Bootstrap is an open source toolkit for developing with HTML, CSS, and JS.

npm install bootstrap@4.0.0-beta.3
Bootstrap Select (for Dropdowns)

Bootstrap-select is a jQuery plugin that utilizes Bootstrap's dropdown.js to style and bring additional functionality to standard select elements.

npm install bootstrap-select
Include Media (for Media Queries)

Include-media is a Sass library for writing CSS media queries in an easy and maintainable way, using a natural and simplistic syntax.

npm install include-media