What is CSS?
Cascading Stylesheets (CSS) is a web design and development technique which has quickly become the de-facto standard for creating web pages. The main purpose of using HTML and CSS is to separate presentation from content: HTML is used for the text and images, while CSS is used to determine their position and look on the page, as well as the layout characteristics of the page itself. A third element -- scripting, is used to control site behavior.
Like HTML, CSS can be written in any text editor.
The precursor to modern CSS was unveiled in October 1994 by Norwegian developer Håkon Wium Lie. By the end of 1996 W3C had pubished CSS level 1 Recommendation. CSS level 2 was created in 1997. It was published as a W3C Recommendation on May 12, 1998, and remains the current standard. CSS level 3, which was started in 1998, is still under development.