Cascading Style Sheet is a way of styling your document. It is a set of commands which make a page much more interactive.

A Cascading Style Sheet, or CSS, is the kind of style sheet you will find in the head of a web page document. These style sheets control the presentation of the web page. This is done to separate the markup of the web page from the rules that control how that markup is to be styled and presented.

Style sheets are useful in web site development because it allows a designer to consolidate the rules required to style a web site into one place and one document. This will ultimately save the designer time. If the designer decides to change a style on the site, they only have to look in one document and one place to make the change and the change will take effect immediately. Furthermore, style sheets separate the rules that are purely for presentation from the content, which allows you to write leaner code.

CSS is short for Cascading Style Sheet. It is used to add styles to web pages.