The CSS used for this layout is 100% valid and hack free. To overcome Internet Explorer's broken box model, no horizontal padding or margins are used. Instead, this design uses pixel widths and clever relative positioning.
It doesn't matter which column has the longest content, the background colour of all columns will stretch down to meet the footer. This feature was traditionally only available with table based layouts but now with a little CSS trickery we can do exactly the same with divs. Say goodbye to annoying short columns!
There are two main ways to reference a div or any other HTML element from your style-sheet, you can use an id (id="idname") or a class (class="classname") so which one is best? Well the answer is it depends on what you are trying to do.
An id must be unique, this means you cannot have two elements on the one page with the same id. So an id is useful for something that never repeats on a page like a header or footer. Classes don't have to be unique so they can be used as many times as necessary. A good example of a repeatable element would be a link style, you can have as many links on a page as you like and they can all look the same by giving them the same class name.
Because the columns in this stackable design can be repeated any number of times we cannot use ids because they would be duplicated. Only classes allow us to repeat the columns as many times as we like. So please keep that in mind if you are modifying this design. Of course if your modified layout does not have repeated columns then you can change some of the classes back to ids.
This layout requires no images. Many CSS website designs need images to colour in the column backgrounds but that is not necessary with this design. Why waste bandwidth and precious HTTP requests when you can do everything in pure CSS and XHTML?
You don't have to pay anything. Simply view the source of this page and save the HTML onto your computer. My only suggestion is to put the CSS into a separate file. If you are feeling generous however, link back to this page so other people can find and use this layout too.