Avalonia/src/Avalonia.Themes.Fluent/Controls/ToggleButton.xaml

<ResourceDictionary xmlns="https://github.com/avaloniaui"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    x:ClassModifier="internal">
  <Design.PreviewWith>
    <Border Padding="20">
      <StackPanel Spacing="20">
        <ToggleButton Content="Click Me!" />
        <ToggleButton Content="Disabled" IsEnabled="False" />
        <ToggleButton Content="Three state" IsThreeState="True" />
      </StackPanel>
    </Border>
  </Design.PreviewWith>

  <ControlTheme x:Key="{x:Type ToggleButton}" TargetType="ToggleButton">
    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackground}" />
    <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForeground}" />
    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrush}" />
    <Setter Property="BorderThickness" Value="{DynamicResource ToggleButtonBorderThemeThickness}" />
    <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
    <Setter Property="Padding" Value="{DynamicResource ButtonPadding}" />
    <Setter Property="HorizontalAlignment" Value="Left" />
    <Setter Property="VerticalAlignment" Value="Center" />
    <Setter Property="RenderTransform" Value="none" />
    <Setter Property="Transitions">
      <Transitions>
        <TransformOperationsTransition Property="RenderTransform" Duration="0:0:.075" />
      </Transitions>
    </Setter>

    <Setter Property="Template">
      <ControlTemplate>
        <ContentPresenter x:Name="PART_ContentPresenter"
                          Background="{TemplateBinding Background}"
                          BorderBrush="{TemplateBinding BorderBrush}"
                          BorderThickness="{TemplateBinding BorderThickness}"
                          CornerRadius="{TemplateBinding CornerRadius}"
                          Content="{TemplateBinding Content}"
                          ContentTemplate="{TemplateBinding ContentTemplate}"
                          Padding="{TemplateBinding Padding}"
                          HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                          VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" />
      </ControlTemplate>
    </Setter>

    <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
      <Setter Property="RecognizesAccessKey" Value="True" />
    </Style>

    <Style Selector="^:pointerover /template/ ContentPresenter#PART_ContentPresenter">
      <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundPointerOver}" />
      <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushPointerOver}" />
      <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundPointerOver}" />
    </Style>

    <Style Selector="^:pressed">
      <Setter Property="RenderTransform" Value="scale(0.98)" />
    </Style>

    <Style Selector="^:pressed /template/ ContentPresenter#PART_ContentPresenter">
      <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundPressed}" />
      <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushPressed}" />
      <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundPressed}" />
    </Style>

    <Style Selector="^:disabled /template/ ContentPresenter#PART_ContentPresenter">
      <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundDisabled}" />
      <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushDisabled}" />
      <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundDisabled}" />
    </Style>

    <Style Selector="^:indeterminate">
      <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
        <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminate}" />
        <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminate}" />
        <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminate}" />
      </Style>

      <Style Selector="^:pointerover /template/ ContentPresenter#PART_ContentPresenter">
        <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminatePointerOver}" />
        <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminatePointerOver}" />
        <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminatePointerOver}" />
      </Style>

      <Style Selector="^:pressed /template/ ContentPresenter#PART_ContentPresenter">
        <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminatePressed}" />
        <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminatePressed}" />
        <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminatePressed}" />
      </Style>

      <Style Selector="^:disabled /template/ ContentPresenter#PART_ContentPresenter">
        <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundIndeterminateDisabled}" />
        <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushIndeterminateDisabled}" />
        <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundIndeterminateDisabled}" />
      </Style>
    </Style>

    <Style Selector="^:checked">
      <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
        <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundChecked}" />
        <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushChecked}" />
        <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundChecked}" />
      </Style>

      <Style Selector="^:pointerover /template/ ContentPresenter#PART_ContentPresenter">
        <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundCheckedPointerOver}" />
        <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushCheckedPointerOver}" />
        <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundCheckedPointerOver}" />
      </Style>

      <Style Selector="^:pressed /template/ ContentPresenter#PART_ContentPresenter">
        <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundCheckedPressed}" />
        <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushCheckedPressed}" />
        <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundCheckedPressed}" />
      </Style>

      <Style Selector="^:disabled /template/ ContentPresenter#PART_ContentPresenter">
        <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundCheckedDisabled}" />
        <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushCheckedDisabled}" />
        <Setter Property="Foreground" Value="{DynamicResource ToggleButtonForegroundCheckedDisabled}" />
      </Style>
    </Style>
  </ControlTheme>
</ResourceDictionary>