Helpp messed something up :(

Hey,

I need some help with the next website: http://www.rbg-assurantien.eu

The full screen is fine but once i set the width to arround 1200 or less it gets a lil scroll bar on the bottom and u can scroll to the right and thats a empty blank space. Can any 1 tell me what i have done wrong? I cant find it in the css 🙁

Cheers