What is RWD responsive web design
Media queries allow you to test or check the width of a device viewport. This simple check is at the root of serving up the content or presentation you want to display based on the device in use.
Users access content with many different devices. These devices have different viewport aspect ratios (width and height) and different pixel densities. A developer must also take into account if the user is holding the device in portrait or landscape view.
There are a lot of variables a developer must take into consideration. User experience is a huge factor we must consider. At the core of UX is our enemy latency. We must reduce content, file or image size, and server requests as must as possible. However, we must provide the most robust and visually interesting interface and experience as possible. Is developing the perfect UX easy? No. Is developing the perfect UX a challenge? Yes. Oh, if this helps then great. There is no perfect.