- Skip-to-content link for keyboard users (sr-only/focus:not-sr-only pattern)
- aria-expanded and aria-haspopup on Tracker menu dropdown
- aria-label on footer, role='main' and aria-labelledby on layout wrapper
- Main content wrapped in <main> with unique id from React useId()
- Fixed build error: useId imported from react, not react-router-dom
- Hudson security audit: 5/5 PASS (no XSS, no DOM clobbering, no injection)