Microsoft is releasing a preview of the Fluent XAML Theme Editor application today, it first announced the preview at its Build 2018 conference. For developers using XAML, today's release helps easily create apps with Fluent Design using their own themes for their apps.
With this first preview release of the Fluent XAML Theme Editor application, developers will be able to choose three major colors for both the Light and Dark themes, as well as minor colors that will apply to certain controls or borders. The tool also comes with Contrast ratio checking to make sure that themes are contrast compliant.
The Fluent XAML Theme editor is currently available for Windows Insiders with the Windows 10 SDK Preview Build 17723 or newer, and developers can get it from the dedicated GitHub repository (https://github.com/Microsoft/fluent-xaml-theme-editor). You can learn more about how to get started on the Windows developer blog.