The layer the surrounding container is rendered in, e.g. to behave differently when placed inside an overlay.
The visual nesting depth of the surrounding container, where 0 is the
top level and the number increases with nesting.
Prefer ContainerAppearance to match the look of the surroundings.
Only reach for level when a rule genuinely depends on the nesting depth
itself (e.g. a customer style guide that overrides a value at a specific
depth) — keying behavior on it makes your element depend on where it is
placed.
The resolved visual appearance of the surrounding container. Use this to make your element blend in with its surroundings.