Keyframes work, as well. Then you just type SomeStyleName into the style.classes property of your component and you're good to go.
These posts might explain it better than I can.
On another note, I was able to get a tooltip to show up with some static text, but I've been looking for a way to change it within the designer, maybe as a component property. I am learning as I go with CSS, so if anyone has any suggestions I would appreciate it.