Update 02-the-basics.md

random comment: <br> can also be written as <br />, yeah, which kind of is a tag that closes itself, eh?

updated img example to be a bit more helpful

"The `img` element is also a self-closing tag, meaning it has a forward-slash before the closing angle bracket." possibly explain what it means to "close" a tag at all, for absolute beginners in html?

or maybe you're assuming people already know basic html/coding. that's okay, too.

* surprised you didn't include W3Schools in your html/css resource list

Variables: you go from talking about html + css to Variables. is the reader to assume that you're talking about javascript now/again? there's absolutely no transition here and to me as a reader, the sudden subject change (without any transition/new chapter/etc) very jarring and I'm confused.