Cascading Style Sheets is a simple mechanism that demonstrates how a document will be displayed onscreen, how it is going to print, or how information obtained from powerpoint slides will be displayed in a document. This style demonstration offers the developers total control over the style and format of their documents.

CSS is used to style HTML and XML documents and separates the content of the presentation. The Styles define the way in which HTML and XML are displayed. CSS allows Web developers the ability to control the style and format of multiple Web pages at the same time. All changes are marked so that an element in CSS will affect all the linked pages to that particular CSS in which the element appears.