In IE8, you lose the shadows and the bubble tips become all robot-y (because IE doesn’t support CSS3’s
transform property at all):
Finally in IE7 you lose the tips altogether:
If this graceful degradation is acceptable to you, i.e. whoever wrote your brief understands IE is already going the way of the dodo, here’s the SCSS I built.
It comes with variables o easily adjust it to your use case.
You can play with it in this JSFiddle. Enjoy!