You can use something to edit the .png file and replace certain colors with what you want, but it's going to be tricky. Yea, I have done this, but right now I am using no themeatlas. I like the way that looks -- no borders, but it would be nice to have a themeatlas which keeps the default look, but allows me to replace the colors. I'm pretty sure there's a link on the Downloads page of glass8.eu for the Windows 10 theme atlas.