Modern UI

Microsoft Design Language (or MDL), previously known as Metro and modern UI, is a design language created by Microsoft, with a focus on typography and simplified icons, absence of clutter, increased content to chrome ratio ("content before chrome"), and basic geometric shapes. Early examples of MDL principles can be found in Encarta 95 and MSN 2.0. The design language evolved in Windows Media Center and Zune and was formally introduced as Metro during the unveiling of Windows Phone 7. It has since been incorporated into several of the company's other products, including the Xbox 360 system software, Xbox One, Windows 8, Windows Phone, and Outlook.com. Before the "Microsoft design language" title became official, Microsoft executive Qi Lu referred to it as the modern UI design language in his MIXX conference keynote speech. According to Microsoft, "Metro" has always been a codename and was never meant as a final product, but news websites attribute this change to trademark issues.

Microsoft Design Language 2 (MDL2) was developed alongside Windows 10. Later, the Fluent Design language extended it.