What is a Style Sheet?

A style sheet is a series of style rules that can be linked to elements in an HTML document. IE4 implements style sheets through the use of Cascading Style Sheets (CSS). Cascading Style Sheets were developed by W³C to provide a standard for effective markup, layered text and images, and exact positioning of items. IE4 and Dynamic HTML build on the W³C CSS specification to enable faster and more interactive Web pages. What exactly are the advantages of learning yet another addition to HTML?