How to dynamically set the Shell TabBar colors

Setting the color dynamically for an element using a resource is done in the following way:

XAML

<ContentPage BackgroundColor="{DynamicResource backgroundcolor}"/>

Code behind:

App.Current.Resources["backgroundcolor"] = Color.Green;

The above code will change the backgroundcolor of the contentpage to green.

How can I dynamicaly change the colors of the new Shell tapbar if I declared the style as follows:

<Shell...>
<Shell.Resources>
        <Style x:Key="BaseStyle"  TargetType="Element">
            <Setter Property="Shell.BackgroundColor" Value="#455A64" />
            <Setter Property="Shell.ForegroundColor"  Value="{DynamicResource backgroundcolor}" />
            <Setter Property="Shell.TitleColor"  Value="#700606" />
            <Setter Property="Shell.DisabledColor"  Value="#B4FFFFFF" />
            <Setter Property="Shell.UnselectedColor" Value="Gray" />
        </Style>
</Shell.Resources>

<TabBar Route="animals"
                Title="Animals"
                FlyoutDisplayOptions="AsMultipleItems">
        <ShellContent Route="mainpage"
                      Style="{StaticResource BaseStyle}"
                      Title="Icon"
                      Icon="Icon.png"
                      ContentTemplate="{DataTemplate rv:MainPage}" />
</TabBar>
</Shell>