Is CSS case sensitive?

[Lemosys]

Cascading Style Sheets (CSS) is not case sensitve. However, font families, URLs to images, and other direct references with the style sheet may be.

The trick is that if you write a document using an XML declaration and an XHTML doctype, then the CSS class names will be case sensitive for some browsers.

It is a good idea to avoid naming classes where the only difference is the case, for example:

div.myclass { ...}
div.myClass { ... }