bloxstrap/Bloxstrap/UI/Style/Default.xaml

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:ui="http://schemas.lepo.co/wpfui/2022/xaml">

    <!--  Taken from DefaultUiCardExpanderStyle  -->
    <Style x:Key="NoUserExpansionCardExpanderStyle" TargetType="{x:Type ui:CardExpander}">
        <!--  Universal WPF UI focus  -->
        <Setter Property="FocusVisualStyle" Value="{DynamicResource DefaultControlFocusVisualStyle}" />
        <!--  Universal WPF UI focus  -->
        <Setter Property="Background">
            <Setter.Value>
                <SolidColorBrush Color="{DynamicResource ControlFillColorDefault}" />
            </Setter.Value>
        </Setter>
        <Setter Property="Foreground">
            <Setter.Value>
                <SolidColorBrush Color="{DynamicResource TextFillColorPrimary}" />
            </Setter.Value>
        </Setter>
        <Setter Property="IconForeground">
            <Setter.Value>
                <SolidColorBrush Color="{DynamicResource TextFillColorPrimary}" />
            </Setter.Value>
        </Setter>
        <Setter Property="BorderBrush" Value="{DynamicResource ControlElevationBorderBrush}" />
        <Setter Property="BorderThickness" Value="{StaticResource CardExpanderBorderThemeThickness}" />
        <Setter Property="Padding" Value="{StaticResource CardExpanderPadding}" />
        <Setter Property="HorizontalAlignment" Value="Stretch" />
        <Setter Property="VerticalAlignment" Value="Center" />
        <Setter Property="HorizontalContentAlignment" Value="Stretch" />
        <Setter Property="VerticalContentAlignment" Value="Center" />
        <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
        <Setter Property="FontWeight" Value="Normal" />
        <Setter Property="Border.CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
        <Setter Property="IconFilled" Value="False" />
        <Setter Property="Icon" Value="Empty" />
        <Setter Property="IsExpanded" Value="False" />
        <Setter Property="SnapsToDevicePixels" Value="True" />
        <Setter Property="OverridesDefaultStyle" Value="True" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ui:CardExpander}">
                    <!--  Top level border should not have padding or margin  -->
                    <Border
                        x:Name="ContentBorder"
                        Width="{TemplateBinding Width}"
                        Height="{TemplateBinding Height}"
                        MinWidth="{TemplateBinding MinWidth}"
                        MinHeight="{TemplateBinding MinHeight}"
                        Padding="0"
                        HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
                        VerticalAlignment="{TemplateBinding VerticalAlignment}"
                        Background="{TemplateBinding Background}"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}"
                        CornerRadius="{TemplateBinding Border.CornerRadius}">
                        <Grid>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto" />
                                <RowDefinition Height="Auto" />
                            </Grid.RowDefinitions>

                            <!--  Top level controls always visible  -->
                            <Grid
                                Margin="{TemplateBinding Padding}"
                                HorizontalAlignment="Stretch"
                                VerticalAlignment="Center"
                                Background="Transparent">
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="Auto" />
                                    <ColumnDefinition Width="*" />
                                </Grid.ColumnDefinitions>
                                <ContentPresenter
                                    x:Name="HeaderContentPresenter"
                                    Grid.Column="1"
                                    Content="{TemplateBinding Header}"
                                    TextElement.Foreground="{TemplateBinding Foreground}" />
                            </Grid>

                            <!--  Collapsed content to expand  -->
                            <Border
                                x:Name="ContentPresenterBorder"
                                Grid.Row="1"
                                Background="Transparent"
                                BorderBrush="{TemplateBinding BorderBrush}"
                                Opacity="0.0">
                                <ContentPresenter
                                    x:Name="ContentPresenter"
                                    Margin="{TemplateBinding Padding}"
                                    HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                                    VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                                    Content="{TemplateBinding Content}" />
                                <Border.LayoutTransform>
                                    <ScaleTransform ScaleY="0" />
                                </Border.LayoutTransform>
                            </Border>
                        </Grid>
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsExpanded" Value="True">
                            <Setter TargetName="ContentPresenterBorder" Property="BorderThickness" Value="0,1,0,0" />
                            <Trigger.EnterActions>
                                <BeginStoryboard>
                                    <Storyboard>
                                        <DoubleAnimation
                                            Storyboard.TargetName="ContentPresenterBorder"
                                            Storyboard.TargetProperty="(Border.LayoutTransform).(ScaleTransform.ScaleY)"
                                            From="0.0"
                                            To="1.0"
                                            Duration="00:00:00.167" />
                                        <DoubleAnimation
                                            Storyboard.TargetName="ContentPresenterBorder"
                                            Storyboard.TargetProperty="(Border.Opacity)"
                                            From="0.0"
                                            To="1.0"
                                            Duration="00:00:00.167" />
                                    </Storyboard>
                                </BeginStoryboard>
                            </Trigger.EnterActions>
                            <Trigger.ExitActions>
                                <BeginStoryboard>
                                    <Storyboard>
                                        <DoubleAnimation
                                            Storyboard.TargetName="ContentPresenterBorder"
                                            Storyboard.TargetProperty="(Border.LayoutTransform).(ScaleTransform.ScaleY)"
                                            From="1.0"
                                            To="0"
                                            Duration="00:00:00.167" />
                                        <DoubleAnimation
                                            Storyboard.TargetName="ContentPresenterBorder"
                                            Storyboard.TargetProperty="(Border.Opacity)"
                                            From="1.0"
                                            To="0.0"
                                            Duration="00:00:00.167" />
                                    </Storyboard>
                                </BeginStoryboard>
                            </Trigger.ExitActions>
                        </Trigger>
                        <Trigger Property="IsMouseOver" Value="True">
                            <!--<Setter Property="Background" Value="{DynamicResource ControlFillColorSecondaryBrush}" />-->
                        </Trigger>
                        <Trigger Property="IsEnabled" Value="False">
                            <Setter Property="Background" Value="{DynamicResource ControlFillColorDisabledBrush}" />
                            <Setter Property="BorderBrush" Value="{DynamicResource ControlStrokeColorDefaultBrush}" />
                            <Setter TargetName="ContentPresenter" Property="TextElement.Foreground" Value="{DynamicResource TextFillColorDisabledBrush}" />
                            <Setter TargetName="HeaderContentPresenter" Property="TextElement.Foreground" Value="{DynamicResource TextFillColorDisabledBrush}" />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>