Sidebar
A collapsible navigation panel. On desktop it collapses to an icon rail; on mobile it becomes a full overlay drawer. Collapsed state persists in localStorage. Compose with SidebarGroup, SidebarItem, SidebarHeader, and SidebarFooter.
Collapsible sidebar
Click the hamburger trigger to collapse to an icon rail. Labels fade out, icons remain. Resize to mobile (<768 px) to see the overlay drawer instead. Collapsed state persists in localStorage.