Fluent 2 is Microsoft's own official design system: the actual components, tokens, and guidelines behind Teams, Loop, Office, and Windows, published as a free Figma UI kit mapped to real code libraries.
Using Fluent 2 means matching real, current Microsoft product conventions exactly, not guessing at what a "Microsoft-style" interface should look like from screenshots.
Essential if you're designing anything that plugs into the Microsoft ecosystem: a Teams app, an Office add-in, an Azure-adjacent tool.
It's genuinely large and opinionated toward Microsoft's own product patterns, so expect some adaptation work if you're borrowing components for a non-Microsoft context.
