A free and open solution, developed by those who use it. Silex is a professional site builder, with no subscriptions and no limitations.

Micromodal.js is a lightweight, configurable and a11y-enabled modal library written in pure JavaScript

Primer CSS is a CSS framework built by Github. It provided several ready mae components like breadcrumb, buttons, navigation pagination ... Their approach to CSS is influenced by Object Oriented CSS principles, functional CSS, and BEM architecture.