Help with Page Background

[Remedey]

Okay, I am trying to put a border on my pages background by adding:

border: 1px solid #000000;
padding: 20px 20px 0px 20px;
to the Page Background Extra CSS Attributes, but when I do this, the posting gets messed up like so:



Those black lines go across.
The main forum page is okay but posting area is messed up.