How do i keep the page the same size relative to the user resolution used. For example when i am creating my page in 1024x768 then the margins are quite far from the edge whereas if i switch to 800x600 then the margins reduce(page is much fatter) ....?

I think it may be my css that's restricting the page from resizing automatically, will this be right? Is it because i am working in px and not percentages?

The first pic is 1024x768 second pic is at 800x600