CSS Zen Garden, here, is a magnificent website. The amazing thing about it is that the layout changes constantly, being updated by different people, illustrating their web development skills and the vast possibilities of CSS.
Of the three websites, Modohead, CSS Zen Garden, and Hongkait, The Zen Garden was by far my favorite because it shows the uniqueness that CSS provides and how different people can express their creativity through the language. The constant switching that the website does is phenomenal and is an excellent way to display the many possibilities that CSS has.
CSS Zen Garden's home page proved to have only four warnings according to W3C Validator. That's quite fascinating that site with so much detail manages to have almost no warnings or errors. Moving to another page on the site, here , the validator finds only 4 warnings once again. With CSSZenGarden, nothing changes between the editions except for the CSS code. Of course, this means that the HTML between editions is the same, and thus will get the same results when validated.
The site's design gets a 9 out of 10. Perfection is hard to come by and, while the site looks phenomenal in each of its editions, there are definitely some areas that could be improved on such as colors or the chosen imagery. On the other hand, the site's usability isn't quite there. Aside from help with CSS and maybe HTML, the site doesn't come off as useful. 3/10 for usability.
As far as purpose, the site meets it and does so well. The site, simply put, is set out to display the power of CSS, and there's no question it does that. All-in-all, CSSZenGarden.com accomplishes what it was set out to do quite well.