Avalonia/src/Avalonia.Themes.Default/NotificationCard.xaml

<Styles xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Style Selector="NotificationCard">
        <Setter Property="UseLayoutRounding" Value="True"/>
        <Setter Property="Width" Value="350"/>
        <Setter Property="FontSize" Value="14"/>
        <Setter Property="Foreground" Value="White"/>
        <Setter Property="RenderTransformOrigin" Value="50%,75%"/>
        <Setter Property="Template">
            <ControlTemplate>
                <LayoutTransformControl Name="PART_LayoutTransformControl" UseRenderTransform="True">
                    <Border Background="{TemplateBinding Background}" 
                            BorderBrush="{TemplateBinding BorderBrush}" 
                            BorderThickness="{TemplateBinding BorderThickness}"
                            Margin="8,8,0,0">
                        <ContentControl Name="PART_Content" Content="{TemplateBinding Content}" />
                    </Border>
                </LayoutTransformControl>
            </ControlTemplate>
        </Setter>

        <Style.Animations>
            <Animation Duration="0:0:0.45" Easing="QuadraticEaseIn" FillMode="Forward">
                <KeyFrame Cue="0%">
                    <Setter Property="Opacity" Value="0"/>
                    <Setter Property="TranslateTransform.Y" Value="20"/>
                    <Setter Property="ScaleTransform.ScaleX" Value="0.85"/>
                    <Setter Property="ScaleTransform.ScaleY" Value="0.85"/>
                </KeyFrame>
                <KeyFrame Cue="30%">
                    <Setter Property="TranslateTransform.Y" Value="-20"/>
                </KeyFrame>
                <KeyFrame Cue="100%">
                    <Setter Property="Opacity" Value="1"/>
                    <Setter Property="TranslateTransform.Y" Value="0"/>
                    <Setter Property="ScaleTransform.ScaleX" Value="1"/>
                    <Setter Property="ScaleTransform.ScaleY" Value="1"/>
                </KeyFrame>
            </Animation>
        </Style.Animations>
    </Style>

    <Style Selector="NotificationCard/template/ ContentControl#PART_Content">
        <Setter Property="MinHeight" Value="150" />
    </Style>

    <Style Selector="NotificationCard[IsClosing=true] /template/ LayoutTransformControl#PART_LayoutTransformControl">
        <Setter Property="RenderTransformOrigin" Value="50%,0%"/>
        <Style.Animations>
            <Animation Duration="0:0:0.75" Easing="QuadraticEaseOut" FillMode="Forward">
                <KeyFrame Cue="0%">
                    <Setter Property="TranslateTransform.X" Value="0"/>
                    <Setter Property="ScaleTransform.ScaleY" Value="1"/>
                </KeyFrame>
                <KeyFrame Cue="70%">
                    <Setter Property="TranslateTransform.X" Value="800"/>
                    <Setter Property="ScaleTransform.ScaleY" Value="1"/>
                </KeyFrame>
                <KeyFrame Cue="100%">
                    <Setter Property="ScaleTransform.ScaleY" Value="0"/>
                    <Setter Property="TranslateTransform.X" Value="800"/>
                </KeyFrame>
            </Animation>
        </Style.Animations>
    </Style>

    <Style Selector="NotificationCard[IsClosing=true]">
        <Style.Animations>
            <Animation Duration="0:0:1.25" Easing="QuadraticEaseOut" FillMode="Forward">
                <KeyFrame Cue="100%">
                    <Setter Property="IsClosed" Value="True"/>
                </KeyFrame>
            </Animation>
        </Style.Animations>
    </Style>

    <Style Selector="NotificationCard">
        <Setter Property="Background" Value="{DynamicResource NotificationCardBackgroundBrush}"/>
    </Style>
    <Style Selector="NotificationCard:information">
        <Setter Property="Background" Value="{DynamicResource NotificationCardInformationBackgroundBrush}"/>
    </Style>
    <Style Selector="NotificationCard:success">
        <Setter Property="Background" Value="{DynamicResource NotificationCardSuccessBackgroundBrush}"/>
    </Style>
    <Style Selector="NotificationCard:warning">
        <Setter Property="Background" Value="{DynamicResource NotificationCardWarningBackgroundBrush}"/>
    </Style>
    <Style Selector="NotificationCard:error">
        <Setter Property="Background" Value="{DynamicResource NotificationCardErrorBackgroundBrush}"/>
    </Style>
</Styles>