The starter is mobile friendly out of the box, so the layouts, navigation, and menus all work on a small screen without a separate mobile build. The one piece worth calling out is how off-canvas navigation is handled, since that is where most of the mobile-specific work lives.
Off-canvas menus are built on a SheetMenu composite that wraps the shadcn sheet primitive. It takes a side, left or right, a width, and a header height, and gives you a slide-out panel with a logo header, a scrollable body, an optional footer slot, and a close button already wired up. App-level menus like the account and notifications panels are thin features built on top of it rather than each rebuilding the same shell.
Two conveniences are baked in. The panel closes itself when you click a link inside it, so anchor navigation does not leave a menu hanging open, and the accessible name is handled through a visually hidden title so screen readers announce the menu without you thinking about it per instance.
Component Architecture for why SheetMenu is a composite over the sheet primitive rather than an edit to the primitive itself. Layouts for how the menus slot into the wider layout.