I don't know if this is the right place to post this question. Using OpenSuse Leap 42.1. I'm trying to change the window borders from dark black to something more attractive. Using Thunderbird, for example, works fine, but the top border is dark black, and I'm looking for something less stark. I've looked in the System Settings>Themes>Window Borders, but there is no option available other than numix, which is really ugly. Is there a way to fix this? Thanks.