@@ -67,6 +67,8 @@ const FIT_MAX_ZOOM = 1
  * just fits a 1750px frame and only overflows on narrower ones.
  */
 const FIT_MIN_ZOOM = 0.64
+/** Static overviews must fit on phones, where cropping can leave no visible cards. */
+const REDUCED_MOTION_FIT_MIN_ZOOM = 0.05
 const FIT_DURATION_MS = 600
 const EMPTY_IDS: ReadonlySet<string> = new Set()
 
@@ -616,7 +618,7 @@ function ProductionWorkflowCanvas({
       const zoom = Math.min(
         FIT_MAX_ZOOM,
         Math.max(
-          FIT_MIN_ZOOM,
+          reducedMotion ? REDUCED_MOTION_FIT_MIN_ZOOM : FIT_MIN_ZOOM,
           Math.min(
             (width - 2 * FIT_PADDING_PX) / bounds.width,
             (height - 2 * FIT_PADDING_PX) / bounds.height
@@ -747,7 +749,7 @@ function ProductionWorkflowCanvas({
         onNodesChange={handleNodesChange}
         nodeTypes={NODE_TYPES}
         edgeTypes={EDGE_TYPES}
-        minZoom={MIN_ZOOM}
+        minZoom={scripted && reducedMotion ? REDUCED_MOTION_FIT_MIN_ZOOM : MIN_ZOOM}
         maxZoom={MAX_ZOOM}
         defaultViewport={{ x: 0, y: 48, zoom: FOCUSED_NODE_MIN_ZOOM }}
         panOnDrag={interactive}
 
@@ -90,6 +90,19 @@ function click(label: string) {
   act(() => button.dispatchEvent(new MouseEvent('click', { bubbles: true })))
 }
 
+function announcement(): HTMLElement {
+  const element = host.querySelector<HTMLElement>('[data-test-announcement]')?.parentElement
+  if (!element) throw new Error('Missing announcement')
+  return element
+}
+
+function scrollTo(position: number) {
+  act(() => {
+    host.scrollTop = position
+    host.dispatchEvent(new Event('scroll'))
+  })
+}
+
 function unmount() {
   act(() => root.unmount())
   mounted = false
@@ -103,8 +116,10 @@ beforeEach(() => {
   vi.stubGlobal('ResizeObserver', ControlledResizeObserver)
   vi.stubGlobal('IntersectionObserver', ControlledIntersectionObserver)
   vi.spyOn(HTMLElement.prototype, 'getBoundingClientRect').mockImplementation(function () {
-    return new DOMRect(0, 0, 1440, this.tagName === 'HEADER' ? headerHeight : 0)
+    const height = this.tagName === 'HEADER' ? headerHeight : 32
+    return new DOMRect(0, 0, 1440, height)
   })
+  vi.spyOn(HTMLElement.prototype, 'offsetHeight', 'get').mockReturnValue(32)
 
   host = document.createElement('div')
   host.style.overflowY = 'scroll'
@@ -114,13 +129,21 @@ beforeEach(() => {
   Object.defineProperties(host, {
     offsetWidth: { value: 1440 },
     clientWidth: { value: 1420 },
+    scrollHeight: { value: 2000 },
+    clientHeight: { value: 800 },
   })
   document.body.append(host)
   root = createRoot(host)
   mounted = true
   act(() => {
     root.render(
-      <NavbarShell>
+      <NavbarShell
+        announcement={
+          <a href='/blog/update' data-test-announcement>
+            Read update
+          </a>
+        }
+      >
         <MenuControls />
       </NavbarShell>
     )
@@ -136,15 +159,19 @@ afterEach(() => {
 
 describe('NavbarShell menu positioning and scroll containment', () => {
   it('publishes the current header height before a resize and updates it when header content changes', () => {
-    expect(header().style.getPropertyValue('--landing-header-height')).toBe('104px')
+    expect(header().style.getPropertyValue('--landing-header-height')).toBe(
+      'calc(104px - var(--landing-announcement-offset, 0px))'
+    )
     expect(host.style.scrollPaddingTop).toBe('104px')
     expect(resizeObservers).toHaveLength(1)
     expect(resizeObservers[0].observe).toHaveBeenCalledWith(header())
 
     headerHeight = 76
     act(() => resizeObservers[0].resize(header()))
 
-    expect(header().style.getPropertyValue('--landing-header-height')).toBe('76px')
+    expect(header().style.getPropertyValue('--landing-header-height')).toBe(
+      'calc(76px - var(--landing-announcement-offset, 0px))'
+    )
     expect(host.style.scrollPaddingTop).toBe('76px')
     expect(host.scrollTop).toBe(320)
   })
@@ -196,3 +223,82 @@ describe('NavbarShell menu positioning and scroll containment', () => {
     expect(host.style.paddingRight).toBe('12px')
   })
 })
+
+describe('NavbarShell announcement scroll behavior', () => {
+  it('hides on downward scroll and restores on upward scroll without changing the scroll position', () => {
+    expect(announcement().hasAttribute('inert')).toBe(false)
+
+    scrollTo(400)
+
+    expect(announcement().hasAttribute('inert')).toBe(true)
+    expect(announcement().getAttribute('aria-hidden')).toBe('true')
+    expect(host.style.scrollPaddingTop).toBe('104px')
+    expect(host.scrollTop).toBe(400)
+
+    scrollTo(380)
+
+    expect(announcement().hasAttribute('inert')).toBe(false)
+    expect(host.style.scrollPaddingTop).toBe('104px')
+    expect(host.scrollTop).toBe(380)
+  })
+
+  it('ignores small direction changes but accumulates slow scrolling', () => {
+    scrollTo(324)
+    expect(announcement().hasAttribute('inert')).toBe(false)
+    scrollTo(329)
+    expect(announcement().hasAttribute('inert')).toBe(true)
+    scrollTo(326)
+    expect(announcement().hasAttribute('inert')).toBe(true)
+    scrollTo(320)
+    expect(announcement().hasAttribute('inert')).toBe(false)
+  })
+
+  it('keeps the banner visible near the top and ignores overscroll bounce at both ends', () => {
+    scrollTo(400)
+    scrollTo(-30)
+    expect(announcement().hasAttribute('inert')).toBe(false)
+    scrollTo(10)
+    expect(announcement().hasAttribute('inert')).toBe(false)
+
+    scrollTo(1200)
+    scrollTo(1250)
+    scrollTo(1200)
+    expect(announcement().hasAttribute('inert')).toBe(true)
+    scrollTo(1180)
+    expect(announcement().hasAttribute('inert')).toBe(false)
+  })
+
+  it('keeps the header stationary while a navigation menu is open', () => {
+    scrollTo(400)
+    click('Open mobile')
+    scrollTo(300)
+    expect(announcement().hasAttribute('inert')).toBe(true)
+    expect(host.style.scrollPaddingTop).toBe('104px')
+
+    click('Close mobile')
+    scrollTo(280)
+    expect(announcement().hasAttribute('inert')).toBe(false)
+  })
+
+  it('does not hide a focused announcement link', () => {
+    host.querySelector<HTMLElement>('[data-test-announcement]')?.focus()
+    scrollTo(400)
+    expect(announcement().hasAttribute('inert')).toBe(false)
+  })
+
+  it('restores the full header if native focus scrolling reaches the top while a menu is open', () => {
+    scrollTo(400)
+    click('Open mobile')
+    scrollTo(0)
+
+    expect(announcement().hasAttribute('inert')).toBe(false)
+    expect(host.style.scrollPaddingTop).toBe('104px')
+    expect(host.style.overflowY).toBe('hidden')
+  })
+
+  it('removes the scroll listener when the shell unmounts', () => {
+    const removeListener = vi.spyOn(host, 'removeEventListener')
+    unmount()
+    expect(removeListener).toHaveBeenCalledWith('scroll', expect.any(Function))
+  })
+})
@@ -22,13 +22,15 @@ interface NavbarFrostContextValue {
 }
 
 const NavbarFrostContext = createContext<NavbarFrostContextValue | null>(null)
+const SCROLL_DIRECTION_THRESHOLD = 8
 
 /** Lets each nav surface report its open state so the shell can coordinate shared effects. */
 export function useNavbarFrost(): NavbarFrostContextValue | null {
   return use(NavbarFrostContext)
 }
 
 interface NavbarShellProps {
+  announcement?: ReactNode
   children: ReactNode
 }
 
