Bootstrap 4 Grid System

Bootstrap is a frontend toolkit packed full of features. Backdrop CMS has included just the Grid System (boostrap-grid.css). It is being used extensively throughout Backdrop for Layouts.

Differences:

Backdrop is missing the html definition, and general element overrides for box-sizing:

html {
  box-sizing: border-box;
  -ms-overflow-style: scrollbar;
}
*,
*::before,
*::after {
  box-sizing: inherit;
}

Backdrop has added several additional viewport definitions:

@-webkit-viewport {
  width: device-width;
}
@-o-viewport {
  width: device-width;
}
@viewport {
  width: device-width;
}

In Backdrop, distance measurements have been converted from px to rems, but keeping distances the same assuming a 16px base font. 15px is now .9375rem;

Backdrop is missing the default width of a container being forced to 100%

.container {
  padding-right: .9375rem;
  padding-left: .9375rem;
  margin-right: auto;
  margin-left: auto;
}
.container-fluid {
  padding-right: .9375rem;
  padding-left: .9375rem;
  margin-right: auto;
  margin-left: auto;
}
      

.container {
  width: 100%;
  padding-right: 15px;
  padding-left: 15px;
  margin-right: auto;
  margin-left: auto;
}
.container-fluid {
  width: 100%;
  padding-right: 15px;
  padding-left: 15px;
  margin-right: auto;
  margin-left: auto;
}