Responsive web design and development refers to the approach of creating websites that provide an optimal viewing experience across a wide range of devices and screen sizes. With the increasing use of smartphones, tablets, and various other devices to access the internet, it is essential to ensure that websites are designed and developed in a way that they adapt and respond to different screen resolutions and orientations.

The key principle behind responsive web design is to build websites that fluidly adjust their layout, content, and functionality based on the device being used to access them. This means that regardless of whether a user is accessing the website on a desktop computer, a laptop, a tablet, or a smartphone, the website will automatically adjust and display appropriately, providing a seamless and user-friendly experience.