Here are some resources that might be helpful:
http://learn.wordpress.com/
- basic guide for WordPress beginners
http://en.support.wordpress.com/custom-design/css-basics/
- guide to basic CSS customization using the CSS upgrade, but some techniques can still be used with "inline" CSS as I showed you above, even without the upgrade
More resources:
http://htmldog.com/
http://www.w3schools.com/
http://www.wpyogi.com/
Good luck!