const { html } = toHtml({ showMobileMenu: false }, '', 'node-nav1');
     expect(html).not.toContain('navbar-hamburger');
   });
 });
 
+describe('Navbar.toHtml node-scoped ids/hover styles (M-1: two navbars must not collide)', () => {
+  test('no bare unscoped id="navbar-links" is emitted', () => {
+    const { html } = toHtml({ showMobileMenu: true }, '', 'node-nav1');
+    expect(html).not.toContain('id="navbar-links"');
+  });
+
+  test('two different node ids produce different links-container ids', () => {
+    const { html: html1 } = toHtml({ showMobileMenu: true }, '', 'node-nav1');
+    const { html: html2 } = toHtml({ showMobileMenu: true }, '', 'node-nav2');
+    const id1 = html1.match(/id="([^"]+)"/)![1];
+    const id2 = html2.match(/id="([^"]+)"/)![1];
+    expect(id1).not.toBe(id2);
+  });
+
+  test('aria-controls always equals the actual links-container id', () => {
+    const { html } = toHtml({ showMobileMenu: true }, '', 'node-nav1');
+    const controls = html.match(/aria-controls="([^"]+)"/)![1];
+    const linksId = html.match(/id="([^"]+)"/)![1];
+    expect(controls).toBe(linksId);
+  });
+
+  test('hover style selectors are scoped per-instance, not bare .navbar-link/.navbar-cta', () => {
+    const { html } = toHtml({ hoverColor: '#ff0000' }, '', 'node-nav1');
+    // A selector rule that STARTS the line with .navbar-link:hover (i.e. not
+    // preceded by a per-instance ancestor class) would be the old, unscoped,
+    // globally-colliding form.
+    expect(html).not.toMatch(/^\s*\.navbar-link:hover/m);
+    expect(html).not.toMatch(/^\s*\.navbar-cta:hover/m);
+    // still present, just scoped under a per-instance ancestor class
+    expect(html).toMatch(/\.navbar-link:hover/);
+    expect(html).toMatch(/\.[\w-]+ \.navbar-link:hover/);
+  });
+
+  test('two navbars with different hoverColor do not leak style onto each other (scoped selectors differ)', () => {
+    const { html: html1 } = toHtml({ hoverColor: '#ff0000' }, '', 'node-nav1');
+    const { html: html2 } = toHtml({ hoverColor: '#00ff00' }, '', 'node-nav2');
+    const scope1 = html1.match(/<style>\s*\.([\w-]+)\s/)![1];
+    const scope2 = html2.match(/<style>\s*\.([\w-]+)\s/)![1];
+    expect(scope1).not.toBe(scope2);
+    expect(html1).toContain(`.${scope1} .navbar-link:hover`);
+    expect(html2).toContain(`.${scope2} .navbar-link:hover`);
+  });
+
+  test('a normal single navbar still renders its hover style (visual output preserved)', () => {
+    const { html } = toHtml({ hoverColor: '#ff0000' }, '', 'node-nav1');
+    expect(html).toMatch(/:hover\s*\{\s*color:\s*#ff0000/);
+  });
+
+  test('same node id -> identical output across calls (deterministic)', () => {
+    const { html: html1 } = toHtml({ showMobileMenu: true }, '', 'node-nav1');
+    const { html: html2 } = toHtml({ showMobileMenu: true }, '', 'node-nav1');
+    expect(html1).toBe(html2);
+  });
+});
+
 describe('Navbar.toHtml XSS hardening (hoverColor/backgroundColor/ctaColor into <style>)', () => {
   test('a hoverColor value containing </style><script> is neutralized in the hover <style> block', () => {
     const malicious = '#fff}</style><script>alert(1)</script><style>{';
diff --git a/craft/src/components/basic/Navbar.tsx b/craft/src/components/basic/Navbar.tsx
index 6c789c8..7eaf233 100644
--- a/craft/src/components/basic/Navbar.tsx
+++ b/craft/src/components/basic/Navbar.tsx
@@ -2,7 +2,7 @@ import React, { CSSProperties, useState } from 'react';
 import { useNode, UserComponent } from '@craftjs/core';
 import { cssPropsToString } from '../../utils/style-helpers';
 import { useSiteDesign } from '../../state/SiteDesignContext';
-import { escapeHtml, escapeAttr, safeUrl, cssValue } from '../../utils/escape';
+import { escapeHtml, escapeAttr, safeUrl, cssValue, scopeId } from '../../utils/escape';
 
