That document does not itself follow their own advice (perhaps due to being part of another web site with their own CSS stuff), although a few web pages do, The example they give, like below (although I entered different text), is good way to make a web page, although a rather simple one. It is also rather readable even if you do not have a web browser (or won't open it just to view one document).
<!DOCTYPE html>
<html lang="en">
<body>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do
eiusmod tempor incididunt ut labore et dolore magna aliqua.</p>
</body>
</html>
"You can build a robust, reliable, and fully responsive web application today using only semantic HTML on the front-end. No images. No CSS. No JavaScript. It’s entirely possible. It will work in every modern browser. It will be straightforward to maintain. It may not fit the standard definition of beauty as far as web experiences go, but it will work. In many cases, it will be more usable and accessible than those built with modern front-end frameworks." I agree with this. But, they say it is not the best approach; well, sometimes it is, I think (not always, but perhaps usually, especially for documents which are not "apps"). It is much more usable and accessible, and I also think it actually does look better too (especially considering, if the user configured their browser with the fonts and colours they want it, then the user will be satisfied, I think).
