Please don't write off somebody's lack of attention to typography as a virtue and clever design. It's not. Browsers display it how they are told to display it. Maybe your system could use better fonts or line spacing by default, it's arguable, but it definitely would be stupid and unreasonable for browser to enforce less than maximal width for some of your div's if not told otherwise. If anything, they already enforce more than they should (that's why normalize.css exists).
And, by the way, it's not like there's no css at all in the source. It's just UX-ignorant, so to say.
And, by the way, it's not like there's no css at all in the source. It's just UX-ignorant, so to say.