Looks different in Firefox and Safari

I’m trying to make my header look the same in both Safari and Firefox, but if your check it out, you see that there is a lot more air underneath the header in Safari than in Firefox. When trying to make the distance smaller, the header comes behind the infotext in Firefox.

I’ve tried using Firebug, finding out what the problem is, but I have no idea.

Please help?

You can see my website here.