Components

AppShell

The application frame: a collapsible sidebar, a menu drawer on mobile, a top bar and the page content.

Storybook: Storybook
Source: Source

28 October 2026

Added

AppShell, NavGroup and NavItem: a skip link, a sidebar that narrows to icons and a menu drawer on mobile with Base UI Dialog.
A sliding indicator that follows the current page, foldable groups and reduced motion support.
Glass material: under a glass Provider this surface turns glass; material="solid" keeps it solid.
shortcut (default true): turns off the Ctrl+B / Cmd+B shortcut.

Changed

New variant="inset": from 1024 px the top bar and content sit on the sidebar fill as a raised, rounded panel.
Focus shows as a 2 px focus outline drawn inside the item (focus-outline-inset).
The shell no longer writes the bigbang_sidebar_collapsed cookie and APP_SHELL_COOKIE is no longer exported; the app stores the state through onCollapsedChange. The shortcut does nothing in text fields, selects and editable content.