1. Simple and flexible HTML, CSS, and JS for popular UI components and interactions

  2. The most advanced responsive front-end framework in the world

  3. A UI Component library implemented using a set of specifications designed around natural language

  4. A set of small, responsive CSS modules that you can use in every web project.

  5. A lightweight and modular front-end framework for developing fast and powerful web interfaces

  6. A modern responsive front-end framework based on Material Design

  7. Bulma is an open source CSS framework based on Flexbox and built with Sass. It's 100% responsive, fully modular, and available for free.

  8. A Beautiful Boilerplate for Responsive, Mobile-Friendly Development

  9. Lightweight, responsive and modern CSS framework for faster and extensible development.

  10. The Write Less, Do More, JavaScript Library.

  11. A rock-solid default for HTML5 awesome.

  12. Responsive HTML5, CSS and JavaScript Framework