Before getting into that, we should agree that what is meant by “learning HTML and CSS”, because the answer to this question changes based on your needs.
For example, if you are a web designer who just needs to add some subtle styling to a website, then you don’t really need an in-depth knowledge of CSS so much as knowing where to look up what you want when using Google or another online resource.
On the other hand, if you’re tasked with building a client’s website from scratch, then it would be wise for you to learn more about the nuts and bolts of HTML and CSS.
What should I learn first HTML or CSS?
If you’re serious about web development, don’t learn by playing with the interface. A lot of tutorials are written that way, but it doesn’t lead to success because you miss out on fundamentals. HTML is the foundation of every website so, without knowing it well enough, you can’t build anything useful.