Styling options for actions or buttons are very limited.
In general, more styling options to control buttons/actions/hotspots are welcome.
Simulating css hover effect on an action is almost impossible now. The only thing you can do is to set Display border to 'on mouse over'.
One option is to be able to set an alternate background image for 'on mouse over'.
The border for an action hotspot is a fixed color. Allow designers to set alternate colors and/or hover effect on an action.