I’ve said this before: We’re primarily a web shop here at Good Enough, but occasionally we come up with ideas that we think would work really well as a native desktop or mobile application. Still, we prototype those ideas on the web first. Recently, I wanted to try and make one of these web prototypes look and resemble a native Mac app as much as possible. My first inclination was just not to use any CSS at all, but that’s pretty limiting. Then I found CSS System Colors.