Cart Sheet

The mini cart on your shadcn Sheet: a bag button with a count that turns over, and a sheet that grows out of it as a circle and folds back into it (Motion; a fade under reduced motion). Ruled header, body and footer bands — the lines are the only scroller, with soft edges instead of a scrollbar — and a footer with free-delivery progress, the subtotal and checkout. Focus is trapped and handed back to the bag button; lines are keyed by id, so a cart update never remounts one mid-undo, and the subtotal follows what the shopper sees before your cart catches up. Compound, through useCartSheet().