Its a giude about web UI best practices, and the icons symbolizing the different topics are not clickable?

Besides, I didn't even notice that some of the headlines/h2s in the subsequent pages are actually clickable.

Then, they actually enlosed their <video> elements inside a <a> tag. So now, when I click on the controls of a video, it will open the linked page. No way to use the video's controls without leaving the page I am reading.

Three basic errors found in under a minute on a simple text site. I don't think I want to take any UI design advice from that person.