App Shell
The floating workspace shell: textured brand ground, transparent sidebar rail with white-pill nav, and the page content floating as one brand card. The header and footer are slots — apps/web passes its data-bound workspace selector, trial card, and user menu.
Floating shell
Default carded layout. The sidebar collapses to an icon rail (toggle or Cmd+B), sections expand in place, and the active leaf gets the solid white pill with the blue accent bar.
Full-bleed (carded={false})
Surfaces that compose their own floating panels (e.g. chat) opt out of the page card and own the full inset.