Automatic extension of side borders based on page content height
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I'm making a website and have "borders" around my main content. I say "borders" because its not a css border, but div's with a background image. 

Now I have my left and right div borders (#cont-border-left/right) height set explicitly to 675px, and I have another div (#extend-l/r) just under that which I want to expand down the page when the main content goes past 675px. 

I'd like to to this using only CSS if possible, but if not Javascript/JQuery would be a great solution for me as well. 

I was going to paste a bunch of the code here, but it would probably just be easier to view the source, because I think it will make more sense if you can see it all together.

Page here --> http://www.akronmediasolutions.com/gcs

Any ideas on what I should try out?

Thanks!