Surface stack
Use the lowest level that communicates the relationship. A card should not look like a modal, and a popover must clear the content it temporarily covers.
Level 1 · Resting surface
Cards and contained previews.
Level 2 · Raised surface
Sticky controls and active panels.
Level 3 · Overlay
Temporary surfaces that need separation from the page.
Tokens
Portals and layers
- Portaled content such as
DropdownMenubelongs above the local stacking context and must keep keyboard focus inside its own interaction. - Reserve the shared high layer for overlays; do not raise ordinary cards until they compete with navigation.
- When a shadow is not enough to distinguish a surface, add a border or backdrop rather than a darker shadow.