The missing grid range in Bootstrap 3, below sm, from 480 to 767 pixels, redefining xs to less than 480 pixels.

• https://AndersDJohnson.github.io/bootstrap-grid-ms/test/index.html
• https://AndersDJohnson.github.io/bootstrap-grid-ms/test/index-sass.html

bower install --save bootstrap-grid-ms

Use the col-ms-*, hidden-ms, visible-ms, and visible-ms-* classes, e.g.:

<div class="col-ms-6">
  ...
</div>

Using LESS or SCSS/Sass, you can redefine the default Bootstrap breakpoints, and bootstrap-grid-ms will respect those.

You will need Bootstrap LESS installed, e.g. via Bower:

bower install --save bootstrap

In your LESS, somewhere after importing Bootstrap, import the LESS file:

@import "bower_components/bootstrap/less/bootstrap";
@import "bower_components/bootstrap-grid-ms/less/bootstrap-grid-ms";

You will need an SCSS/Sass version of Bootstrap, which is not included in this module's default Bower dependencies.

bower install --save bootstrap-sass

In your SCSS/Sass, somewhere after importing Bootstrap, import the SCSS file:

@import "bower_components/bootstrap-sass/assets/stylesheets/bootstrap";
@import "bower_components/bootstrap-grid-ms/scss/bootstrap-grid-ms";

Or use the CSS file, somewhere after Bootstrap:

@import "bower_components/bootstrap-grid-ms/dist/bootstrap-grid-ms.min.css";

Originally taken from from: https://gist.github.com/wdollar/135ec3c80faaf5a821b0

Original notes:

This is a hack to fill the gap between 480 and 767 pixels - a missing range in the bootstrap responsive grid structure. Use these classes to style pages on cellphones when they transition from portrait to landscape.

Contains: Columns, Offsets, Pushes, Pulls for the Mid-Small layout
Visibility classes for the Mid-Small layout
Redefined visibility classes for the Extra Small layout

See twbs/bootstrap#10203 for more info.
Forked from: https://gist.github.com/Jakobud/8eca95f07a3b50453cd7
Original gist: https://gist.github.com/andyl/6360906