Metro is a design language created by Microsoft originally for Windows Phone to emphasize typography over graphics. Key principles include putting content first, relying on animation and motion, and focusing on large text for quick comprehension. Inspired by public transit signage, Metro aims to be sleek, modern, and a refresh from icon-based interfaces. It was later applied to additional Microsoft products and platforms like Windows 8 to consolidate common tasks and favor larger interactive hubs over smaller buttons through lateral scrolling and exclusion of unnecessary visuals.