Really interesting piece by Adam Morse: CSS and Scalability
I also started to think about communication and how it moves in multiple directions. If I’m reading html, I want to know what the css is going to do. If I’m reading css I want to know what will happen if I apply it to a block of html. In a great system there is a two way street of information. If you look at the CSS, you can tell what will happen. If you look at the html, you know what the code will do.
Along with some great tools
And also an older one from August 2014: Good CSS
On kinda the same topic by Jonathan Snook: Scalable and Modular Architecture for CSS
and in the same vein but about HTML Semantics by Nicolas Gallagher from March 2012.