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. Let’s look at the ways CSS custom properties can improve this for us…
CSS Custom Properties allow us to manage and control both cascade and inheritance in new ways.
Custom Property “Stacks"
Repost from CSS Tricks