How to leave a certain distance between the right page content of the NavigationView and the Titlebar

Hello @studio XFE ,

Welcome to Microsoft Q&A!

According to the code in the WinUI3 Template Project, it is achieved by customizing the title bar. You can refer to the following code.

<Grid>
     <Grid.RowDefinitions>
         <RowDefinition Height="Auto"/>
         <RowDefinition/>
     </Grid.RowDefinitions>
     <Grid x:Name="AppTitleBar"
   Height="48">
         <Grid.ColumnDefinitions>
             <ColumnDefinition x:Name="LeftPaddingColumn" Width="0"/>
             <ColumnDefinition x:Name="IconColumn" Width="Auto"/>
             <ColumnDefinition x:Name="TitleColumn" Width="Auto"/>
         </Grid.ColumnDefinitions>
         <Image x:Name="TitleBarIcon" 
        Source="ms-appx:///Assets/WindowIcon.ico"
        Grid.Column="1"
        Width="16" Height="16"
        Margin="8,0,4,0"/>
         <TextBlock x:Name="TitleBarTextBlock"
                    Text="App title" 
                    Style="{StaticResource CaptionTextBlockStyle}"
                    Grid.Column="2"
                    VerticalAlignment="Center">
         </TextBlock>
     </Grid>
     
     <NavigationView
     Grid.Row="1"
     x:Name="NavigationViewControl"    
     IsBackButtonVisible="Visible"
     IsSettingsVisible="False"
     Header="Main">
         <NavigationView.MenuItems>
             <NavigationViewItem Content="Nav Item A"/>
             <NavigationViewItem Content="Nav Item B"/>
             <NavigationViewItem Content="Nav Item C"/>
         </NavigationView.MenuItems>
         <Grid>
             <Frame x:Name="ContentFrame" />
         </Grid>
     </NavigationView>
     
 </Grid>

 public MainWindow()
 {
     this.InitializeComponent();
     this.ExtendsContentIntoTitleBar = true;
     this.SetTitleBar(AppTitleBar);
 }

Thank you.

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