If you run into problems developing with CSS, check the CSS Support Charts to determine if there is a problem with the browser(s) you are using. The CSS Support Charts comprise three charts: Mastergrid, Historical CSS1 Support, and CSS2 Selectors. The Mastergrid chart looks at current generation support for CSS1 properties, while the Historical CSS1 Support chart covers the browsers that support CSS but were launched before 2000. The CSS2 Selectors chart covers the level of support in browsers for CSS2 selectors.
This is the official site for CSS. At this site you can learn about the history of CSS, investigate learning resources and authoring tools, and read current CSS news.