Responsive Web design is a method whereby a designer creates a Web page that “responds to” or resizes itself depending on the type of device it is being seen through.  That could be a large  desktop computer monitor, a laptop, a 10-inch tablet, a 7-inch tablet, or a 4-inch smartphone screen.

This is due in part to the  growth of smartphones and other mobile devices. More people are using smaller-screen devices to view Web pages.  Therefore, it is important that your website can adapt to any screen size, today or in the future.