Nothing in the app respected prefers-reduced-motion — the kit's
data-open/closed animations, the skeleton pulse, and the sidebar width
transition all ran unconditionally. Add a global base-layer rule that
collapses animation/transition durations to a single frame when the OS
asks for reduced motion; one rule covers current and future additions.
Add overscroll-y-contain to the scrollable modal/popup surfaces
(DrawerContent, SelectContent, ComboboxPopup) so flicking past the end
of their content no longer chain-scrolls the page beneath, and to
AlertDialogContent for when it gains scrollable content.
Verified in the built CSS: the media query and
overscroll-behavior-y:contain both compile into dist/assets.
Closes#71
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>