In the past, we used desktop computers or laptops to access large web applications. But these days users tend to use various kinds of mobile-based devices to access large web applications. Even e-commerce based applications are available on mobile and, unlike in the past, users are not afraid of doing transactions through mobiles. So responsive design has become a must in website and application design. If we don't consider responsive design, users will have major limitations in accessing the application through mobiles and hence we could lose many potential users of the application.
Until recently, we had to use other plugins or third-party services to check the responsiveness of your application screens. WordPress 4.5 introduced responsive previews in the theme customizer where we can check different screen sizes instantly without needing any other service. We can go...