Why is all the content squashed into the middle of the page when I view on a laptop? Am I supposed to think it looks good like that or is it designed for a phon

Why is all the content squashed into the middle of the page when I view on a laptop? Am I supposed to think it looks good like that or is it designed for a phone/tablet? Shouldn't the site be showcasing technology that allows pages to look good on desktop and mobile? (Honest, and probably stupid question -- I would like to understand.) e.g. http://www.csszengarden.com/?cssfile=/211/211.css http://www.csszengarden.com/?cssfile=/211/211.css