CSS animations in Twine mirror regular CSS animations. If you want some examples of what and how you can do those, look here.
@greyelf has also posted some examples for dynamic text styles here. The Usage examples have been corrupted in that thread as they have pointed out, so keep that in mind. The correct usage would be:
@@.shadow;This text should have a shadow@@
@@.emboss;This text should be embossed@@
@@.blur;This text should be blurred@@
@@.blurrier;This text should be blurrier@@
@@.smear;This text should be smeared@@
@@.mirror;This text should be mirrored@@
@@.upside-down;This text should be upside-down@@
@@.fade-in-out;This text should fade in and out@@
@@.rumble;This text should be rumbling@@
@@.shudder;This text should be shuddering@@
@@.pulse;This text should pulse once@@