Colour carries depth; shadows are the exception
Standard containers never carry a shadow. Depth comes from stepping through the container colour ramp, which keeps surfaces flat, crisp, and legible against the page floor. Only surfaces that genuinely float above the page (anchored overlays and modals) earn a shadow, and there are exactly two tokens for that. Never write a literal box-shadow value in component CSS.
Shadow tokens
Both tokens are defined per theme, with stronger opacity in dark mode so they still read against the #050505 floor.
Depth without shadows
Everything below the floating layer expresses hierarchy through background steps. A nested surface reads as deeper because it is a shade further along the ramp, not because it is lifted.
The one exception
Interactive Card and EntityCard navigation tiles lift on hover. That shadow is a deliberate navigational affordance, a signal that the whole tile is clickable, not an elevation pattern to copy onto static containers.