css - Help theming media wiki -

I have installed the media wiki as part of my website. How do I make media media wiki so my site looks like? The guide shows a common.css. Where is this file? How do I go about editing it? Can not I just use my site css file rite?

Here you are talking about MediaWiki skins Here is one

P> How do I not give you a hurry (Even not possible) - Your best bet is to just read these links.