Div height issue
===

I'm having an issue with height of a `div` element in my code.

Take a look at this example: http://jsfiddle.net/qUfr8/ <br />
...and now this: http://jsfiddle.net/DdUbr/

Pay attention on the red border. It's fine in the first example, but not in the second.<br />
The only difference between those examples is that I added two `div` elements to the second code and now the height of `content` is equal to 0, but the `content` is still displayed, though.

How I can fix this issue?