bootstrap 4 - When to use reboot css and grid css?

I am trying to migrate my application from bootstrap 3.3.7 to Bootstrap v4.0.0-alpha.6.

When I downloaded the Bootstrap v4.0.0-alpha.6 into my project using NuGet, I saw bootstrap-reboot.css and bootstrap-grid.css in addition to bootstrap.css.

I tried to go through the document and understand their purpose but, I am not getting a clear picture.

What is the use of those two css files? Do I really need to include them in my project?

Solution 1:

bootstrap.css should contain all the CSS you need to use Bootstrap in your project.

The files bootstrap-reboot.css and bootstrap-grid.css are cut down versions containing just the necessary styles for reboot and Bootstrap's flexbox grid respectively. They are to be used if you don't want to include the entirety of Bootstrap in your project and will only be making use of either of these features.

The docs explain it here: https://getbootstrap.com/docs/4.1/getting-started/contents/#css-files