 /* ---------- Types ---------- */
 
@@ -210,7 +210,7 @@ Navbar.craft = {
 
 /* ---------- HTML export ---------- */
 
-(Navbar as any).toHtml = (props: NavbarProps, _childrenHtml: string) => {
+(Navbar as any).toHtml = (props: NavbarProps, _childrenHtml: string, nodeId?: string) => {
   // Sanitized once here -- these are raw string-interpolation sinks below
   // (hoverCol/bgColor go into a <style> block, the worst case: </style>
   // breakout -> arbitrary <script>), see task-cssxss-brief.md.
@@ -224,6 +224,19 @@ Navbar.craft = {
   const sticky = props.isSticky;
   const mobile = props.showMobileMenu;
   const logoUrl = props.logoUrl || '/';
+  const links0 = props.links || defaultLinks;
+
+  // M-1: deterministic AND unique per-instance scope, keyed on the Craft
+  // node id. Two Navbars on the same page previously emitted an identical
+  // fixed id="navbar-links" (invalid duplicate-id HTML, ambiguous
+  // aria-controls target) and unscoped `.navbar-link:hover`/`.navbar-cta:hover`
+  // rules in each instance's own <style> block -- since both blocks target
+  // the SAME global selector, the later one in the DOM silently overrides
+  // the earlier one's hover color/behavior for BOTH navbars. Scoping the
+  // links-container id and adding a per-instance class on the <nav> root
+  // (used to prefix the hover selectors) eliminates both collisions.
+  const scope = scopeId(nodeId, JSON.stringify(links0) + alignment + pad, 'nav');
+  const linksId = `${scope}_links`;
 
   const navStyle = cssPropsToString({
     display: 'flex',
@@ -272,21 +285,23 @@ Navbar.craft = {
   // via aria-expanded, kept in sync with the .navbar-open class by the
   // inline onclick handler.
   const hamburgerHtml = mobile
-    ? `\n    <button class="navbar-hamburger" aria-label="Toggle navigation menu" aria-expanded="false" aria-controls="navbar-links" onclick="var m=this.parentElement.querySelector('.navbar-links');var open=m.classList.toggle('navbar-open');this.setAttribute('aria-expanded', open ? 'true' : 'false');" style="display:none;background:none;border:none;cursor:pointer;padding:4px;flex-direction:column;gap:4px">
+    ? `\n    <button class="navbar-hamburger" aria-label="Toggle navigation menu" aria-expanded="false" aria-controls="${escapeAttr(linksId)}" onclick="var m=document.getElementById('${linksId}');var open=m.classList.toggle('navbar-open');this.setAttribute('aria-expanded', open ? 'true' : 'false');" style="display:none;background:none;border:none;cursor:pointer;padding:4px;flex-direction:column;gap:4px">
       <span style="display:block;width:24px;height:2px;background-color:${escapeAttr(textCol)}"></span>
       <span style="display:block;width:24px;height:2px;background-color:${escapeAttr(textCol)}"></span>
       <span style="display:block;width:24px;height:2px;background-color:${escapeAttr(textCol)}"></span>
     </button>`
     : '';
 
-  // Hover CSS
+  // Hover CSS -- scoped under `.${scope}` (a class on the <nav> root, added
+  // below) so it can only ever match THIS instance's links/CTA, never bleed
+  // into or get overridden by another Navbar instance's rules.
   const hoverCss = `<style>
-  .navbar-link:hover { color: ${hoverCol} !important; }
-  .navbar-cta:hover { filter: brightness(1.1); }${mobile ? `
+  .${scope} .navbar-link:hover { color: ${hoverCol} !important; }
+  .${scope} .navbar-cta:hover { filter: brightness(1.1); }${mobile ? `
   @media (max-width: 768px) {
-    .navbar-hamburger { display: flex !important; }
-    .navbar-links { display: none !important; position: absolute; top: 100%; left: 0; right: 0; flex-direction: column !important; background-color: ${bgColor}; padding: 12px 24px; gap: 12px !important; box-shadow: 0 4px 12px rgba(0,0,0,0.1); }
-    .navbar-links.navbar-open { display: flex !important; }
+    .${scope} .navbar-hamburger { display: flex !important; }
+    .${scope} .navbar-links { display: none !important; position: absolute; top: 100%; left: 0; right: 0; flex-direction: column !important; background-color: ${bgColor}; padding: 12px 24px; gap: 12px !important; box-shadow: 0 4px 12px rgba(0,0,0,0.1); }
+    .${scope} .navbar-links.navbar-open { display: flex !important; }
   }` : ''}
 </style>`;
 