@@ -39,8 +41,7 @@ interface NavbarShellProps {
  * At the very top the bar uses the same solid canvas token as the hero, so it is
  * visually seamless while still preventing route content from painting through
  * the sticky header. A 1px sentinel at the top of the landing shell's internal
- * scroll port is watched by an {@link IntersectionObserver} - no scroll listener
- * and no per-frame work. Past that point the bar gains the shared
+ * scroll port is watched by an {@link IntersectionObserver}. Past that point the bar gains the shared
  * {@link NAVBAR_GLASS_SURFACE} (`--bg` at 92% via `color-mix` plus a strong 40px
  * backdrop blur) - a white/glass surface built entirely from the platform's
  * light tokens, not invented colors.
@@ -51,8 +52,12 @@ interface NavbarShellProps {
  * while the fill still fades, so the frost appears smoothly without the jitter.
  *
  * The measured header height anchors the desktop panel and bounds the mobile
- * sheet, including changes to the announcement strip or text sizing. The same
- * height offsets native page and hash scrolling inside the landing scroll port.
+ * sheet, including changes to the announcement strip or text sizing. Native
+ * page and hash scrolling reserve the full height so changing banner visibility
+ * does not move the scroll anchor and leaves room for the banner to return.
+ * Scrolling down slides the announcement above the viewport; scrolling up
+ * restores it. Moving the sticky inset preserves document flow and scroll
+ * position. Menu offsets use only the visible portion of the header.
  *
  * Both navigation surfaces report open state through {@link NavbarFrostContext}.
  * While either is open, the shell locks its actual scroll port, preserves the
@@ -75,10 +80,12 @@ interface NavbarShellProps {
  * Only this shell hydrates; the nav content is server-rendered and passed through
  * as {@link children}, so the wordmark and links stay zero-hydration and crawlable.
  */
-export function NavbarShell({ children }: NavbarShellProps) {
+export function NavbarShell({ announcement, children }: NavbarShellProps) {
   const sentinelRef = useRef<HTMLDivElement>(null)
   const headerRef = useRef<HTMLElement>(null)
+  const announcementRef = useRef<HTMLDivElement>(null)
   const [scrolled, setScrolled] = useState(false)
+  const [announcementHidden, setAnnouncementHidden] = useState(false)
   const [menuOpenBySource, setMenuOpenBySource] = useState({ desktop: false, mobile: false })
   const menuOpen = menuOpenBySource.desktop || menuOpenBySource.mobile
 
@@ -88,24 +95,50 @@ export function NavbarShell({ children }: NavbarShellProps) {
     if (!header || !scrollPort) return
 
     const previousScrollPaddingTop = scrollPort.style.scrollPaddingTop
-    let previousHeight = 0
     const updateHeight = () => {
       const height = header.getBoundingClientRect().height
-      if (height === previousHeight) return
-      previousHeight = height
-      header.style.setProperty('--landing-header-height', `${height}px`)
+      const announcementHeight = announcementRef.current?.getBoundingClientRect().height ?? 0
+      header.style.setProperty('--landing-announcement-height', `${announcementHeight}px`)
+      header.style.setProperty(
+        '--landing-header-height',
+        `calc(${height}px - var(--landing-announcement-offset, 0px))`
+      )
       scrollPort.style.scrollPaddingTop = `${height}px`
     }
 
     updateHeight()
     const observer = new ResizeObserver(updateHeight)
     observer.observe(header)
+    if (announcementRef.current) observer.observe(announcementRef.current)
     return () => {
       observer.disconnect()
       scrollPort.style.scrollPaddingTop = previousScrollPaddingTop
     }
   }, [])
 
