You have done a good work on the skin.
However, I find it lacks an accompaning license. The terms at
also make it more
confusing, as it seems to be unfree. Still, as you're linking against
MediaWiki (and even derivating code from it), it should be GPL. You can
still sell or provide it for free to whoever you want, but the lack of
GPL notice on the copies is in itself a GPL violation.