75efeb1474
Fixes info modal positioning to be perfectly centered on mobile devices in all orientations. ISSUE: - Info modal was not centered on mobile viewports - User reported "pop-up of information in mobile it is not centered" - Modal positioning relied on inset:0 + margin:auto which doesn't work consistently on mobile devices FIX: - Added explicit mobile centering using transform translate(-50%, -50%) - Position: top: 50%, left: 50% with transform centering - Applied to all modals: info, keyboard shortcuts, and PDF download - Added mobile-specific fade-in animation preserving centering - Constrained modal to viewport with calc(100vw - 2rem) width/height Files modified: - static/css/04-interactive/_modals.css - Mobile centering for all modals - tests/mjs/58-modal-centering-test.mjs - Validation test Test results: ✅ Portrait (375×667): Perfect center - 0px offset ✅ Landscape (667×375): Perfect center - 0px offset ✅ Modal center matches viewport center exactly