You're using CSS. That's the point. Many people still think CSS is still stuck in 2003. It's still limited, but it's come a long way... Heck, with just CSS you can have a webpage react to your turning off the lights on your phone.
Sure... but it's specifically using CSS to add extra elements. So it makes the "just one div" thing feel a little silly. Surely you could do "just no divs" and do the same trick on the <body> tag?