need some help with CSS for a footer

I am trying to achieve a footer (using global headers plugin) on all blogs.
here is the current look: http://zice.ro/next.php (this link will server you one random blog so you can check it with different themes)
the current CSS code uses position:absolute and that is ok, except that if a blog has no entries yet the footer won't stick to the bottom of the viewport but to the actual position of the footer thus making it be positioned somewhere in the middle of the screen.

I thought about using min-height but I would have to globally apply that to the body element. not sure if this is the way to go?

anyone can help me out here? remember the link above I gave will send you to a random blog so you can test out different themes...

###edit###
here is an example that looks crappy: http://conservator.zice.ro/