[TYPO3] Strange headlines in Fx

[Andreas Balzer]

Hi!
I have a strange problem in Firefox with my headlines generated by CSS 
Styled Content.

http://andreas-balzer.de/sonstiges/headlines

As you can see in the html file, Firefox displays the headline behind 
the text. Well.. If you look into the html sourcecode, you'll see, that 
normally it should be displayed on top of the text..
How to solve this?

I'm using T3 4.0.2, no TV.

Greetings
Andreas