[ request ] Make Compatible for Thunderbird  #1059

want to use FFColor in Thunderbird. Unfortunately not available.
I've tried install manually on Thunderbird but not working fully functional
Maybe we'll get a little update for the following features

Option, for inactive toolbar color matching with title bar.
Option, Toolbar bottom seperator color
Option, Sidebar & Mail-List background color

SS Active Window:

SS Inactive Windows: Toolbar and titlebar color not matching