Fixed width forum
 

Hi,

I need to create a fixed width forum of 900px so I can wrap some styling around it. The styling involves setting a 900px by 4px image in repeat-x behind the forum. I've tried and failed to get this consistently working, I keep finding sections of the forum which don't have it displaying and where parts of the theme are bigger than 900px.

Surely there must be a single thing to change to achieve this rather than lots of things?

Any help is greatly appreciated, I'm using 3.8.4

Cheers

Mike