Ifyousetyourwebsiteto "float," positionedinthe middle of thebrowserwindow with space on either side, then you canset your headerwidth to whatever you want.
To Henry Cao, who was seated beside a windowin the last compartment of the second car, the train seemed to float, describing long elegant turns and shuddering now and then with the whump of a train going in the opposite direction.
Goux at his window, watching clouds float through the sky over Paris and comparing them unfavorably with certain clouds in paintings by Pissarro or the clouds in his nightmare.