Avalonia/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/Style1.xaml

<Style xmlns="https://github.com/avaloniaui"
       xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Style.Resources>
    <Color x:Key="Red">Red</Color>
    <Color x:Key="Green">Green</Color>
    <Color x:Key="Blue">Blue</Color>
  </Style.Resources>
</Style>