How would you do this

I am not sure if this even goes here but please feel free to move this post.

I am planning on using the 2012 theme for this and it will be a fixed width and height site. (I know I know, just let it go)

The design is very simple, but I am not sure how I would go about creating this double border with the slight roof pitch at the top and bottom. It is easy enough to make the double border by adding a child theme and adding another div to the outside of the id=page div but the roof pitch is throwing me. Do I need to create a background image for the header and footer and run borders on the content area or is there some way to do this all with css?

here is the link to the design:
http://dl.dropbox.com/u/18576442/clarify/2014-06-12-19h02m/index.html

Many thanks,
Houston