Let's solve that by switching to a different abstraction that proves to be more useful. In this case, isolation-by-component instead of isolation-by-class.

I'm not the person you're replying to, but I'm in a similar position, and while I'm not in love with Tailwind*, it's successful because it's oriented around components rather than classes. In every project I've worked on, it has been far easier to manage the complexity of components over classes, because components link style and structure together, which usually end up very tightly coupled anyway. This limits the scope of the CSS you're writing a lot, making it a lot simpler to understand what any individual declaration is going to do - you know exactly where it's being used, you know exactly the HTML structure it's operating on, you can see exactly what it will do as a result.

* I use it a lot at work because it's very easy to get something written, but I find the pseudo-CSS DSL irritating if I need to write more complex queries. Something like CSS modules requires a bit more boilerplate to use, but you end up writing real CSS queries, which I find more natural. But this is personal preference.

Let's not spend extra effort supporting a theoretical feature that won't actually happen.

It happens pretty often. I change the style of my websites this way all the time.

Ok, sure. But that's not what you were saying in the comment I responded to.

Because you moved the goalposts. First you said that it “almost never” happens, then that it “won't actually happen”.

Its hard keeping track of different usernames on here.

From my perspective, "almost never" and "won't actually happen" aren't that different. Both indicate that the probability of success is very low. It seems to be, if the probability is already really low, is not worth extending effort maintaining it.

They never said that. I did. You're talking to different people.

Oh, sorry. I'm not looking at usernames.