Avalonia/samples/ControlCatalog/Pages/NavigationPage/NavigationPageStackPage.xaml

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             x:Class="ControlCatalog.Pages.NavigationPageStackPage">
  <DockPanel>
    <ScrollViewer DockPanel.Dock="Right" Width="260">
      <StackPanel Margin="12" Spacing="8">
        <TextBlock Text="Stack Inspector" FontSize="16" FontWeight="SemiBold"
                   Foreground="{DynamicResource SystemControlHighlightAccentBrush}" />

        <Button Content="Push New Page"
                HorizontalAlignment="Stretch"
                Click="OnPush" />
        <Button Content="Insert Before Current"
                HorizontalAlignment="Stretch"
                ToolTip.Tip="Inserts a new page so navigating back from the current page lands on it."
                Click="OnInsert" />

        <Separator />

        <DockPanel>
          <TextBlock DockPanel.Dock="Left" Text="Stack" FontSize="13" FontWeight="SemiBold" />
          <TextBlock x:Name="DepthLabel" DockPanel.Dock="Right"
                     HorizontalAlignment="Right" FontSize="12" Opacity="0.5" />
        </DockPanel>

        <TextBlock Text="▲  Current (top)"
                   FontSize="11" Opacity="0.45" Margin="0,-6,0,0" />

        <StackPanel x:Name="StackDisplay" Spacing="4" Margin="0,4,0,4" />

        <TextBlock Text="▼  Root (bottom)"
                   FontSize="11" Opacity="0.45" Margin="0,4,0,0" />
      </StackPanel>
    </ScrollViewer>

    <Border DockPanel.Dock="Right" Width="1" Background="{DynamicResource SystemControlForegroundBaseMediumLowBrush}" />

    <Border Margin="12"
            BorderBrush="{DynamicResource SystemControlForegroundBaseMediumLowBrush}"
            BorderThickness="1"
            CornerRadius="6"
            ClipToBounds="True">
      <NavigationPage x:Name="DemoNav" />
    </Border>
  </DockPanel>
</UserControl>