Full height & width, fixed header, full content height with CSS

I have been searching for this on SO, but I just could not find something exactly similar. What I am trying to achieve is to have a page, that is full in height and in width, but does have a fixed header. The content height needs to be the remaining area left, but that area needs to have a height of 100%, most of the html code found on SO is just using height: auto. Basically I want to do this so that I can style it: adding border etc. Here's the code so far:I have been searching for this on SO, but I jus