Paper

Composes with the classes `Box` computes instead of replacing them.

Which scale the `variant` paints with. Does nothing without a `variant`.

The element it paints. `article` or `section` when the sheet is a region of its own, so the elevation does not cost you the semantics.

Elevation. It reads as height, so keep it consistent with what sits around: a sheet raised above its neighbours for no reason reads as an overlay.

The colour recipe, resolved against the theme's `variantMap` — so what `filled` or `glass` looks like is the theme's call, not the component's. Without it the sheet is the plain raised surface, which is the right default for a page.

Draws the edge. A `variant` that already brings its own border turns it on regardless, so this is only needed on the flat sheet.