I am starting to learn more about CSS and its various functions, in the past I've used css strictly for style formatting such as color, font type, size, etc. But now I am learning that it also has other very useful functions. It's a good way to customize your page layout. This site will give you the code for various layout templates written in CSS. div tags and span tags are a big part of dictating how a page is laid out. A css stylesheet is a page composed strictly of CSS coding(external CSS), you can apply one sheet to many pages so that they all have the same layout and styles, or you can incorporate the css directly into a page of html(inline CSS).