This is actually part of the design of CSS custom properties. It's not an abuse, but part of how they've been designed to be used. You can trigger updates from

This is actually part of the design of CSS custom properties. It's not an abuse, but part of how they've been designed to be used. You can trigger updates from your own code programmatically, as well as any event listeners (built-in or custom) or from Observers the browser may have (e.g. Resize Observer, Intersection Observer, Mutation Observer) or any other ways you want to update them!