CSS inherited tokens and units
Local custom-property overrides, invalid substitutions and font-relative lengths.
Override one inherited token locally
Trace a green token into a purple subtree while outside siblings stay green.
See when var fallback cannot rescue a token
Distinguish a missing custom property from a present token invalid for width.
Avoid accidental font growth in nested content
Compare two nested 1.25em sizes with two nested 1.25rem sizes.