CSS Level 2 became a W3C recommendation in May 1998, and it is published at http://www.w3.org/TR/REC-CSS2/. CSS Level 1 became a W3C recommendation in 1996, with a revision in January 1999. It is published at http://www.w3.org/TR/REC-CSS1. Work on CSS Level 3 is ongoing, and links to specifications may be found at http://www.w3.org/Style/CSS/current-work.
CSS is a stylesheet language that allows authors and users to attach styles (e.g., fonts, spacing, and sounds) to structured documents such as HTML documents and XML applications. By separating the presentation style from the content of a document, CSS simplifies web authoring and site maintenance.
CSS2 builds on CSS1, and with few exceptions, all stylesheets valid in CSS1 are also valid in CSS2. CSS2 supports media-specific stylesheets, so authors can tailor the presentation of their documents to visual browsers, aural devices, printers, Braille devices, hand-held devices, etc. This specification also supports content positioning, downloadable fonts, table layout, internationalization features, automatic counters and numbering, and some user interface properties.
XSL became a W3C Recommendation in October 2001. The specification is published at http://www.w3.org/TR/xsl/.
XSL is a language for formatting XML documents. It consists of an XML vocabulary of formatting objects (XSL-FO) and a language for transforming XML documents into those formatting semantics (XSLT). An XSL stylesheet specifies the presentation of a class of XML documents by describing how an instance of the class is transformed into an XML document that uses the formatting vocabulary.
XSLT became a W3C Recommendation in November 1999. The specification is published at http://www.w3.org/TR/xslt/. A working draft of XSLT 2.0 may be found at http://www.w3.org/TR/xslt20.
XSLT is a language for transforming XML documents into other XML documents. It is designed for use as part of XSL, which is a stylesheet language for XML. XSL also includes an XML vocabulary for specifying formatting, and uses XSLT to describe how the document is transformed into another XML document that uses the formatting vocabulary.