Board Thread:Support Requests - Getting Started/@comment-3326238-20150218071430/@comment-1038387-20150218111033

You can set monobook as standard in your preferences, but that only means you see the wiki in Monobook. I'm not sure if they still allow wikis to change to monobook completely (as it's an older, less supported skin), but you can ask at Special:Contact/general.