Responsive web design (RWD) is an approach to web design that makes web pages render well on a variety of devices and window or screen sizes. Recent work also considers the viewer proximity as part of the viewing context as an extension for RWD. Content, design, and performance are necessary across all devices to ensure usability and satisfaction.
The fluid grid concept calls for page element sizing to be in relative units like percentages, rather than absolute units like pixels or points.
Flexible images are also sized in relative units, to prevent them from displaying outside their containing element.
Media queries allow the page to use different CSS style rules based on characteristics of the device the site is being displayed on, e.g. width of the rendering surface (browser window width or physical display size).
Responsive layouts automatically adjust and adapt to any device screen size, whether it is a desktop, a laptop, a tablet, or a mobile phone.
Responsive web design has become more important as the amount of mobile traffic now accounts for more than half of the total internet traffic. Therefore, Google announced Mobilegeddon in 2015 and started to boost the ratings of sites that are mobile-friendly if the search was made from a mobile device. Responsive web design is an example of user interface plasticity.