How hard is it to create a style?

I would like to ultimately have my forums completely skinned to match my site, but since my site is not finished, that doesnt matter at the moment.

As far as creating a new style though, how hard is it? and can I create one without affecting what my users see until it is done? I have gotten a couple offers to create new skins for my site, but before paying the money, I would like to know just how hard it is to do on my own.

If you want a high end graphics "SKIN", it's not easy IMO. If you want a great "Style", spend two days playing with a copy, a child copy, of the default skin and make it yourself.

Not very hard. This forum uses a 'style' so to speak. Not a skin. Skins add alot of html and real intensive ones can make your pages lower to load.