JS is a good place to go next! You'll be able to use it almost immediately with the HTML/CSS knowledge you have, and, in addition, you'll be able to start doing back-end stuff on Node. If possible, get going with TypeScript -- there's a little extra overhead, but it will (a) help you to make fewer mistakes and (b) set you up for Angular or React (and you can use it effectively with Vue too, and on the backend!)
JS is a good place to go next! You'll be able to use it almost immediately with the HTML/CSS knowledge you have, and, in addition, you'll be able to start doing back-end stuff on Node. If possible, get going with TypeScript -- there's a little extra overhead, but it will (a) help you to make fewer mistakes and (b) set you up for Angular or React (and you can use it effectively with Vue too, and on the backend!)
Just dropping into add that you can solve FizzBuzz with just HTML and CSS.