Material You is a Google design principle that allows the user to customize their mobile experience with their preferred colour palette, making their choice seen across Google apps and widgets. It also represents a visual layout style in Google’s design that stays consistent.
The company has slowly updated its products to have the same visual style. This often includes making the app compatible with the colours selected by the user. Google News, Android Automotive, and Spark Mail are all recent apps that received the facelift.
Wear OS 3 is based on the Android 11 operating system, which was released in 2020. Material You was added as a part of Android 12 and newer, which is why Pixel Watches haven’t featured it until now. The shiny new Wear OS 4 will be based on Android 13.
Folks at XDA Developers were able to boot up Wear OS 4 and found the new Material You design language. The publication noted that it could not change the accent colours — the menus remained tinted with a light Blue highlight — but predicted that that feature wasn’t fully implemented yet.