> Conceptually you could think of these as classical inheritance (so class Card extends Div) - inherit the semantics and base styles of div while making a re-us

> Conceptually you could think of these as classical inheritance (so class Card extends Div) - inherit the semantics and base styles of div while making a re-usable style for a Card class. You could, but you’d be wrong. The CSS selector specificity algorithm has nothing in common with OO inheritance, and classes are only one of many equivalent ways to interact with that algorithm.