This might be not really cutting-edge but I was stuck in a crib for a while.
Today I discovered Polymer and Google Material Design Lite (MDL) via this nice article on medium.
As my previous cutting-edge bar was SASS, Bootstrap and Flux + React so this discovery made my day.
I can say I know Bootstrap enough to be able to work with it, I had just a bite of the others.
Anyway, in a lurking sprint, I was positively surprised by BEM and SMACSS: two approaches (with some in common) on how to write css and html in a non-messy way.
I have to admit I was always wondering how to organize my web code because no way: the css will always be messy.
So below a short list of other things to try, read or watch
scss_lint [scss-lint is a tool to help keep your SCSS files clean and readable. You can run it manually from the command line, or integrate it into your SCM hooks.]
About HTML semantics and front-end architecture
Building My Health Skills — Part 3 [This is about devs experience on the use of BEM]
An Introduction To Object Oriented CSS (OOCSS)
The single responsibility principle applied to CSS
The open/closed principle applied to CSS
Manage large-scale web projects with new CSS architecture ITCSS