From what I can tell, something's messed up with the text color when a toolbar button is checked on google docs. For one, the color code is invalid; #FFFFFF80 isn't a color. It defaults to #929292, which isn't too bad as a highlight color tbh.
The issue comes in with the text color. It's this really odd pink shade that makes it a bit difficult to read against the gray background selected. Strangely enough, I can't find anything within your style whatsoever that prompts it to make it this color [#d27fb9], and my feeble attempts to change it have been met with no results- it just remains pink entirely.
There's a link to some screenshots with what I'm talking about below. The text color should be changed to something a bit more neutral, or at least something that contrasts better. Right now, on a full screen, it just looks illegible.
Edit: Sorry for so many posts, kept getting an error when trying to send and presumed it wasn't going through >.<