Only --radius-md (8px) is a sourced example from vois-tokens; the rest of this scale is invented for the kit to fill a documented gap. The concentric math rule below is sourced and load-bearing — keep it even if you retune the scale.
outer radius = inner radius + padding. A 16px outer radius (--radius-2xl) with 8px padding (--space-8) nests an 8px inner radius (--radius-lg) — not a matching 16px, which would look loose.