CSS or Cascading Style Sheets is a style sheet language used to style markup language. Markup languages include HTML, XHML, XML, and other XML-based languages. The most common use of CSS is to style HTML web pages. Although HTML doesn't need CSS to function, every web page would look the same without it. With CSS, you can target specific elements in a web page and change the look and arrangement on the page. CSS can make an embedded image small or cover the entire webpage as a background. You can enlarge a heading and apply a specific font to stand out from the rest of the page. Other things you can do with CSS include changing the color of elements, making elements float to one side of the page, and the list goes on. Every web page uses HTML, and every web page that has its unique look uses CSS.