Q&A plugin wrecks havoc on my theme

Hi, I’ve installed Q&A and on the questions/ask page the styling has gone all whack.

http://184.172.185.14/~xpand201/questions/ask/

I’ve added some css to get the wrappers background white:

#qa-page-wrapper {

background: none repeat scroll 0 0 #FFFFFF;

float: left;

padding: 120px 0 0;

}

But as you can see it has made the rest of the page grey in background which is very weird.

Thanks for your help.

Ellissa