Board Thread:Support Requests - Getting Technical/@comment-26616407-20151031162437/@comment-1251315-20151031174502

You can't really use CSS to add stuff, CSS only refers to styling existing elements and can't therefore be used to add stuff that doesn't exist.

You need to use JS to do this: if you don't already have custom community JS enabled on your wiki, send a request to Wikia at Special:Contact/general to request that the review tool be enabled for your wiki.