Here are some useful sites for learning about HTML, CSS, and related subjects:
- Mozilla Thimble — learn from scratch, or use their projects to understand and use HTML and CSS code.
- w3schools.com – tutorials and reference material for many web technologies.
- A video on YouTube – also has links to additional resources on this page.
- The Code Player – an assortment of tutorials disguised as fun projects to learn HTML5 and CSS3, displayed Pinterest-style.