@@ -309,9 +324,9 @@ Navbar.craft = {
 
   return {
     html: `${hoverCss}
-<nav${navStyle ? ` style="${navStyle}${mobile ? ';position:relative' : ''}"` : ''}>
+<nav class="${scope}"${navStyle ? ` style="${navStyle}${mobile ? ';position:relative' : ''}"` : ''}>
   ${logoHtml}${hamburgerHtml}
-  <div class="navbar-links" id="navbar-links" style="display:flex;align-items:center;gap:24px">
+  <div class="navbar-links" id="${linksId}" style="display:flex;align-items:center;gap:24px">
       ${linksHtmlWithClass}
   </div>
 </nav>`,
diff --git a/craft/src/components/sections/Gallery.toHtml.test.ts b/craft/src/components/sections/Gallery.toHtml.test.ts
index 23d617a..1f55cbb 100644
--- a/craft/src/components/sections/Gallery.toHtml.test.ts
+++ b/craft/src/components/sections/Gallery.toHtml.test.ts
@@ -93,3 +93,33 @@ describe('Gallery.toHtml deterministic + unique scope ids (thread node id, no Ma
     expect(html1).toBe(html2);
   });
 });
+
+describe('Gallery.toHtml lightbox focus management (M-2)', () => {
+  const props = { images: [{ src: '/a.jpg', alt: 'a' }], lightbox: true };
+
+  test('overlay includes a focusable close control with an accessible name and tabindex', () => {
+    const { html } = toHtml(props, '', 'node-gal1');
+    // A close control: a button (or the dialog container) with an accessible
+    // name (aria-label) and an explicit tabindex so it's keyboard-focusable.
+    expect(html).toMatch(/aria-label="[^"]*[Cc]lose[^"]*"[^>]*tabindex="-?\d+"|tabindex="-?\d+"[^>]*aria-label="[^"]*[Cc]lose[^"]*"/);
+  });
+
+  test('script saves document.activeElement on open (for focus restore)', () => {
+    const { html } = toHtml(props, '', 'node-gal1');
+    expect(html).toMatch(/document\.activeElement/);
+  });
+
+  test('script moves focus to the close control / dialog on open', () => {
+    const { html } = toHtml(props, '', 'node-gal1');
+    expect(html).toMatch(/\.focus\(\)/);
+  });
+
+  test('script restores the previously-saved focus on close', () => {
+    const { html } = toHtml(props, '', 'node-gal1');
+    // The close function references a stored "last focused element" variable
+    // and calls .focus() on it, not just moving focus INTO the dialog.
+    const closeFnMatch = html.match(/function\s+\w+_close\s*\(\)\s*\{[^}]*\}/);
+    expect(closeFnMatch).not.toBeNull();
+    expect(closeFnMatch![0]).toMatch(/\.focus\(\)/);
+  });
+});
diff --git a/craft/src/components/sections/Gallery.tsx b/craft/src/components/sections/Gallery.tsx
index c1c99c4..035d699 100644
--- a/craft/src/components/sections/Gallery.tsx
+++ b/craft/src/components/sections/Gallery.tsx
@@ -166,16 +166,37 @@ Gallery.craft = {
   let gridIdAttr = '';
   if (lightbox) {
     gridIdAttr = ` id="${galleryId}_grid"`;
+    // M-2: focus management for the lightbox dialog.
+    //  - OPEN: stash `document.activeElement` (the thumbnail that triggered
+    //    the open) in a module-scoped var, then move focus onto the close
+    //    button -- so a screen-reader/keyboard user lands inside the dialog
+    //    instead of focus staying on (or silently falling back to <body>)
+    //    behind the now-visible overlay.
+    //  - Tab trap: while the overlay is open, every Tab keypress is
+    //    intercepted and refocuses the close button (the dialog's only
+    //    focusable control besides Escape/click-to-close), so focus can
