Just a place for me to keep useful links for myself. You may find them useful to of course.
Once again the top spot here goes to MDN. They have excellent post covering HTML basics here. But as usual with MDN, its thorough and accurate.
Here is a free interactive course with a focus on CSS https://scrimba.com/p/pWvwCg/c3vE7cg
PouchDB / CouchDB