Dependencies in CSS can be a bit more abstract. Robin just wrote in our newsletter how the styling from certain classes (e.g. position: absolute) can depend on the styling from other classes (e.g. position: relative) and how that can be — at best — obtuse sometimes.
Design has dependencies too, especially in design systems. Nathan Curtis:
You release icon first, and then other components that depend on it later. Then, icon adds minor features or suffers a breaking change. If you update icon, you can’t stop there. You must ripple that change through all of icon’s dependent in the library too.
“If we upgrade and break a component, we have to go through and fix all the dependent components.” — Jony Cheung, Software Engineering Manager, Atlassian’s Atlaskit
The biggest changes happen with the smallest components.