LanMountainDesktop/LanMountainDesktop.AirAppHost/AirAppWindow.axaml

<faWindowing:FAAppWindow xmlns="https://github.com/avaloniaui"
                         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                         xmlns:faWindowing="using:FluentAvalonia.UI.Windowing"
                         x:Class="LanMountainDesktop.AirAppHost.AirAppWindow"
                         Width="520"
                         Height="360"
                         MinWidth="360"
                         MinHeight="260"
                         WindowStartupLocation="CenterScreen"
                         FontFamily="{DynamicResource AppFontFamily}"
                         Title="Air APP">
    <Grid x:Name="WindowRoot"
          Background="{DynamicResource AirAppWindowBackgroundBrush}">
        <ContentControl x:Name="ContentHost" />
    </Grid>
</faWindowing:FAAppWindow>