[ultimatedelman]

while the mixpanel CSS is awful, the facebook CSS is not much better. any time you have to use a class that is descriptive of what the element should look like (for instance, .mas, which presumably stands for Margin All Small), you've tightly coupled the structure to the presentation and failed at CSS. While the article gets the idea mostly right, the counterexamples it uses are just as bad practice.

[Pxtl]

The Facebook CSS is so utterly specific that they may as well use style attributes directly.