Bootstrap and the mobile-first design
In the beginning of Bootstrap, there was no concept of mobile-first. It was first used for responsive design web pages. With the Version 3 of the framework, the concept of mobile-first became very solid in the community.
The whole code of the scaffolding system was rewritten to become mobile-first from the start. They decided to reformulate how to set the grid instead of just adding mobile styles. This made a great impact in compatibility between versions older than v3, but was crucial for making the framework even more popular.
As we saw in the first chapter, to ensure the proper rendering of the page, set the correct viewport at the <head> tag:
<meta name="viewport" content="width=device-width, initial-scale=1">
