HTML Summary
HTML (HyperText Markup Language) is used to define our page content, structure and meaning.
You don't use it for styling purposes. Use CSS for that instead
HTML uses "elements" describe (annotate) content
HTML elements typically have an opening tag, content and then a closing tag
You can also have void(empty) elements like images
You can also configure elements with attributes
There's a long list of availabe elements but you'll gain experience over time, no worries.
Learn more about all available HTML elements on the MDN HTML element reference.
CSS Summary
CSS (Cascading Style Sheets) is used for styling your page content.
Styles are assigned via property-value pairs
You can assign styles via the "style" attribute
To avoid code duplication, you typically use global styles (e.g. via the "style" element) instead
Alternatively, you can work with external stylesheet files which you "link" to
Whn working with CSS, concepts like "inheritance","specificity" and the "box model" should be understood.
Learn more about all available CSS properties and values on the MDN CSS property reference.