Windows 11 has a lot of small touches that are designed to bring the operating system feel more lively. One of those is Microsoft’s signature design material dubbed “Mica,” and as part of evolving Windows, the company recently updated developer documentation to mention a new form of this material, “Mica Alt.”
For those unfamiliar with Microsoft’s marketing terms, Mica is a design material in Windows 11 that brings in small elements from the Windows theme as well as in the desktop wallpaper into the title bar of apps. It is best visible with the light theme but also works in dark modes as well. The new Mica Alt theme is similar to this, but with one tweak. It now more strongly tints the color of your desktop background color. You can see Microsoft’s sample image below, where the red background slightly bleeds through the window that has Mica Alt enabled. It’s a difference that’s really hard to notice at first glance. But with a closer look, you can see how it better highlights the Windows 11 wallpaper with a bit more of a see-through glass-like feeling.
Generally speaking, this isn’t something you’ll see in every app just yet. It’s up to developers to enable it at the base layer of their apps. The full documentation gets into when Microsoft suggests Mica to be used in all layering, and when it should not. The Mica effects also only work in UWP apps that use WinUI 2, or in apps that use Windows App SDK 1.1 or higher.
This would be just the latest design touch added to Windows 11 by Microsoft. Along with a new Taskbar zoom-in animation on login, the company was also A/B testing new animated icons in the Windows 11 settings app. Those were part of adding “delightful unexpected moments of joy” to the operating system.