One of the most valuable resources on (and about) the web is developer.mozilla.org. Whether you’re looking for tutorials or detailed reference manuals for specific aspects of HTML, CSS, SVG, and JavaScript, this canonical source should be your first stop.
An additional consideration with any web API is how broadly supported it is on the browsers that are currently in use. Whenever you’re worried that a feature you want to use might be too bleeding-edge to risk, try searching for it at caniuse.com. It’s the best way to see which browsers have implemented a given feature and what proportion of the browsing public is likely to be able to take advantage of it.
These two sites have a wealth of knowledge and articles across the spectrum of front-end web development.
While I wouldn’t recommend signing up for each of these (information overload 🙀) consider adding 2 to your email inbox. I find email newsletters to be a nice, bite-size way to keep learning about web development.