+    //    never wander out into the page content hidden behind the overlay.
+    //  - CLOSE (Escape, backdrop click, or the close button): restore focus
+    //    to the element stashed on open.
     lightboxHtml = `
   <div id="${galleryId}_overlay" role="dialog" aria-modal="true" aria-label="Image preview" onclick="${galleryId}_close()" style="display:none;position:fixed;top:0;left:0;width:100%;height:100%;background:rgba(0,0,0,0.9);z-index:9999;justify-content:center;align-items:center;cursor:pointer">
+    <button type="button" id="${galleryId}_closebtn" aria-label="Close preview" tabindex="-1" onclick="event.stopPropagation();${galleryId}_close()" style="position:absolute;top:16px;right:16px;width:36px;height:36px;border-radius:50%;border:none;background:rgba(255,255,255,0.15);color:#ffffff;font-size:20px;line-height:1;cursor:pointer;display:flex;align-items:center;justify-content:center">&times;</button>
     <img id="${galleryId}_img" src="" alt="" style="max-width:90%;max-height:90%;object-fit:contain;border-radius:8px" />
   </div>
   <script>
-function ${galleryId}_close(){document.getElementById('${galleryId}_overlay').style.display='none';}
+var ${galleryId}_lastFocus = null;
+function ${galleryId}_close(){
+  document.getElementById('${galleryId}_overlay').style.display='none';
+  if(${galleryId}_lastFocus && ${galleryId}_lastFocus.focus) ${galleryId}_lastFocus.focus();
+  ${galleryId}_lastFocus = null;
+}
 function ${galleryId}_open(src){
+  ${galleryId}_lastFocus = document.activeElement;
   var o = document.getElementById('${galleryId}_overlay');
   document.getElementById('${galleryId}_img').src = src;
   o.style.display = 'flex';
+  var c = document.getElementById('${galleryId}_closebtn');
+  if(c) c.focus();
 }
 document.getElementById('${galleryId}_grid').addEventListener('click', function(e){
   var t = e.target.closest('[data-lb-src]');
@@ -190,7 +211,14 @@ document.getElementById('${galleryId}_grid').addEventListener('keydown', functio
   ${galleryId}_open(t.getAttribute('data-lb-src'));
 });
 document.addEventListener('keydown', function(e){
-  if(e.key==='Escape'){ ${galleryId}_close(); }
+  var o = document.getElementById('${galleryId}_overlay');
+  if(!o || o.style.display==='none') return;
+  if(e.key==='Escape'){ ${galleryId}_close(); return; }
+  if(e.key==='Tab'){
+    e.preventDefault();
+    var c = document.getElementById('${galleryId}_closebtn');
+    if(c) c.focus();
+  }
 });
   </script>`;
   }
diff --git a/craft/src/hooks/useWhpApi.save.test.ts b/craft/src/hooks/useWhpApi.save.test.ts
index 96ef8ef..41c3975 100644
--- a/craft/src/hooks/useWhpApi.save.test.ts
+++ b/craft/src/hooks/useWhpApi.save.test.ts
@@ -1,6 +1,7 @@
 import { describe, test, expect } from 'vitest';
 import { buildSavePayload } from './useWhpApi';
 import { PageData } from '../types';
+import { DEFAULT_SITE_DESIGN } from '../state/SiteDesignContext';
 
 const pageA: PageData = { id: 'home', name: 'Home', slug: 'index', craftState: 'STORED_HOME' };
 const pageB: PageData = { id: 'page_2', name: 'About', slug: 'about', craftState: 'STORED_ABOUT' };
@@ -19,6 +20,8 @@ describe('buildSavePayload', () => {
       activePageId: '__header__',
       isEditingHeader: true,
       isEditingFooter: false,
+      headCode: DEFAULT_SITE_DESIGN.headCode,
+      design: DEFAULT_SITE_DESIGN,
     });
 
