Refresh Button Widget and Theming

A while back, marvin.kickuth wrote “Currently it isn’t possible to directly style the refresh button, though it is likely be possible via WebPortal theming. I’ll ask internally; maybe I am missing something.”

To follow up on his internal ask: Is it possible to (oh let’s say) change the yellow color or background-color of the Refresh Button Widget with Theming? My workflow’s background color is set and introducing the Refresh Button Widget introduces all sorts of white and colors that don’t belong. Will theming address these problems?