What is Bootstrap?

Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains HTML, CSS, and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.

Bootstrap was created by Mark Otto and Jacob Thornton in 2011, and it has become one of the most popular CSS frameworks in the world. It is used by millions of developers to create websites and web apps that are responsive, accessible, and easy to maintain.