18F: CSS coding style guide
Nested selectors are some of the least maintainable language features i have ever worked with. Once the number of embedded classes, or layers of embedding gets too big, the entire file descends to a bad place.Here is a real world example of what i am talking about, from a code base i currently work with, and don't dare touch:
http://i.imgur.com/fMlvoRS.pngThe idea of maintaining legacy sass with heavy embedding in years to come makes me shudder.