Flat design is an interface design style that is minimalist. Typical features include simple, two-dimensional elements and vivid colors.
This style is often compared to the skeuomorphic style, which gives the illusion of three-dimensionality by replicating properties found in real life. Flat design was initially developed for responsive designs, where a website's content is scaled based on the device's screen size. Since flat design relies on minimal textures and simple shapes, it ensures that responsive designs load quickly (especially important since mobile devices tend to have slower connection speeds). With a flat design, one can reduce visual noise (that appears in form of shadows and textures) to make the user experience more streamlined and optimized.