Elevation
Depth by tone first, a 1 px border second, a shadow last.
Shadows are the last resort. Each elevation is a named role with one shadow, so floating UI looks the same everywhere and dark mode can soften every shadow in one place.
Elevation roles
elevation.flatThe default. Structure from tone and the border.
elevation.raisedA card that floats over the canvas.
elevation.floatingMenus, popovers, the select list.
elevation.overlayDialogs and sheets.
Radius
Radii of 8 px or less (DECISIONS.md #15). Semantic shapes name what each radius is for.
radius.none0px
radius.xs2px
radius.sm3px
radius.md4px
radius.lg6px
radius.xl8px
radius.full9999px
shape.control4px
shape.container6px
shape.overlay8px
shape.pill9999px