Themes

System UI appearance is replaceable product presentation.

A theme owns chrome geometry, colors, controls, menus, taskbar treatment and theme-specific icons. App packages, System policy and host protocols remain unchanged.

Theme boundary

Theme changes preserve each application's client rectangle. Window outer geometry is reframed through the selected chrome metrics, including normal, maximized and restore geometry. Pointer hit testing, caret placement and compositor surface placement all consume the same active metrics.

Switching

Open Start → Settings and choose a theme. During development, Cmd + Shift + T toggles the active theme.

Pocket Desktop Classic 98 theme

Classic 98. Hard bevels, compact 18px chrome and a 28px taskbar.

Pocket Desktop XP theme

XP. Three-stop Luna gradients, 21px caption controls, shaped close button and a 30px taskbar.

Rendering contract

Both themes lower to PocketJS DrawList operations. XP's middle gradient stops use the framework's via-* utilities, which lower to existing gradient rectangles and triangles. No theme adds a backend opcode.