Fluent UI React components are themeable. We provide a set of sensible defaults, but you can override [colors](https://developer.microsoft.com/en-us/fluentui#/styles/web/colors/theme-slots) or [fonts](https://developer.microsoft.com/en-us/fluentui#/styles/web/typography) individually. See [this wiki](https://github.com/microsoft/fluentui/wiki/How-to-apply-theme-to-Fluent-UI-React-components) for more details.