I have tried all solutions to overwrite the TmtTree class in the termstoremanager.css - to no avail (Can't overwrite that css right?). So I added the class to my core.css to overwrite the default black font color:
.TmtTree {
font-size: 8pt;
margin: auto;
**color: #ffffff!important;**
}
But it's not working at all!
Our theme's background is dark - so termstore is using the default black font - which is not working on the dark background theme.