Board Thread:Support Requests - Designing Your Wiki/@comment-33281220-20171008085630/@comment-9605025-20171008111855

That wiki-style forum was from 2012. There have been many changes since then. If there is a particular sans-serif font you want to use, I can help you with that. However, as I already stated, the default font is already a sans-serif type.

The difference between the two is related to the skins they affect. In short, a skin is a general style along which the page is rendered (displayed). For "new" (post July 2014) wikis, Common.css impacts both the default skin (currently something called Oasis) and a skin called MonoBook. Meanwhile, Wikia.css impacts only the default skin. You can switch which one is used for your account by going to "My Preferences > My Info > Appearance > Layout". There is also a third common skin, Mercury, which is used for mobile devices. How content is displayed depends on which skin is used. If you want to temporarily view a page using a different skin, you can add the skin to the query string of the URL. For example:

Help:Community CSS and JS

[ using Oasis]

[ using MonoBook]

[ using Mercury]