     // The fresh live canvas must be reflected in header_craft_state, not the stale stored one.
@@ -52,6 +55,8 @@ describe('buildSavePayload', () => {
       activePageId: '__footer__',
       isEditingHeader: false,
       isEditingFooter: true,
+      headCode: DEFAULT_SITE_DESIGN.headCode,
+      design: DEFAULT_SITE_DESIGN,
     });
 
     expect(payload.footer_craft_state).toBe('LIVE_FOOTER');
@@ -75,6 +80,8 @@ describe('buildSavePayload', () => {
       activePageId: 'home',
       isEditingHeader: false,
       isEditingFooter: false,
+      headCode: DEFAULT_SITE_DESIGN.headCode,
+      design: DEFAULT_SITE_DESIGN,
     });
 
     // Live canvas goes to the active page and top-level slots.
@@ -105,6 +112,8 @@ describe('buildSavePayload', () => {
       activePageId: 'home',
       isEditingHeader: false,
       isEditingFooter: false,
+      headCode: DEFAULT_SITE_DESIGN.headCode,
+      design: DEFAULT_SITE_DESIGN,
     });
 
     // The live edit must land in pages_craft_state[0] (index.html slot),
@@ -116,4 +125,26 @@ describe('buildSavePayload', () => {
     // The other page is untouched.
     expect(payload.pages_craft_state.find((p) => p.id === 'p2')?.craftState).toBe('STORED_ABOUT_2');
   });
+
+  test('head code + design tokens are included in the save payload', () => {
+    const design = { ...DEFAULT_SITE_DESIGN, headCode: '<meta name="x">' };
+
+    const payload = buildSavePayload({
+      siteId: 1,
+      siteName: 'Test Site',
+      liveCraftState: 'LIVE_PAGE_HOME',
+      pages: [pageA, pageB],
+      headerPage,
+      footerPage,
+      activePageId: 'home',
+      isEditingHeader: false,
+      isEditingFooter: false,
+      headCode: '<meta name="x">',
+      design,
+    });
+
+    expect(payload.head_code).toBe('<meta name="x">');
+    expect(payload.design).toEqual(design);
+    expect(payload.design.headCode).toBe('<meta name="x">');
+  });
 });
diff --git a/craft/src/hooks/useWhpApi.ts b/craft/src/hooks/useWhpApi.ts
index 2319c4d..464333b 100644
--- a/craft/src/hooks/useWhpApi.ts
+++ b/craft/src/hooks/useWhpApi.ts
@@ -2,6 +2,7 @@ import { useCallback } from 'react';
 import { useEditor } from '@craftjs/core';
 import { useEditorConfig } from '../state/EditorConfigContext';
 import { usePages } from '../state/PageContext';
+import { useSiteDesign, SiteDesign } from '../state/SiteDesignContext';
 import { exportBodyHtml } from '../utils/html-export';
 import { PageData } from '../types';
 
@@ -18,6 +19,10 @@ export interface BuildSavePayloadInput {
   isEditingHeader: boolean;
   /** True when the live canvas is showing the footer zone (activePageId === '__footer__'). */
   isEditingFooter: boolean;
+  /** Site-wide custom `<head>` code (also present on `design.headCode`). */
+  headCode: string;
+  /** Full site design tokens object -- lets load() restore colors/fonts/headCode. */
+  design: SiteDesign;
 }
 
 /**
@@ -45,6 +50,8 @@ export function buildSavePayload(input: BuildSavePayloadInput) {
     activePageId,
     isEditingHeader,
     isEditingFooter,
+    headCode,
+    design,
   } = input;
 
   const isPageActive = !isEditingHeader && !isEditingFooter;
@@ -173,6 +180,8 @@ export function buildSavePayload(input: BuildSavePayloadInput) {
     header_craft_state: headerCraftState,
     footer_craft_state: footerCraftState,
     pages_craft_state: pagesGrapesjs,
+    head_code: headCode,
+    design,
   };
 }
 
