Kevin Sweeney 15 December 2009 I agree with steffenbew and sam. CSS transitions affect how elements behave, not how they are styled. I think you do make an interesting point Drew, but it can be argued that the behavior of a spinner is that it is perpetually rotating. Not an exciting behavior, though behavior nonetheless. As to the argument for rollovers, I think it’s better to view the pseudo-classes like :hover and :active as states rather than interactions or behaviors. Here, animations are being defined within those states, so they’re really two different things.