I am looking at a website on the internet with the standard centered box design (the entire site is centered in a box and has a border each side). As you shrink it, the border gets smaller but the content stays the same size. This is fine.

However on their site, once you get smaller still, you simply get scrollbars. The content remains untouched. On my site if you do this, things like text and links start to scroll onto multiple lines and the whole site gets broken. How can I keep it the same even when the viewport is small?