@@ -191,6 +200,7 @@ export function useWhpApi() {
     setPagesCraftState,
     setActivePageIdDirect,
   } = usePages();
+  const { design, updateDesign } = useSiteDesign();
 
   const save = useCallback(async () => {
     if (!isWHP || !whpConfig) return null;
@@ -210,6 +220,8 @@ export function useWhpApi() {
       activePageId,
       isEditingHeader,
       isEditingFooter,
+      headCode: design.headCode,
+      design,
     });
 
     const resp = await fetch(`${whpConfig.apiUrl}?action=save`, {
@@ -221,7 +233,7 @@ export function useWhpApi() {
       body: JSON.stringify(payload),
     });
     return resp.json();
-  }, [isWHP, whpConfig, query, pages, activePageId, headerPage, footerPage, isEditingHeader, isEditingFooter]);
+  }, [isWHP, whpConfig, query, pages, activePageId, headerPage, footerPage, isEditingHeader, isEditingFooter, design]);
 
   const publish = useCallback(async () => {
     if (!isWHP || !whpConfig) return null;
@@ -255,6 +267,17 @@ export function useWhpApi() {
     if (data.success && data.project) {
       const proj = data.project;
 
+      // Restore site design tokens (colors/fonts/headCode) so the editor
+      // reflects what was last saved. Prefer the full `design` object when
+      // present; fall back to just `head_code` for older project.json files
+      // saved before this field existed (backward-compatible: defaults for
+      // everything else).
+      if (proj.design && typeof proj.design === 'object') {
+        updateDesign(proj.design);
+      } else if (typeof proj.head_code === 'string') {
+        updateDesign({ headCode: proj.head_code });
+      }
+
       // Restore header craft state
       if (proj.header_craft_state) {
         setHeaderCraftState(typeof proj.header_craft_state === 'string'
@@ -300,7 +323,7 @@ export function useWhpApi() {
       }
     }
     return data;
-  }, [isWHP, whpConfig, actions, setHeaderCraftState, setFooterCraftState, setPagesCraftState, setActivePageIdDirect, isEditingHeader, isEditingFooter]);
+  }, [isWHP, whpConfig, actions, setHeaderCraftState, setFooterCraftState, setPagesCraftState, setActivePageIdDirect, isEditingHeader, isEditingFooter, updateDesign]);
 
   const uploadAsset = useCallback(
     async (file: File) => {
diff --git a/craft/src/state/PageContext.slug.test.tsx b/craft/src/state/PageContext.slug.test.tsx
index 5f807b8..e8d8ef9 100644
--- a/craft/src/state/PageContext.slug.test.tsx
+++ b/craft/src/state/PageContext.slug.test.tsx
@@ -2,7 +2,7 @@ import { describe, test, expect, vi, beforeEach, afterEach } from 'vitest';
 import React from 'react';
 import { createRoot, Root } from 'react-dom/client';
 import { act } from 'react-dom/test-utils';
-import { PageProvider, usePages, uniqueSlug } from './PageContext';
+import { PageProvider, usePages, uniqueSlug, nextPageId } from './PageContext';
 
 /* PageContext only needs `useEditor` from @craftjs/core (for query.serialize /
    actions.deserialize during page switches) — mock just that so PageProvider
@@ -15,11 +15,10 @@ vi.mock('@craftjs/core', () => ({
   }),
 }));
 
-/* addPage mints ids from `Date.now()`. Two adds inside the same test can land
-   in the same millisecond and collide on id, which is an existing, unrelated
-   bug (id collision, not slug collision) — out of scope here but it makes
-   these tests flaky since a colliding id defeats the "other pages" slug
-   lookup. Force distinct ids so the slug-dedupe assertions below are stable. */
+/* addPage mints ids via nextPageId() (timestamp + monotonic counter, M-3),
+   so same-millisecond calls no longer collide on id. Date.now() is still
+   pinned/advanced here for determinism across the slug-dedupe assertions
+   below, independent of wall-clock timing. */
 let dateNowSpy: ReturnType<typeof vi.spyOn>;
 beforeEach(() => {
   let counter = 1_700_000_000_000;
@@ -48,6 +47,23 @@ function unmount() {
   container.remove();
 }
 
