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

<Styles xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <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>

  <Styles.Resources>
    <Thickness x:Key="ButtonPadding">8,5,8,6</Thickness>
  </Styles.Resources>
  <Style Selector="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="Padding" Value="{DynamicResource ButtonPadding}" />
    <Setter Property="HorizontalAlignment" Value="Left" />
    <Setter Property="VerticalAlignment" Value="Center" />    
    <Setter Property="FontWeight" Value="Normal" />
    <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
    <Setter Property="Template">
      <ControlTemplate>
        <ContentPresenter x:Name="PART_ContentPresenter"
                          Background="{TemplateBinding Background}"
                          BorderBrush="{TemplateBinding BorderBrush}"
                          BorderThickness="{TemplateBinding BorderThickness}"
                          Content="{TemplateBinding Content}"
                          ContentTemplate="{TemplateBinding ContentTemplate}"
                          Padding="{TemplateBinding Padding}"
                          HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                          VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" />
      </ControlTemplate>
    </Setter>
  </Style>
  
  <Style Selector="ToggleButton /template/ ContentPresenter#PART_ContentPresenter">
    <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
  </Style>

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

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

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

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

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

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

  <Style Selector="ToggleButton:checked:disabled /template/ ContentPresenter#PART_ContentPresenter">
    <Setter Property="Background" Value="{DynamicResource ToggleButtonBackgroundCheckedDisabled}" />
    <Setter Property="BorderBrush" Value="{DynamicResource ToggleButtonBorderBrushCheckedDisabled}" />
    <Setter Property="TextBlock.Foreground" Value="{DynamicResource ToggleButtonForegroundCheckedDisabled}" />
  </Style>

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

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

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

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