Sidebar

The primary app navigation — a 256px rail on the tinted sidebar surface, one level of nesting at most.

The active row is a 4% wash plus medium weight — never a coloured pill or a left accent bar.
Exactly one item is active, derived from the route. Every item is a route.
Icon then label, one icon set, one size. Never mix items with and without icons.
Badges sit at the trailing edge, count one predicate over one array, and render nothing at zero.
Two or more groups each get an uppercase label; a single group gets none.