Style sheets have been around since the early 1990s along with the beginnings of HTML. As HTML grew CSS came to carry a wider variety of stlye capabilities to meet the demands of the web industry.
The idea of formatting content with CSS was originally proposed in 1994 by Håkon Wium Lie. Bert Bos was at the time working on a browser called Argo which used its own style sheets; the two decided to work together to develop CSS.
Although other style sheet languages had been proposed, CSS carried an idea that others lacked, which was the concept of "cascading" or the ability to inherit document styles from more then one style sheet. This gave developers greater flexibility and control.
CSS was proposed at the "Mosaic and the Web" conference in Chicago in 1994, and again in 1995. During this time the World Wide Web Consortium was being established; they took an interest in the development of Cascading Style Sheets. By the end of 1996, CSS was nearly ready to become official. The Cascading style sheetslevel 1 Recommendation was published in December 1996.
Early in 1997, CSS was assigned its own working group within the W3C, chaired by Chris Lilley. The group began tackling issues that had not been addressed with CSS level 1, resulting in the creation of CSS level 2, which was published as an official Recommendation in May 1998. CSS level 3 is still under development as of 2004.