It used to be that websites needed to fit just a couple of different screen sizes, but these days there are a myriad of different devices, all of which have a different screen size and resolution, from a small iphone right up to the largest screens on a desktop computer.
Generally websites would be difficult to see properly on the smaller screens, necessitating scrolling horizontally as well as vertically, not looking great at all, or even not working.
But now this is solved with Responsive Web Design, or RWD as it is often known.
When we design a website, we ensure it looks great and works on any device, no matter what the size of the screen.
Do you know what your website looks like on a mobile phone?