Responsive design is still a relatively new technique – however, it has already gone through several different incarnations of how we should be building these sites. In the first incarnation we started by adding media queries, adapting our site to work better on mobile devices. The second incarnation arrived with mobile first design: Building for the least capable, smallest devices and then using progressive enhancement to take advantage of larger screens and extra features that devices offered. This talk will focus on how we can reimagine responsive design with a focus on performance: Evolving a new incarnation where we aim to deliver a functioning site as quickly as possible to our users, then start to improve the experience as more of the content has loaded. As part of this we will look at how this impacts how a website is designed and how it is built.