Reset defaults in the Colors panel of Preferences

I’m running Rhino 7 on macOS 11.2.1, and I’m frustrated that I can’t return to defaults after customizing the color settings in the preferences screen, which I could do in Rhino 5 for Mac.

That’s a regression and is now on the pile for fixing:
https://mcneel.myjetbrains.com/youtrack/issue/RH-63349

Thanks