…ock, RangeSlider, Pagination, SegmentedControl

Combobox
- Remove misused role="combobox" from trigger button (disclosure button pattern, not ARIA combobox)
- Add aria-controls linking trigger → listbox; add id on listbox element
- Add id on each option; add aria-activedescendant + aria-autocomplete="list" to search input
  so screen readers announce the highlighted option during keyboard navigation

TagInput
- Wrap in role="group" with aria-label for composite widget semantics
- Label the text input via aria-label; add aria-invalid + aria-describedby for error
- Add role="status" aria-live="polite" region to announce tag add/remove to screen readers
- Render inline error message element linked by aria-describedby

RangeSlider
- Move aria-invalid from wrapper div to the focusable <input type="range">
- Add aria-describedby on input pointing to rendered error paragraph
- Add visible error message element; remove stale aria-invalid from wrapper

Carousel
- Add aria-label (default "Content slideshow") to role="region" so it is a meaningful landmark

Pagination
- Explicit aria-hidden="true" on PaginationEllipsis (was bare aria-hidden)

SegmentedControl
- Wrap icon in aria-hidden="true" span to prevent double-announcement alongside label text

CodeBlock (line numbers)
- Change line-number <td> to <th scope="row"> for correct table semantics
- Add visually-hidden <caption> so AT announces the table purpose

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…ements

Adds optional `index` (0-based) and `total` props to CarouselItem.
When both are provided, aria-label="N of total" is rendered on the
role="group" slide element so screen readers announce slide position
("1 of 5", "2 of 5", etc.) per the ARIA carousel pattern.

Existing usage without these props is unaffected — aria-label is only
applied when both values are present.

Usage:
  {items.map((item, i) => (
    <CarouselItem key={item.id} index={i} total={items.length}>
      ...
    </CarouselItem>
  ))}

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

- TextLink: add sanitizeHref() with protocol allow-list (https, http, mailto,
  tel, relative paths). Dangerous protocols like javascript: and data: render
  as inert anchors (no href attribute).
- Markdown: apply sanitizeHref() at parse boundary before passing extracted
  URLs to TextLink — closes the XSS path through untrusted markdown content.
- Combobox: restore role="combobox" on trigger button (select-only combobox
  ARIA pattern) — fixes 31 test failures from incorrect a11y removal.
- Security report: reports/security_best_practices_report.md (OWASP A03).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Typography (baseline-ui rules):
- Markdown h1/h2/h3: add text-balance
- Markdown p: add text-pretty
- EmptyMessage h3: add text-balance
- EmptyMessage description p: add text-pretty
- ErrorBoundary h3: add text-balance
- Modal h2: add text-balance
- Card h4 (CardTitle): add text-balance via cn default

Layout:
- toast: max-h-screen → max-h-dvh (dynamic viewport height for mobile browsers)

Note: toast z-[100] flagged as a design-system concern (no built-in z-100
Tailwind token) — deferred to a separate design-system discussion.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Wraps the search state in useDeferredValue so the input field updates
immediately while the filtered options list can defer its re-render.
This keeps the combobox responsive when filtering large option lists.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Adds a semantic zIndex extension to the Tailwind preset, backed by the
existing --ds-z-* CSS custom properties from enhanced.css. Enables use
of z-modal-backdrop, z-modal, z-popover, z-tooltip, etc. as Tailwind
utilities instead of arbitrary z-[n] values.

- toast: z-[100] → z-modal-backdrop (first component migrated)

Note: existing components using z-50 for overlays/popovers/tooltips
pre-date this scale and remain at z-50 for now. A broader migration
to z-popover / z-tooltip is tracked as a follow-up.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Documents that ChartStyle uses an unsafe innerHTML escape hatch,
which inputs are sanitized (id, color values, config keys), and
that ChartConfig must be developer-controlled — not populated from
untrusted user input without explicit sanitization.

Closes SEC-03 from the audit report.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

- alert: add warning/success/info variants wired to existing status tokens
- alert: fix AlertTitle ref type (HTMLParagraphElement → HTMLHeadingElement)
- button: remove aria-invalid on <button> (invalid per ARIA spec)
- button: add micro-interactions (hover scale 1.01 / active scale 0.98) with motion-reduce overrides
- tokens: add transitionDuration and transitionTimingFunction to Tailwind preset (ds-micro → ds-complex, ds-swift/standard/ease-*)
- focus: scope focusVisibleCSS from bare :focus-visible to .ds-focusable / [data-ds-focusable] to prevent global style conflicts; add @warning JSDoc

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…ecurity report

- testing/utils: pass `baseElement.ownerDocument` to userEvent.setup() instead of
  relying on globalThis.document, which user-event@14 captures at module load time
  (before jsdom initialises in vitest 4). Root cause: defaultOptionsDirect caches
  globalThis.document=undefined; our fix bypasses the cache using the live DOM.
- Add happy-dom devDep (installed, kept for optional future use)
- reports: append 2026-03-23 security review findings (S-01 to S-04) to existing report

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

  Wire the March 2026 agent-UI contract into policy, migrate protected settings
  and chat surfaces onto semantic design-system patterns, expand exemplar and
  visual coverage, and ratchet additional Storybook learning surfaces away from
  foundation-token usage.

  Co-authored-by: Codex <noreply@openai.com>
  EOF

  git pull --rebase origin main
  git switch -c codex/agent-ui-hardening-mar-2026
  git push -u origin codex/agent-ui-hardening-mar-2026
  gh pr create --fill --base main --head codex/agent-ui-hardening-mar-2026

  Update stale ChatSidebar, Button, Select, ScrollArea, and touch-target policy
  tests to match the new semantic sizing and focus-ring classes introduced by the
  design-system hardening pass.

  Co-authored-by: Codex <noreply@openai.com>
  EOF

  git push -u origin codex/agent-ui-hardening-mar-2026
  gh pr create --fill --base main --head codex/agent-ui-hardening-mar-2026

Move the always-on exemplar evaluation step from the Ubuntu web build to the
macOS build lane so the Storybook and fullscreen chat/settings screenshots are
checked on the same platform their committed baselines were recorded on.

Co-authored-by: Codex <noreply@openai.com>