Starting with HTML + CSS teaches how to create a first style sheet. For a quick intro,
try chapter 2 of Lie & Bos or Dave Raggett's intro to CSS. Or
see examples of styling XML and CSS tips & tricks. W3C's Core Styles are simple style
sheets ready for use. Web Standards
Curriculum is a self-study course.
W3Cx is W3C's free MOOC learning platform.
Also on this page: English and non-English articles, discussion fora, books, and secondary resources. Jens Meiert maintains an index of CSS properties.
Jens Meiert
maintains a list of CSS properties, including those in working drafts,
with links to the relevant specifications.
See separate page.
See German page.
See separate page.
CSS from the Ground
Up.
See separate page.
Mailing lists and Usenet News groups.
A selection of books on CSS (in no particular order). Note that I have not read most of them.
Håkon Wium Lie & Bert Bos: Cascading Style Sheets – designing for the
Web “written by the creators of CSS” (3rd edition,
Addison-Wesley, 2005, ISBN 0321193121). See errata. [CSS 2.1]
See separate page.
See separate page.
Resources that catalogue links to other resources. (Which makes this list a tertiary resource… )
The slides of all (public) presentations given by W3C staff can be found on the W3C Talks page.