Responsive Design is Google’s preferred design pattern for mobile-friendly sites. Responsive design allows the website to adapt to fit whatever device it’s being viewed on. Responsive websites are designed to fit the screen of whatever type of device your visitors are using. You can use CSS to make the web page “respond” to the device size. This is ideal because it prevents visitors from having to double-tap or pinch-and-zoom in order to view the content on your pages.