+describe('nextPageId (M-3: no same-millisecond id collision)', () => {
+  test('two calls yield distinct ids even when Date.now() is pinned to a constant', () => {
+    const spy = vi.spyOn(Date, 'now').mockReturnValue(1_700_000_000_000);
+    try {
+      const id1 = nextPageId();
+      const id2 = nextPageId();
+      expect(id1).not.toBe(id2);
+    } finally {
+      spy.mockRestore();
+    }
+  });
+
+  test('ids are prefixed with "page_"', () => {
+    expect(nextPageId()).toMatch(/^page_/);
+  });
+});
+
 describe('uniqueSlug', () => {
   test('returns base unchanged when no collision', () => {
     expect(uniqueSlug('about', ['index', 'contact'])).toBe('about');
diff --git a/craft/src/state/PageContext.tsx b/craft/src/state/PageContext.tsx
index 0edbc6a..946b890 100644
--- a/craft/src/state/PageContext.tsx
+++ b/craft/src/state/PageContext.tsx
@@ -43,6 +43,20 @@ interface PageContextValue {
 const HEADER_ID = '__header__';
 const FOOTER_ID = '__footer__';
 
+// M-3: `page_${Date.now()}` alone collides when two pages are minted inside
+// the same millisecond (addPage called twice in quick succession, or two AI
+// replaceAllPages entries) -- then rename/delete/save operate on both pages
+// at once since they share an id. A module-scoped monotonic counter,
+// combined with the timestamp, guarantees uniqueness regardless of how many
+// ids are minted within the same millisecond. This is state/id-minting code
+// (not toHtml/export), so Date.now() here is fine -- see task-minors-brief.md.
+let pageIdCounter = 0;
+
+/** Mints a unique page id: timestamp (base36) + a monotonic per-process counter (base36). */
+export function nextPageId(): string {
+  return 'page_' + Date.now().toString(36) + '_' + (++pageIdCounter).toString(36);
+}
+
 const EMPTY_CANVAS =
   '{"ROOT":{"type":{"resolvedName":"Container"},"isCanvas":true,"props":{"style":{"minHeight":"100vh","backgroundColor":"#ffffff"},"tag":"div"},"displayName":"Container","custom":{},"hidden":false,"nodes":[],"linkedNodes":{}}}';
 
@@ -338,7 +352,7 @@ export const PageProvider: React.FC<{ children: ReactNode }> = ({ children }) =>
   const addPage = useCallback(
     (name: string, slug: string) => {
       const requestedSlug = slug || slugify(name);
-      const id = `page_${Date.now()}`;
+      const id = nextPageId();
 
       // Save current page first
       saveCurrentState();
@@ -452,7 +466,7 @@ export const PageProvider: React.FC<{ children: ReactNode }> = ({ children }) =>
       const slug = i === 0 ? 'index' : uniqueSlug(slugify(p.name), seenSlugs);
       seenSlugs.push(slug);
       return {
-        id: i === 0 ? 'home' : `page_${Date.now()}_${i}`,
+        id: i === 0 ? 'home' : nextPageId(),
         name: p.name,
         slug,
         craftState: treeToCraftState(p.tree),
diff --git a/craft/src/utils/escape.test.ts b/craft/src/utils/escape.test.ts
index b30a6e0..5a93970 100644
--- a/craft/src/utils/escape.test.ts
+++ b/craft/src/utils/escape.test.ts
@@ -71,6 +71,24 @@ describe('safeUrl', () => {
     expect(safeUrl(s)).toBe(s);
   });
 
+  test('M-5: blocks data:image/svg+xml (can execute script when navigated to directly)', () => {
+    expect(safeUrl('data:image/svg+xml,<svg onload=alert(1)>')).toBe('');
+  });
+
+  test('M-5: blocks data:image/svg+xml;base64 variant', () => {
+    expect(safeUrl('data:image/svg+xml;base64,PHN2ZyBvbmxvYWQ9YWxlcnQoMSk+')).toBe('');
+  });
+
+  test('M-5: blocks obfuscated (whitespace/case) data:image/svg+xml', () => {
+    expect(safeUrl('  DATA:IMAGE/SVG+XML,<svg onload=alert(1)>')).toBe('');
+  });
+
+  test('M-5: still allows other data:image/* types unchanged', () => {
+    expect(safeUrl('data:image/jpeg;base64,/9j/4AAQ')).toBe('data:image/jpeg;base64,/9j/4AAQ');
+    expect(safeUrl('data:image/gif;base64,R0lGOD')).toBe('data:image/gif;base64,R0lGOD');
+    expect(safeUrl('data:image/webp;base64,UklGR')).toBe('data:image/webp;base64,UklGR');
+  });
+
   test.each([
     'https://x.com/a?b=1&c=2',
     'http://x',
@@ -120,8 +138,24 @@ describe('scopeId', () => {
     expect(id1).not.toBe(id2);
   });
 
