Set body background

Set body background

Forgive my ignorance, I'm just learning jquery...
I have my pages set up using sortables, I have themes working.
I'm also using the ui layout plugin (<a href="http://layout.jquery-dev.net">http://layout.jquery-dev.net</a>)
How do I set the body background to switch and use the theme background settings?
I've looked through the docs/google but I'm probably just stupid :-)
So I have something like this:
<div class="ui-layout-center">
<!-- Start Column 1 -->
  <div class="column">
    <div class="portlet"><br clear="all">
How do I set the background of the whole layout to match that of the theme?
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Clayton Dukes
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