Airbnb style guides
A style guide is a set of standards that outline how code should be written and organized, contains general rules about how to write code like which quotes to use, how many spaces to indent, where to put line breaks, etc.
React/JSX Style Guide
CSS-in-JS Style Guide
CSS/Sass Style Guide
A mostly reasonable approach to CSS and Sass that covers naming conventions, formatting, ordering, variables, etc. Also available in many languages.
Ruby Style Guide
This is Airbnb's Ruby Style Guide, was inspired by GitHub's guide and RuboCop's guide.