Why isn't CSS being recognized?

I have added the CSS outlined here http://catablog.illproductions.com/2012/02/multiple-column-tutorial/ to my theme’s CSS but nothing has changed. The theme is Atahualpa. Both it and Catablog are up-to-date. This is the site:

http://www.kimspersonalizing.com/?page_id=2

What am I missing? Thanks for your help!!!

http://ww.wp.xz.cn/extend/plugins/catablog/