<Style x:Key="BaseStyle" TargetType="Element">
        <Setter Property="Shell.BackgroundColor" Value="Green" />
        <Setter Property="Shell.ForegroundColor" Value="Red" />
        <Setter Property="Shell.TitleColor" Value="Blue" />
        <Setter Property="Shell.DisabledColor" Value="Red" />
        <Setter Property="Shell.UnselectedColor" Value="Yellow" />
        <Setter Property="Shell.NavBarHasShadow" Value="False" />
        <Setter Property="Shell.TabBarBackgroundColor" Value="Blue" />
        <Setter Property="Shell.TabBarForegroundColor" Value="Red" />
        <Setter Property="Shell.TabBarTitleColor" Value="Red" />
        <Setter Property="Shell.TabBarUnselectedColor" Value="Yellow" />
    </Style>
    <Style BasedOn="{StaticResource BaseStyle}" TargetType="ShellItem" ApplyToDerivedTypes="True" />
        
    <Style TargetType="TabbedPage">
        <Setter Property="BarBackgroundColor" Value="Red" />
        <Setter Property="BarTextColor" Value="Red" />
        <Setter Property="UnselectedTabColor" Value="Yellow" />
        <Setter Property="SelectedTabColor" Value="Red" />
    </Style>