The authors of the page made it unusable in my case. There was no way to scroll the page down to read the actual article. There’s no scroll bar, so I couldn’t use my mouse (that does not have a scroll wheel), and the keyboard doesn’t work in Firefox or Safari (but does in Chrome). I’m having flashbacks to the late 90s/early 2000s with “This site works best in … “ nonsense.
It’s annoying, but you have to put your cursor on the article and not the margin.
Totally agree they made a bad choice in implementing this anti-web page. That said, cursor keys do work for me on Firefox.
One of the better attempts at explaining what monads are, actually, really, in essence, that I’ve seen, by way of fairly easy-to-understand concepts from abstract algebra (rather than jumping straight into category theory). And I especially enjoyed the historical background.