-  test('node id is slugified (non-alphanumeric characters stripped, lowercased)', () => {
-    expect(scopeId('Node ID! 123', 'seed', 'sb')).toBe('sb_nodeid123');
+  test('output is a valid CSS ident: prefix_hash', () => {
+    expect(scopeId('Node ID! 123', 'seed', 'sb')).toMatch(/^sb_[a-z0-9]+$/);
+  });
+
+  test('M-4: case-differing node ids do not collapse to the same scope (no case-fold collision)', () => {
+    expect(scopeId('AbC', 'seed', 'sb')).not.toBe(scopeId('abc', 'seed', 'sb'));
+  });
+
+  test('M-4: punctuation-differing node ids do not collapse to the same scope', () => {
+    expect(scopeId('a-b', 'seed', 'sb')).not.toBe(scopeId('ab', 'seed', 'sb'));
+  });
+
+  test('M-4: same input always yields the identical scope id', () => {
+    expect(scopeId('some-node-id', 'seed', 'sb')).toBe(scopeId('some-node-id', 'seed', 'sb'));
+  });
+
+  test('M-4: output always matches a valid CSS ident pattern', () => {
+    expect(scopeId('Weird!! Node--ID__123', 'seed', 'sb')).toMatch(/^[a-z]+_[a-z0-9]+$/i);
   });
 
   test('no nodeId (legacy 2-arg call sites) falls back to a deterministic hash of the seed, not Math.random', () => {
diff --git a/craft/src/utils/escape.ts b/craft/src/utils/escape.ts
index 335dbae..39bd953 100644
--- a/craft/src/utils/escape.ts
+++ b/craft/src/utils/escape.ts
@@ -36,7 +36,14 @@ export function escapeAttr(s: string): string {
 // Dangerous scheme prefixes, checked against a normalized copy with all
 // colons removed (see safeUrl) so that colon-splicing obfuscation like
 // "java:script:alert(1)" can't slip past a literal "javascript:" check.
-const DANGEROUS_SCHEME_PREFIXES = ['javascript', 'vbscript', 'datatext/html'];
+// M-5: `data:image/svg+xml` is blocked alongside `data:text/html` -- an SVG
+// document can carry an inline <script>/onload= just like an HTML document,
+// so it executes script when loaded as a document/navigation target (e.g. an
+// <a href> or window.open), even though it's nominally an "image" MIME type.
+// Other `data:image/*` types (png/jpeg/gif/webp, ...) stay allowed below --
+// only this specific scriptable subtype is blocked, regardless of a
+// trailing `;base64` or other parameters.
+const DANGEROUS_SCHEME_PREFIXES = ['javascript', 'vbscript', 'datatext/html', 'dataimage/svg+xml'];
 
 /** Decodes &#NN; and &#xNN; numeric HTML entities (used to obfuscate scheme names). */
 function decodeNumericEntities(s: string): string {
@@ -151,8 +158,14 @@ export function stableHash(seed: string): string {
  * available.
  */
 export function scopeId(nodeId: string | undefined, fallbackSeed: string, prefix: string): string {
-  const slug = (nodeId || '').toString().toLowerCase().replace(/[^a-z0-9]+/g, '');
-  return `${prefix}_${slug || stableHash(fallbackSeed)}`;
+  // M-4: hash the raw node id (via the same djb2 `stableHash` used for the
+  // fallback path below) rather than lowercasing + stripping punctuation
+  // into a slug. A slug collapses distinct ids that differ only by
+  // case/punctuation (e.g. "AbC" and "abc", or "a-b" and "ab") onto the same
+  // scope; hashing the untouched string keeps them distinct while staying
+  // deterministic and producing a valid CSS ident (prefix + '_' + [a-z0-9]+).
+  const seed = (nodeId || '').toString();
+  return `${prefix}_${stableHash(seed || fallbackSeed)}`;
 }
 
 // Shared enum allowlists for `toHtml` attribute sinks fed by props that are