Bootstrap package includes:
Scaffolding: Bootstrap gives a fundamental structure Grid System, link styles, and background.
CSS: Bootstrap provides the features of global CSS settings, fundamental HTML elements style and an advanced grid system.
Components: Bootstrap provides lots of reusable components built to provide iconography, dropdowns, navigation, alerts, pop-overs, and much more.
JavaScript Plugins: Bootstrap also contains a number of custom jQuery plugins. We can easily include them all or one by one.
Customize: Bootstrap provides the customizable components. We can customize Bootstrap’s components, LESS variables and jQuery plugins to get our own style.