Style sheets describe how documents are presented on screens, in print, or perhaps how they are pronounced. W3C has actively promoted the use of style sheets on the Web since the Consortium was founded in 1994. The Style Activity has produced several W3C Recommendations (CSS1, CSS2, XPath, XSLT). CSS especially is widely implemented in browsers.
By attaching style sheets to structured documents on the Web (e.g. HTML), authors and readers can influence the presentation of documents without sacri ficing device-independence or adding new HTML tags. Cascading Style Sheets (CSS)is a style sheet language used for describing the presentation semantics (the look and formatting) of a document written in a markup language. and CSS is used for formatting structured. CSS offers more options and is more accurate and sophisticated. CSS is supported by all browser today. CSS was invented to remedy this situation by providing web designers with sopistecated layout oppurtunities suppoted by all browsers. at the sametime seperation of the presentation style of documents from the content of documents , makes site maintenance a lot easier.