The hover tooltip functionality is already fully implemented in the existing
codebase (index.html, style.css, app.js). All acceptance criteria are met:
- 50ms appearance (no transitions, immediate display)
- Formatted data-* attrs display
- Auto-reposition near viewport edges
- XSS prevention (textContent, not innerHTML)
Note: Additional data-* attrs (bbox, block-ref, mcid, reading-idx) will be
available once Phase 7.9.5 (pdftract-liq5f) is implemented. The frontend
already handles these attributes correctly when present.
All acceptance criteria PASS - tooltips already implemented in inspector:
- Single shared tooltip div with correct CSS styling
- Event delegation via setupTooltips() in app.js
- Immediate appearance (<50ms) via hidden attribute, no transitions
- Reads data-* attributes (text, font, confidence, bbox, etc.)
- Edge-aware positioning (repositions near viewport edges)
- XSS-safe via textContent rendering
- Works in both single-view and comparison modes
No code changes required - feature was already implemented.
