The text on the linked page is really light (depending on your installed fonts). For anyone who wants to make it more readable, it’s super-easy. Just right-click on one of the paragraphs, “inspect element”, look in the right hand pane that gives the CSS properties for “body”, and deselect font-weight:300.
One can imagine a world where web designers understood typography, respected the reader and the font designer, and did not break readability for style. But that world is not this world. </rant>