This seems like a really interesting page, unfortunately it's currently hard to consume on a smartphone: no mobile view and not possible to enable Reader Mode even on Firefox for Android :(
To be fair, a big part of this page is the interactive exercises, which would be a nightmare to try to do on mobile anyway. So I can see why being compatible with mobile wasn't a big concern.
Well reading about this non interactively is still better than, well, not reading at all. I have vivid imagination!