selected sidebar item style
The gray used for the selected item in the demo looks quite odd, I think primarily because the gray is too dark and the text inverted. The inverted look works for blue, but for gray a more subtle non-inverted style would make more sense. We've been doing something like that in Nautilus for a while, and I think we should just the same thing everywhere.
Nautilus for reference:
cc @jimmac
Edited by Tobias Bernard