Board Thread:Support Requests - Getting Technical/@comment-37896109-20181222210050/@comment-9605025-20181222213404

With a whole lot of tinkering, you might be able to get close. There is already something called PseudoMonobook that you can use if that is close enough for you. Unfortunately, the actual skin that Wikipedia uses has been removed from Wikia's servers due to a combination of maintainance a regulatory issues. - Edit:

Actually, it looks like this is for personal use only. So you can't apply it to the whole wiki like you want.