Setting Page Width

[jasonbrice]

Hi,

 

This seems like a dumb question, but:

 

How do you set the width of pages globally? I can't see a veriable for it any where.

 

I'm trying to get the body of the page the same width as the header:

http://www.arcanastudio.com/store/

 

Any help is appreciated!

 

Thanks!

JB