Board Thread:Support Requests - Designing Your Wikia/@comment-5454372-20140709192949/@comment-856287-20140710002201

Take a look at w:c:iynque:MediaWiki:Wikia.css at the bottom where multi-column layouts are defined. Using the @media rules, you can define styles that change based on screen size. In this case, two- and three-column layouts are collapsing down as the screen gets smaller. You can see it in action on w:c:iynque (three columns) and w:c:iynque:User:Iynque/Sandbox (two columns). Of course, you can define whatever styles you want. For example, when the screen is wide enough, place certain elements on the right, and when it gets smaller, remove them (display:none).

As far as what happens on mobile, that is harder to control. I have not yet found a reliable way to get any custom CSS (or JS) to load when using the mobile skin (and I think Wikia likes it that way). For example, I want to use CSS to hide elements like RSS tags that don't work on mobile, but I can only sometimes get the CSS to load :(

Until I (or anyone else) can get CSS to load on mobile, you should pretty much just forget about styling mobile and build designs that degrade gracefully when the styles are stripped. ...which you should be doing anyway ;)