What is CSS?

Cascading Style Sheets (CSS) is a stylesheet language used to control the presentation of websites.

CSS was first introduced by Håkon Wium Lie in 1994 while working at the European Organization for Nuclear Research (CERN) alongside Tim Berners-Lee, the inventor of the World Wide Web. At the time, webpages were typically created exclusively with HTML, the Hypertext Markup Language that Berners-Lee had developed in the 1990s.

However, HTML had been developed to describe the semantics of a web document’s components (such as its headings and paragraphs) rather than provide style instructions. As the growing use of HTML to style webpages became increasingly unwieldy, CSS was introduced to provide a more efficient method for styling websites in conjunction with HTML. Today, along with HTML and JavaScript, CSS is one of the core technologies supporting the World Wide Web.

For more educational resources related to CSS, please visit:

• How To Build a Website with CSS Tutorial Series
• How To Build a Website with CSS Workshop Kit
• How To Build a Website with CSS eBook

A complete list of educational resources related to CSS is available on our CSS page.