CSS: The bad bits (and how to avoid them)

The more I use CSS, the more I think it’s an absolute wild wild west. It’s mature, ubiquitous, yet lacks basic, common-sense features that come as a given in other similar tools. After working with several modern MVC web apps that have well architected back-ends, extensive test coverage and good documentation, I often find the stylesheets to be giant steaming piles of spaghetti garbage.