Board Thread:General Discussion/@comment-16804948-20140408204016/@comment-1330470-20140408212139

Primarily because Wikia has created and utilizes a custom skin called "Wikia", where Wikipedia uses the default "Vector" skin that comes with Mediawiki.

It is possible to switch to a monobook skin which does more resemble Wikipedia's skin (in fact, it is the skin that Wikipedia used to use). Here's what Monobook looks like.