From Xojo Documentation
New in 2019r3
The ColorGroup class allows you to do dynamic light/dark target color selection.
Comparisons and Conversions
A ColorGroup can be directly compared to a Color value to determine if they are the same. It's important to remember of course that you can comparing the known color to the color of the ColorGroup at that moment as a ColorGroup can return different colors based upon the state of the device.
Canvas1.DrawingColor = Color.Blue
Canvas1.DrawingColor = Color.Red
When you assign a ColorGroup to a Color property or variable, the color you receive the is color at that moment. For example, in a ColorGroup set to dual color, if you ask for the color when the device is in dark mode, you'll get the dark color.
Assigning a color to a ColorGroup assigns it to the Light Color (the default).
You can assign a named color to a ColorGroup by setting the ColorGroup equal to the name:
For macOS and iOS, Apple provides a complete list of valid named colors. These colors will automatically switch between light and dark modes. Apple's Adaptable System Colors will also automatically switch between light and dark modes but the Fixed Colors will not.
When using a name from Apple's documentation, the case must match as well.