Actually, this seems to be an HTML page from the DOCTYPE
Code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
At the top of it is CSS. Can you see the <style type="text/css"> and </style> tags? Everything in between the two is CSS.
Everything else (at least most of it) is HTML. But wait, its not pure HTML, I can see some custom tags in between like <Blogger>, <BlogDateHeader>, etc. And what are those $BlogDescription$, $BlogTitle doing in there?? So it seems like XML but I am not too sure!

DAMN!! There's so much more to learn!!