Bootstrap has one of the best responsive, mobile-first grid systems available. It’s built with Flexbox and it’s easy to use. It helps in scaling a single website design from the smallest mobile device to high-definition displays, logically dividing the screen into 12 columns, so that you can decide just how much screen real estate each element of your design should take up.

Bootstrap comes complete with many JavaScript components and reusable CSS that can help to achieve the functionality needed in almost any kind of website. You just have to use some HTML to plug them into your template, with no need to spend huge amounts of time writing complex CSS and JavaScript. Plus, all these components are responsive, too!

Bootstrap is fully compatible with the latest, stable releases of all major browsers and platforms. With regard to the Windows platform, Bootstrap works in Microsoft Edge and Internet Explorer versions 10–11.

Bootstrap is offering many ways to customize its default design. You can easily override all of its CSS and default JavaScript behavior. Bootstrap is even more interesting if you’re a Sass developer, as it also gave you a chance to customize your Sass template. These options let you smoothly to create a wonderful template using Bootstrap.

Bootstrap is an open-source project that’s released under the MIT license and hosted on GitHub .

SitePoint has published a book on Bootstrap called “Jump Start Bootstrap”. It teaches you how to get started with Bootstrap. You will know how to use Bootstrap’s components and plugins, it also covers how to customize them through options like Less and Sass. A major section has been dedicated to Bootstrap’s grid system, which is the most important aspect to create a responsive website design. If you want then you can learn to create many demo website designs throughout the book.