Bootstrap

It's a free, open source and most popular HTML, CSS, JavaScript framework developed by twitter for creating responsive web application.

Advantages

1) Support Responsive Design
2) Consistency
3) Saves development time
4) Customizable

Bootstrap Grid System - Used for creating page layout
It consist of 12 column.

Grid Classes

Extra Small Devices - Mobile
Small Devices - Tablet
Medium Devices - Desktop
Large Devices- Desktop



If you have any questions, post here. Also, provide your valuable suggestions and thoughts in form of comments in the section below.

Thank you !!!