airbnb/javascript ? reverse-engineered prompt

Build me a polished JavaScript style guide repo that a team could actually use to keep their code consistent.

I want a big readable README with a clear table of contents and practical rules for modern JavaScript, things like using const and let, objects, arrays, strings, functions, arrow functions, classes, modules, comments, whitespace, semicolons, naming, testing, and performance. Each rule should explain why it exists and show simple bad and good code examples.

Also include installable ESLint configs for regular JavaScript and React, with setup instructions so someone can add them to a project and start linting. Add separate guide pages for React and CSS in JavaScript. Keep the tone friendly and opinionated, like a mostly reasonable approach rather than a textbook.

Please set up the package files, basic scripts, examples, license, and contributor docs so it feels like a real open source style guide. Look up current ESLint docs online if you need to.