[puppybeard]

Mozilla Developer Network already is the replacement for W3Schools. Even for experts, it's a great reference.

https://developer.mozilla.org/

You'd have to be very green to find w3schools to be any use, and even still, it would you bad advice too often.

Speaking as someone who develops html and css professionally (among other things), no they aren't programming languages. To call them as such would suggest some sort of logic, which unfortunately isn't present.

It takes maybe two years using them professionally most of your working days to become an expert. Everything after that is monotonous, repetetive drudgery.

Html5 is a disorganised mess and the wonderful css3 is vendor-prefix hell. I know a lot more of both of these languages than a sane person would want to, and I need a new job. The DOM is a handicap. The front-end of the web is broken.