Website pushed to right in firefox

You might want to fix some of these:
https://validator.w3.org/check?uri=http%3A%2F%2Fwww.dakzoekje.nl%2F

i don’t think that there is the problem, because in IE it’s working fine. I think there’s somethinge wrong in my style.css

edit: I found out what the problem is, i only don’t know how i can fix it.
The problem was that the original theme (Crimson) was 740px, i made it 1000px.. but the left side stays in center and on the right side it’s add the other 260px. So how can i fix this?

Problem solved

My #container was still at 740px, i changed it to 1000px and its okay now