The mobile bottom bar now draws a single absolutely positioned grape pill (top 10 px, height 42 px) behind its items and implements handoff Motion section 1: on a tab change it slides the pill from the old item's left and width to the new one's over 420 ms on the --ease-spring curve, FLIPs every moved item with the same timing, and fades the new label in (220 ms ease-out after 120 ms). Icon colour crossfades via transition color .2s. Under prefers-reduced-motion the pill jumps with no animation. The pill is re-placed on resize and once document.fonts.ready resolves. Each item keeps the full 62 px bar height as its tap target. Maestro task d340ae00-3c2a-48cf-9ac6-35e0b8ed5a7c Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>