PlatformInfoPage.xaml

<UserControl x:Class="ControlCatalog.Pages.PlatformInfoPage"
             xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:viewModels="using:ControlCatalog.ViewModels"
             d:DesignHeight="800"
             d:DesignWidth="400"
             mc:Ignorable="d"
             x:DataType="viewModels:PlatformInformationViewModel">
  <StackPanel Spacing="20">
    <TextBlock Text="{Binding PlatformInfo}" />

    <StackPanel TextElement.Foreground="White">
      <StackPanel Orientation="Horizontal">
        <Border Height="100" Width="100" Background="{OnFormFactor Gray, Desktop=Green}">
          <TextBlock Text="Desktop" />
        </Border>
        <Border Height="100" Width="100" Background="{OnFormFactor Gray, Mobile=Green}">
          <TextBlock Text="Mobile" />
        </Border>
        <Border Height="100" Width="100" Background="{OnFormFactor Gray, TV=Green}">
          <TextBlock Text="Tv" />
        </Border>
      </StackPanel>
      <WrapPanel>
        <Border Height="100" Width="100" Background="{OnPlatform Gray, Windows=Green}">
          <TextBlock Text="Windows" />
        </Border>
        <Border Height="100" Width="100" Background="{OnPlatform Gray, macOS=Green}">
          <TextBlock Text="macOS" />
        </Border>
        <Border Height="100" Width="100" Background="{OnPlatform Gray, Linux=Green}">
          <TextBlock Text="Linux" />
        </Border>
        <Border Height="100" Width="100" Background="{OnPlatform Gray, Browser=Green}">
          <TextBlock Text="Browser" />
        </Border>
        <Border Height="100" Width="100" Background="{OnPlatform Gray, iOS=Green}">
          <TextBlock Text="iOS" />
        </Border>
        <Border Height="100" Width="100" Background="{OnPlatform Gray, Android=Green}">
          <TextBlock Text="Android" />
        </Border>
        <Border Height="100" Width="100">
          <Border.Background>
            <OnPlatform Default="Gray" >
              <On Options="macOS, Linux, Windows" Content="Green" />
            </OnPlatform>
          </Border.Background>
          <TextBlock Text="Win, Lin or Mac" />
        </Border>
      </WrapPanel>
    </StackPanel>
  </StackPanel>
</UserControl>