I know this is a sort of a common problem, and I looked up some solutions, but couldn't find exactly what I was looking for.
I would like to convert this to a tableless layout.
Note: header and footer have to be set to a fixed height in pixels (50px is ok).
The main problem I'm having is that I cannot get that "big box" in the middle to behave like it does when it's done with tables. There are solutions which work OK for a variable length content (text, images), but I would like this box look and behave like a box – with borders, rounded corners and all.