If you are not already familiar, start with Ethan Marcotte's original article Responsive web design.
The West Sussex County Council website is built responsively from the ground up, with a mobile-first approach. All core functionality should be available and usable on any size and capability of internet-connected device. The page load should be as low as possible for the size of screen.
Additional information
- Responsive Web Design: What It Is and How To Use It by Smashing Magazine
- What the heck is Responsive Web Design by John Polacek
- Beginner’s Guide to Responsive Web Design at Treehouse
- This is Responsive by Brad Frost