This causes the blank white screen problem. The page is totally blank until the stylesheet at the bottom is downloaded, on the order of 6-10 seconds for this page. The browser is waiting for the stylesheet to be loaded before it renders anything else in the page, even the static text.

This is a valid syntax, but, even though it’s in the document’s HEAD, it breaks progressive rendering and instead causes the blank white screen and Flash of Unstyled Content problems.