Mobile only (<=639px / coarse pointers); desktop keeps its behaviour.
Foundation
- lib/motion.ts owns the spring presets (snappy/gentle/sheet), durations,
easings and variants (screens, tabs, wizard steps, list stagger).
- Native-feel CSS: press feedback scales every button, card, chip, tab,
row and summary to 0.96 with a spring-like cubic-bezier on transform
(scoped to phones/coarse pointers), tap-highlight off, touch-action
manipulation, chrome text non-selectable, reduced motion drops it.
- App shell fades in once on launch; the study feed fades in on phones.
Applied
- Tab bar: sliding active pill (shared layoutId) + icon bounce.
- Study Decks/Homework, language toggle, difficulty and size pickers:
the same gliding highlight, gated so desktop keeps the old styling.
- Route content enters direction-aware (deeper = from the right, back =
from the left, same-depth = crossfade) via RouteTransition on the
library/create/homework content columns; library tab switches
crossfade; wizard steps slide forward/backward (reduced motion safe).
- Library: cards fade up in a capped stagger on first load, glide with
layout animations and shrink away on delete (AnimatePresence).
- Study feed: correct feedback pulses, wrong shakes, the progress bar
settles with a spring curve, score and XP count up on the results.
- Settings sheet uses the sheet spring; the drawer now follows the
finger and closes on release velocity, like the sheet.
- Generation progress: the stage message fades/slides between stages;
the icon keeps its gentle wobble; the feed fades in on hand-off.
Skipped, on purpose: LazyMotion (the sliding highlights need layout
animations = domMax, same features the current import already has);
route exit animations (the App Router unmounts the outgoing page —
exits are handled by in-page AnimatePresence); replacing the study
feed's native scroll-snap with finger-follow drag (would fight the
platform scroller); finger-follow height animation for native <details>
expanders.
Verified: animation suite 8/8 (reduced motion + 4x-CPU-throttled trace:
no long tasks, CLS 0.0000), regression 74/74, mobile 52/52, declutter
116/116, i18n 25/25. Lint + build clean. SW freezmo-v21.
Martin Dvorak
374752c59e