I made the Live 9 Default skin a bit darker for using at night because I'm not a fan of Disco.
Put the file into Live's skin folder.
-PC: C:/ProgramData/Ableton/Live 9/Resources/Skins
-Mac: Applications/Live 9 (cntrl-click)/Show Package Contents/App-Resources/Skins
After doing that, go to Preferences and change the skin!