Since the inception of CSS in 1994, the cascade and inheritance have defined
how we design on the web. Both are powerful features, but as authors we’ve had
very little control over how they interact. Selector specificity and source
order provide some minimal “layering” control, without a lot of nuance — and
inheritance requires an unbroken lineage. Now, CSS Custom Properties allow
us to manage and control both cascade and inheritance in newways.