Style definition in xaml

[LauraKami]

Style definition in xaml

[whistyun]

Sorry, I did not take into consideration the use of content and the property element together.
Coulds you please change the xaml to the following?

<!-- xmlns:mdxam="clr-namespace:MdXaml;assembly=MdXaml" -->
<!-- <Grid> -->
<Grid.Resources>
    <Style x:Key="MdStyle" TargetType="FlowDocument">
        <Style.Resources>
            <Style TargetType="Paragraph">
                <Style.Triggers>
                    <Trigger Property="Tag" Value="Heading1">
                        <Setter Property="FontSize"   Value="42" />
                        <Setter Property="Foreground" Value="Red" />
                        <Setter Property="FontWeight" Value="Light" />
                    </Trigger>
                    <Trigger Property="Tag" Value="Heading2">
                        <Setter Property="FontSize"   Value="20" />
                        <Setter Property="Foreground" Value="Blue" />
                        <Setter Property="FontWeight" Value="Light" />
                    </Trigger>
                </Style.Triggers>
            </Style>
        </Style.Resources>
    </Style>

</Grid.Resources>


<mdxam:MarkdownScrollViewer 
    x:Name="MSV"
    Grid.Column="1" Grid.Row="0"
    MarkdownStyle="{StaticResource ResourceKey=MdStyle}"
    xml:space="preserve">
    # Heading 1

    ## Heading 2

    content
</mdxam:MarkdownScrollViewer>
<!-- </Grid> -->

[LauraKami]

Here is the example for newbie like me ;o)
`

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="50*"/>
        <RowDefinition Height="50*"/>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="50*"/>
        <ColumnDefinition Width="50*"/>
    </Grid.ColumnDefinitions>
    <Grid.Resources>
        <Style x:Key="MdStyle" TargetType="FlowDocument">
            <Style.Resources>
                <Style TargetType="Paragraph">
                    <Style.Triggers>
                        <Trigger Property="Tag" Value="Heading1">
                            <Setter Property="FontSize"   Value="42" />
                            <Setter Property="Foreground" Value="Red" />
                            <Setter Property="FontWeight" Value="Light" />
                        </Trigger>
                        <Trigger Property="Tag" Value="Heading2">
                            <Setter Property="FontSize"   Value="20" />
                            <Setter Property="Foreground" Value="Blue" />
                            <Setter Property="FontWeight" Value="Light" />
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </Style.Resources>
        </Style>

    </Grid.Resources>
    <mdxam:MarkdownScrollViewer 
        x:Name="MSV_R0C0"
        Grid.Row="0" Grid.Column="0"
        MarkdownStyle="{StaticResource ResourceKey=MdStyle}"
        xml:space="preserve">
            # Heading R0C0

            ## Heading 2

            content
    </mdxam:MarkdownScrollViewer>

`