Microsoft has been tweaking the existing Windows 11 design materials and even adding new ones to the list. Now, it has added one more new design material to the official documentation. The new material “Mica Alt” is a variant of the existing Mica material, with stronger tinting of the user’s desktop background color.
The below image provided by Microsoft demonstrates the difference between Mica and Mica Alt. One can notice the effect if stronger tinting in Mica Alt.
Microsoft recommends using Mica Alt when creating an app with a tabbed title bar. It provides a deeper visual hierarchy than Mica material in apps.
Mica Alt is a variant of Mica, with stronger tinting of the user’s desktop background color. You can apply Mica Alt to your app’s backdrop to provide a deeper visual hierarchy than Mica, especially when creating an app with a tabbed title bar. Mica Alt is available for apps that use Windows App SDK 1.1 or higher, while running on Windows 11 version 22000 or later.
When to use Mica or Mica Alt
Mica and Mica Alt are materials that appear on the backdrop of your application — behind all other content. Each material is opaque and incorporates the user’s theme and desktop wallpaper to create its highly personalized appearance. As the user moves the window across the screen, the Mica material dynamically adapts to create a rich visualization using the wallpaper underneath the application. In addition, the material helps users focus on the current task by falling back to a neutral color when the app is inactive.
We recommend that you apply Mica or Mica Alt as the base layer of your app, and prioritize visibility in the title bar area. For more specific layering guidance see Layering and Elevation and App layering with Mica.