Semi.Avalonia/demo/Semi.Avalonia.Demo/Pages/NotificationDemo.axaml

<UserControl
    x:Class="Semi.Avalonia.Demo.Pages.NotificationDemo"
    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"
    d:DesignHeight="450"
    d:DesignWidth="800"
    mc:Ignorable="d">
    <StackPanel HorizontalAlignment="Left" Spacing="20">
        <StackPanel.Styles>
            <Style Selector="Button">
                <Setter Property="Theme" Value="{DynamicResource SolidButton}" />
                <Setter Property="HorizontalAlignment" Value="Stretch" />
            </Style>
        </StackPanel.Styles>

        <Button Click="InfoButton_OnClick" Content="Default" />
        <Button Click="InfoButton_OnClick" Content="Information" />
        <Button Click="InfoButton_OnClick" Content="Success" Classes="Success" />
        <Button Click="InfoButton_OnClick" Content="Warning" Classes="Warning" />
        <Button Click="InfoButton_OnClick" Content="Error" Classes="Danger" />
    </StackPanel>
</UserControl>