Valid XHTML 1.1 and CSS But it is not displayed right.

Hey gang!

I hope everything is going great.

I have a question about CSS and  @media

www.abyss.ws the CSS hides the navigation menus (left and right sides of the page)

but the same basic style sheet for this page http://www.abyss.ws/temp/
has almost the same CSS code (the only difference is that in the second one i use a class instead of the id reference)

when I go to print preview, the menus are still displayed, and I cannot figure out why.

the css can be found @ http://www.abyss.ws/temp/sea.txt


Thanks heaps
Abyss
Sydney Australia