git web interface version 1.7.12 (though it may work in older versions, too …)
Just copy the CSS-file gitweb.css into the gitweb folder. Best practise is to rename the old file, in case you want to switch back.
Stefan Imhoff (stefan@imhoff.name)
You can download this project in either zip or tar formats.
You can also clone the project with Git by running:
$ git clone git://github.com/kogakure/gitweb-theme