What Is a Style Sheet?
Style sheets are nothing new. They've actually been around for quite some time. If you've had any experience working with word processing or desktop publishing programs (such as Microsoft Word or Adobe PageMaker), you've already used style sheets—you just might not have been aware that you were using them.
Style sheets have their origin in the world of desktop publishing. Programs such as PageMaker, Quark Xpress, and Ventura Publisher allow you to assign formatting characteristics to what are variously called styles or tags. The formatting characteristics that are assigned can then be applied to a document by applying the style, rather than having to re-apply the same formatting characteristics each and every time.