User blog comment:BertH/Darwin - The Next Evolution of Wikia/@comment-3545644-20130822173144/@comment-11733175-20130822175842

Special:CSS isn't available in monobook and the fluid layout only applies to Oasis. I can't say if anything in the later stages will affect Monobook, but as for the current publically released changes there shouldn't be anything that alter Monobook.