Preprocessors are an extremely handy tool when writing your CSS, and although proprocessors are also available for languages like Javascript (CoffeeScript) and HTML (HAML, Jade) we are only interested in the CSS preprocessors.

There are two main flavours of CSS preprocessors, LESS and SASS.  We built this site using the SASS language partly because I had recently attended the Web Directions South whose speakers focussed more on SASS, and it was also what Chris Coyier had used with the V10 redesign of CSS Tricks and we were going through the videos at the time of the build.