FluentUI is a component-based UI framework that implements Microsoft's Fluent Design System for building cross-platform desktop applications. It provides a complete set of reusable UI components and styling tools that follow the Fluent Design language, enabling developers to create consistent visual interfaces across different operating systems.
The framework includes a custom window frame manager that creates frameless application windows with integrated title bars and standard window controls, styled through CSS variables. It also features a single-page application router that manages view navigation and session state within a single entry point, allowing for SPA-style desktop interfaces.
FluentUI offers a collection of desktop form input controls including various button types (filled, text, toggle, radio) and text input fields (single-line and multi-line). The framework's dynamic theme styling engine controls application appearance through global CSS variables for color palettes and spacing systems, while also providing icon and text rendering capabilities with consistent visual treatment.