+  useEffect(() => {
+    const scrollPort = sentinelRef.current?.parentElement
+    const banner = announcementRef.current
+    if (!scrollPort || !banner) return
+
+    const scrollPosition = () =>
+      Math.max(0, Math.min(scrollPort.scrollTop, scrollPort.scrollHeight - scrollPort.clientHeight))
+    let previousPosition = scrollPosition()
+    const onScroll = () => {
+      const position = scrollPosition()
+      const delta = position - previousPosition
+      const nearTop = position <= banner.offsetHeight
+      if (!nearTop && (menuOpen || Math.abs(delta) < SCROLL_DIRECTION_THRESHOLD)) return
+
+      previousPosition = position
+      if (banner.contains(document.activeElement)) return
+      setAnnouncementHidden(!nearTop && delta > 0)
+    }
+
+    scrollPort.addEventListener('scroll', onScroll, { passive: true })
+    return () => scrollPort.removeEventListener('scroll', onScroll)
+  }, [menuOpen])
+
   useEffect(() => {
     const sentinel = sentinelRef.current
     if (!sentinel) return
@@ -166,7 +199,13 @@ export function NavbarShell({ children }: NavbarShellProps) {
       <header
         ref={headerRef}
         data-landing-header
-        className='sticky top-0 z-50 [--landing-header-height:calc(1.95rem_+_62px)]'
+        className={cn(
+          'sticky z-50 transition-[top] duration-200 ease-out [--landing-announcement-height:1.95rem] [--landing-header-height:calc(1.95rem_+_62px)] motion-reduce:transition-none',
+          announcementHidden
+            ? '-top-[var(--landing-announcement-height)] [--landing-announcement-offset:var(--landing-announcement-height)]'
+            : 'top-0 [--landing-announcement-offset:0px]',
+          menuOpen && 'transition-none'
+        )}
       >
         <div
           aria-hidden='true'
@@ -175,6 +214,11 @@ export function NavbarShell({ children }: NavbarShellProps) {
             scrolled || menuOpen ? NAVBAR_GLASS_SURFACE : 'bg-[var(--bg)]'
           )}
         />
+        {announcement && (
+          <div ref={announcementRef} inert={announcementHidden} aria-hidden={announcementHidden}>
+            {announcement}
+          </div>
+        )}
         {children}
       </header>
       <div
 
@@ -34,8 +34,7 @@ interface NavbarProps {
 
 export function Navbar({ stars }: NavbarProps) {
   return (
-    <NavbarShell>
-      <AnnouncementBanner />
+    <NavbarShell announcement={<AnnouncementBanner />}>
       <nav
         aria-label='Primary navigation'
         itemScope
 
@@ -46,7 +46,6 @@ let root: Root
 
 beforeEach(() => {
   resizeObserver = null
-  vi.stubGlobal('CSS', { supports: vi.fn(() => true) })
   vi.stubGlobal('ResizeObserver', ResizeObserverMock)
   container = document.createElement('div')
   document.body.appendChild(container)
@@ -115,14 +114,11 @@ describe('calculateFitScale', () => {
 
 describe('ResponsiveDesignStage', () => {
   it.each([
-    { width: 280, height: 400, supportsZoom: true },
-    { width: 280, height: 400, supportsZoom: false },
-    { width: 350, height: 340, supportsZoom: true },
-    { width: 350, height: 340, supportsZoom: false },
+    { width: 280, height: 400 },
+    { width: 350, height: 340 },
   ])(
-    'fits an uncapped $width × $height stage with zoom support: $supportsZoom',
-    ({ width, height, supportsZoom }) => {
-      vi.stubGlobal('CSS', { supports: vi.fn(() => supportsZoom) })
+    'scales text and layout together in an uncapped $width × $height stage',
+    ({ width, height }) => {
       act(() => {
         root.render(
           createElement(
@@ -140,13 +136,13 @@ describe('ResponsiveDesignStage', () => {
       const observer = resizeObserver
 
       act(() => observer.deliver(width * 2, height * 1.5))
-      expect(surface.style.zoom).toBe(supportsZoom ? '1.5' : '1')
-      expect(surface.style.transform).toBe(supportsZoom ? '' : 'scale(1.5)')
+      expect(surface.style.getPropertyValue('zoom')).toBe('')
+      expect(surface.style.transform).toBe('scale(1.5)')
       expect(surface.style.opacity).toBe('1')
 
       act(() => observer.deliver(width / 2, height * 2))
-      expect(surface.style.zoom).toBe(supportsZoom ? '0.5' : '1')
-      expect(surface.style.transform).toBe(supportsZoom ? '' : 'scale(0.5)')
+      expect(surface.style.getPropertyValue('zoom')).toBe('')
+      expect(surface.style.transform).toBe('scale(0.5)')
       expect(surface.style.opacity).toBe('1')
     }
   )
@@ -170,13 +166,13 @@ describe('ResponsiveDesignStage', () => {
 
     act(() => observer.deliver(500, 250))
     expect(surface.style.opacity).toBe('1')
-    expect(surface.style.zoom).toBe('0.5')
+    expect(surface.style.transform).toBe('scale(0.5)')
 
     act(() => observer.deliver(0, 250))
     expect(surface.style.opacity).toBe('0')
 
     act(() => observer.deliver(500, 250))
     expect(surface.style.opacity).toBe('1')
-    expect(surface.style.zoom).toBe('0.5')
+    expect(surface.style.transform).toBe('scale(0.5)')
   })
 })