RPi Projects has tutorials to teach the languages of the web with funny projects like a meme generator, pixel art, an internet cookbook, and a zombie survival map!
Other Intro Tutorials
Khan Academy (HTML/CSS)
Hacking the code of an existing website can be a fun way to dig into web design!
Built a website you're ready to publish? Here's how to do it for free from Google Drive, using a tool called fast.io:
If you want to start from a blank slate and build your own web page, codepen or Glitch are great toosl. Need hints or refreshers? Check out W3Schools.