What is Responsive Web Design

A site designed with RWD adapts the layout to the viewing environment by using fluid, proportion-based grids, flexible images, and CSS3 media queries,] an extension of the @media rule.

Responsive Web Design by Ethan Marcotte

Mobile First

Luke Wroblewski’s definition of mobile first consists of three core components:

1. The growth of mobile is a huge opportunity to reach more people than ever
2. The constraints of the mobile medium force us to focus on what really matters
3. The capabilities of mobile create opportunities to innovate

Mobile First by Luke Wroblewsk

Responsive Web Design Frameworks

The two of the most popular RWD frameworks are:

Bootstrap

Foundation