Where can I find a simple how-to tutorial for HTML codes?

try this site: http://www.myhtmltutorials.com/

or the HTML for Dummies book is excellent: http://www.amazon.com/HTML-XHTML-CSS-Dummies-Tittel/dp/047023847X/ref=sr_1_1?ie=UTF8&s=books&qid=1236604022&sr=1-1

I learned HTML and C++ from the Dummies series.

http://www.w3schools.com/html/default.asp

This is the link to the w3schools CSS guide…
http://www.w3schools.com/css/default.asp

Thanks, @blastfamy, I didn’t notice the CSS part of the question in the details.

@tammie900, please be aware that HTML and CSS are two completely different languages. Knowing one does not at all imply knowledge of the other. HTML is used for the structure and content of the website. CSS is used for the layout, look, and style of the website.

Have you read this document? http://www.tumblr.com/docs/custom_themes

Ditto on the http://www.w3schools.com/ its an excellent source for both html and CSS.