Not the OP, but what I commonly see are elaborate behaviors by devs to try and avoid dealing with specificity head-on, because it’s so hard to reason about. In my opinion this leads to CSS that is two to three times longer than strictly necessary.

That said, I also believe that CSS was the wrong solution to the wrong job: CSS addresses the DOM, not the UI, and does so with a kind of “multiple inheritance by default” approach, where an element will inherit properties via the cascade from many rules, until a rule that stops the cascade is written. Reasoning about what rules apply to what elements under what conditions becomes an exercise in extreme abstract thinking, and still there is another step to think about what the resulting UI that it will generate will look like. (I’ll leave off browser differences for now.)