theming Shipped
What this lens looks for
WinUI 3 tri-state theming — Light, Dark, High Contrast; set app-level theme via Application.RequestedTheme; always use ThemeResource (not StaticResource) for colors and brushes to enable runtime switching; use semantic color resources (TextFillColorPrimary, CardBackgroundFillColorDefault) not hex values; define custom theme-aware colors in ResourceDictionary with Default/Light/Dark dictionaries
What its verifier checks
No hex color values in XAML; ThemeResource used exclusively for colors and brushes; app renders correctly in Light, Dark, and High Contrast modes; custom colors defined with theme dictionary variants