cfc/cfc-desktop-pet/src/XafPet.Desktop/PetEngine/WebViewHost.xaml

<UserControl x:Class="XafPet.Desktop.PetEngine.WebViewHost"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:wv2="clr-namespace:Microsoft.Web.WebView2.Wpf;assembly=Microsoft.Web.WebView2.Wpf"
             Background="Transparent">
    <Grid>
        <wv2:WebView2 x:Name="PetWebView"
                       DefaultBackgroundColor="Transparent"
                       HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/>
    </Grid>
</UserControl>