ThemeMode Inherits: Enum Describes which theme will be used by Flet app. Properties DARK – Always use the dark mode (if available) regardless of system preference. LIGHT – Always use the light mode regardless of system preference. SYSTEM – Use either the light or dark theme based on what the user has selected in the Properties# DARK = 'dark' # Always use the dark mode (if available) regardless of system preference. LIGHT = 'light' # Always use the light mode regardless of system preference. SYSTEM = 'system' # Use either the light or dark theme based on what the user has selected in the system settings.