I don’t know if MDN for learning web development is yours but if it is you should fix the nav. Everytime ı try to learn some JS I can’t because of your navigation. It changes whenever I click on a link. That makes staying there impossible because you don’t know where you are right now and what to learn next. I didn’t know how to give feedback to them so decided to join their developer community. Hopefully it is the right place to give feedback about MDN mozilla for learning the web technologies.
You could make the nav easier to use like
- w3schools or
- javascript.info