Bootstrap is one of the most popular HTML / CSS frameworks that allows you to quickly build responsive page layouts and offers a wide range of ready-made CSS elements for the front-end. Bootstrap also ensures high compatibility and stability of elements operation in different browsers. The framework not only provides ready-made UI elements and components, but also has a rich collection of JavaScript scripts that are often used in web development. Bootstrap is most effective when building business applications and internal tools, where we cannot always or want to involve a UI designer in the project.