While we're on the topic of default colour changes, you will find that all your default colour buttons have changed from almost white to blue, and page backgrounds have changed from a nice, minimal eye-strain EEECE8, to a bright, eye-straining, almost white :/. I actually don't mind the black change as I try not to use full black anywhere anyway. The new page colour though is horrendous and I go through and change this EVERYwhere. It affects containers as well. Very annoying...
Also, might be useful: