Cascading Style Sheets is a style sheet language, meaning that it expresses the presentation of a structured document. In practice, it describes and formats web pages written in the HTML and XHTML markup languages, and can also be used for XML, SVG and XUL. It was developed by the World Wide Web Consortium and released in 1996. CSS defines distinct elements such as layouts, fonts and colours, which helps to make content more accessible by distinguishing between the logical structure of a web page and its presentation, and is adaptable to the varying display requirements of different devices.