StabilityMatrix/StabilityMatrix.Avalonia/Views/MainWindow.axaml

<windowing:AppWindow xmlns="https://github.com/avaloniaui"
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                     xmlns:vm="using:StabilityMatrix.Avalonia.ViewModels"
                     xmlns:views="using:StabilityMatrix.Avalonia.Views"
                     xmlns:ui="using:FluentAvalonia.UI.Controls"
                     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
                     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
                     xmlns:windowing="clr-namespace:FluentAvalonia.UI.Windowing;assembly=FluentAvalonia"
                     mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
                     x:CompileBindings="True"
                     x:Class="StabilityMatrix.Avalonia.Views.MainWindow"
                     x:DataType="vm:MainWindowViewModel"
                     Icon="/Assets/Icon.ico"
                     Title="StabilityMatrix.Avalonia">

    <Design.DataContext>
        <vm:MainWindowViewModel />
    </Design.DataContext>

    <Grid RowDefinitions="Auto,Auto,*">
        <Grid Name="TitleBarHost"
              ColumnDefinitions="Auto,Auto,*,Auto"
              Height="32"
              Background="Transparent">
            <Image Margin="12 4"
                   IsHitTestVisible="False"
                   Source="/Assets/Icon.ico"
                   Width="18" Height="18"
                   DockPanel.Dock="Left"
                   Name="WindowIcon"
                   RenderOptions.BitmapInterpolationMode="HighQuality">
                <Image.IsVisible>
                    <OnPlatform Default="False">
                        <On Options="Windows" Content="True" />
                    </OnPlatform>
                </Image.IsVisible>
            </Image>

            <TextBlock
                Text="{Binding Title, 
                RelativeSource={RelativeSource FindAncestor, AncestorType=Window}}"
                FontSize="12"
                IsHitTestVisible="False"
                VerticalAlignment="Center"
                Grid.Column="1">
                <TextBlock.IsVisible>
                    <OnPlatform Default="False">
                        <On Options="Windows" Content="True" />
                    </OnPlatform>
                </TextBlock.IsVisible>
            </TextBlock>
            <Border Grid.Column="2" Padding="6" />
        </Grid>
        <ui:NavigationView
            Grid.Row="1"
            Grid.RowSpan="2"
            AlwaysShowHeader="False"
            PaneDisplayMode="Left"
            Content="{Binding CurrentPage}"
            MenuItemsSource="{Binding Pages, Mode=OneWay}"
            SelectedItem="{Binding SelectedCategory}"
            IsSettingsVisible="True"
            IsBackEnabled="True">

            <ui:NavigationView.MenuItemTemplate>
                <DataTemplate DataType="{x:Type vm:PageViewModelBase}">
                    <ui:NavigationViewItem
                        Tag="LaunchPageView"
                        Margin="4,0,0,0"
                        Content="{Binding Title}"
                        IconSource="{Binding Icon}"/>
                </DataTemplate>
            </ui:NavigationView.MenuItemTemplate>
            <ui:NavigationView.DataTemplates>
                <!-- Define your DataTemplates here, could also use ContentTemplate if only 1 template is needed -->
            </ui:NavigationView.DataTemplates>
        </ui:NavigationView>
    </Grid>
</windowing:AppWindow>