1. 1. CSS
2. 2. CSS intro
3. 1. 2.1. What is CSS for?
   2. 2.2. How to add CSS to an HTML document?
   3. 2.3. Inline style attribute
   4. 2.4. In the head or body of the HTML
   5. 2.5. External stylesheet included with a link
   6. 2.6. background
   7. 2.7. Learn layout
   8. 2.8. No layout
   9. 2.9. margin: auto
   10. 2.10. box-sizing
   11. 2.11. display
   12. 2.12. position
   13. 2.13. boxes using div
   14. 2.14. Resources
   15. 2.15. modal