Hypertext Markup Language (HTML) is the standard markup language for creating web pages and web applications, and Cascading Style Sheets (CSS) is a style sheet language used to affect the presentation of a document written in a markup language. Together they are the foundational languages for how browsers display web pages. Most people who build websites through code, or with a content management system like Drupal, should be familiar with the basics of HTML and CSS since these are the main languages of web sites.
- Create a basic web page with HTML
- Style HTML with CSS to change its default appearance
This is a non-Drupal topic and is the foundation of web development, so the resources available are widespread and generally kept up-to-date.
- HTML Spec
- The Living Standard for HTML. All other resources will be using this as a reference, so it's a great idea to refer to it often and use other resources for further explanations, examples, and ideas on how to go about learning HTML.
- Learn HTML & CSS (codecademy.com)
- A great way to learn the basics using their built-in code editor so you can practice directly in the site.
- HTMLDog (htmldog.com)
- Learn Sass (codecademy.com)
- Another Codecademy course that teaches what a CSS Prepocessor is and how to use one of the most popular ones, Sass.
- Front-end web developer guide (developer.mozilla.com)
- This is MDN's learning pathway for front-end developers.
- HTML: HyperText Markup Language (developer.mozilla.org)
- This MDN page lists a number of different resources for learning various aspects of HTML.
- CSS: Cascading Style Sheets (developer.mozilla.org)
- A landing page for various MDN resources for learning CSS.
- Structuring the web with HTML (developer.mozilla.org)
- MDN's guide for newcomers to HTML.
- Learn to style HTML using CSS (developer.mozilla.org)
- MDN's guide for newcomers to CSS.
- Web Platform Docs (webplatform.github.io)
- This has great documentation on the HTML and CSS specifications, how different browsers meet those specifications today, and what the future looks like. It's also a collaboration between some of the biggest names in technology, including Facebook, Google, Microsoft, Apple, and Mozilla.
- Front-End Developer Handbook 2019 (frontendmasters.com)
- This is a great overall resource for all things on the front-end, not just HTML and CSS. If you want to really learn about the wide world of front-end, this is a great place to explore.