Ian, the problem is that CSS is a constraint description language, not an imperative language. So there is no "before" or "after"; there's just a state...
On the one hand this means that as things change it updates dynamically and all.
On the other it means that you can't just base queries on some "before" state. :(
I think we all agree that there are use cases that need solving here, for sure. We just need to figure out how to do it... Ideally while not precluding parallelized evaluation of CSS selector matching, style computation, and layout, which doesn't make things any easier.
On the one hand this means that as things change it updates dynamically and all.
On the other it means that you can't just base queries on some "before" state. :(
I think we all agree that there are use cases that need solving here, for sure. We just need to figure out how to do it... Ideally while not precluding parallelized evaluation of CSS selector matching, style computation, and layout, which doesn't make things any easier.