App.xaml

<Application x:Class="FluentTest.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             ShutdownMode="OnMainWindowClose"
             StartupUri="TestWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="pack://application:,,,/Fluent;component/Themes/Generic.xaml" />

                <!--<ResourceDictionary Source="pack://application:,,,/Fluent;component/Themes/Themes/Light.Green.xaml" />-->

                <!--<ResourceDictionary Source="pack://application:,,,/Fluent;component/Themes/Themes/Dark.Green.xaml" />-->
            </ResourceDictionary.MergedDictionaries>

            <Style x:Key="{x:Type CheckBox}"
                   TargetType="CheckBox">
                <Setter Property="Foreground" Value="{DynamicResource Fluent.Ribbon.Brushes.Black}" />
                <Setter Property="VerticalAlignment" Value="Center" />
                <Setter Property="VerticalContentAlignment" Value="Center" />
            </Style>

            <Style TargetType="{x:Type ScrollViewer}"
                   BasedOn="{StaticResource Fluent.Ribbon.Styles.ScrollViewer}" />
        </ResourceDictionary>
    </Application.Resources>
</Application>