Theme resources These resources are used in the control's default style. Dark theme brushes To change the colors of the control in the dark theme, override these brushes in App.xaml. <SolidColorBrush x:Key="ThumbBackgroundThemeBrush" Color="#FFCDCDCD" /> <SolidColorBrush x:Key="ThumbBorderThemeBrush" Color="#3B555555" /> <SolidColorBrush x:Key="ThumbPointerOverBackgroundThemeBrush" Color="#FFDADAD
![Thumb styles and templates (Windows)](https://cdn-ak-scissors.b.st-hatena.com/image/square/d6e4cb632c7025e9f5e05fd314fbf6dcd6144e8d/height=288;version=1;width=512/https%3A%2F%2Flearn.microsoft.com%2Fen-us%2Fmedia%2Fopen-graph-image.png)