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.
Advantages of Bootstrap:
Easy to use: Anybody with just basic knowledge of HTML and CSS can start using Bootstrap Responsive features: Bootstrap's responsive CSS adjusts to phones, tablets, and desktops Mobile-first approach: In Bootstrap, mobile-first styles are part of the core framework Browser compatibility: Bootstrap 4 is compatible with all modern browsers (Chrome, Firefox, Internet Explorer 10+, Edge, Safari, and Opera)