<ContentPage.Resources>

        <ResourceDictionary x:Name="AppDictionary">


            <Color x:Key="BackgroundColor">#000000</Color>
            <Color x:Key="BorderColor">#E1E1E1</Color>
            <Style x:Key="InternalViewStyle" TargetType="ContentView">
                <Setter Property="BackgroundColor" Value="{StaticResource BackgroundColor}"/>
                <Setter Property="VerticalOptions" Value="Fill"/>
            </Style>
            <Style x:Key="BorderStyle" TargetType="ContentView">
                <Setter Property="BackgroundColor" Value="{StaticResource BorderColor}"/>
            <Setter Property="Padding" Value="3,1,1,3"/>
            </Style>

        </ResourceDictionary>
   
        
    </ContentPage.Resources>


    <ContentView Padding="20" VerticalOptions="Center" HorizontalOptions="Center">
        <ContentView Style="{StaticResource BorderStyle}" >
            <ContentView Style="{StaticResource InternalViewStyle}">
                <Label Text="I am Border 1!"
               FontSize="20" TextColor="White"
               HorizontalOptions="Center"></Label>
            </ContentView>
        </ContentView>
    </ContentView>