public partial class App : Application
{
    public App()
    {
        TelerikLocalizationManager.Manager.ResourceManager = AppResources.ResourceManager;

        InitializeComponent();

        TelerikThemeResources.AppTheme = TelerikTheme.PlatformDark;

        if (TelerikThemeResources.AppTheme.ToString().EndsWith("Dark"))
        {
            Application.Current.UserAppTheme = AppTheme.Dark;
        }
    }

    protected override Window CreateWindow(IActivationState? activationState)
    {
        return new Window(new MainPage());
    }
}