Bootstrap is a matured, frontend framework that helps developers to build responsive (mobile-friendly) websites.
Note
What is Responsive Web Design? According to W3Schools (World Wide Web Schools: https://www.w3schools.com/bootstrap/bootstrap_get_started.asp), responsive web design is about creating websites that automatically adjust themselves to look good on all devices, from small phones to large desktops.
Bootstrap can be downloaded from https://www.w3schools.com/bootstrap/bootstrap_get_started.asp or added to a web page from Bootstrap CDN.
Some of the Bootstrap CSS classes require JavaScript code to work on websites.
The most recent version of Bootstrap at the time of writing is Beta.2.
Note
The example project can be found at https://github.com/polatengin/B05277/tree/master/Chapter18/0-GettingStartedBootstrap.
You should add these lines into the head section of the web page in order to use Bootstrap:
<script src="https://code.jquery.com/jquery-3.2.1.slim.min...