[munk-a]

I think it's fair to acknowledge the clash, but "if" is our word for that thing - "when" could have been that word - every time you do a conditional jump you're only doing it when certain conditions are met "when x > 5 { y += 3; } elsewise { y -= 1; }" that reads perfectly fine - but it's common convention to use "if" for this condition.

I don't really have a strong opinion on the when vs. if fight w.r.t. yielding support to SASS but I think that "if" is just a better keyword to use in this instance based on language usage alone.

[twiss]

I think the difference is that, if x later becomes > 5, y doesn't suddenly get increased by 3.

By contrast, in CSS, if the condition later becomes true, the declarations in it do start to apply. So I also think "when" (in the sense of "whenever") makes more sense than "if".

[munk-a]

CSS is evaluated (probably) in some sort of event loop in the browser - you can also evaluate the code I included above in an event loop - there is nothing inherently instantaneous or continuous about CSS and, given that it is deterministic, it's only actually recalculated on certain event triggers.