WPF - Add Custom Font

<Window.Resources>
    <Style x:Key="Gotham-XLight">
        <Setter Property="TextElement.FontFamily" Value="/CustomFonts;Component/#Gotham-XLight" />
    </Style>
</Window.Resources>

<TextBlock x:Name="TimeTextBlock" Style="{DynamicResource Gotham-XLight}" TextAlignment="Center" FontSize="25" FontWeight="Bold" Foreground="White" Text="TextBlockTimer" Margin="105,242.974,0,226.975" HorizontalAlignment="Left" Width="221.919" />

<Window.Resources>
    <Style x:Key="Gotham-XLight">
        <Setter Property="TextElement.FontFamily" Value="CustomFonts/#Gotham-XLight" />
    </Style>
</Window.Resources>