sourcegit/src/Resources/Styles/IconButton.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:controls="clr-namespace:SourceGit.Views.Controls">
    <Style TargetType="{x:Type controls:IconButton}">
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="Foreground" Value="{DynamicResource Brush.FG1}"/>
        <Setter Property="BorderBrush" Value="Transparent"/>
        <Setter Property="BorderThickness" Value="0"/>
        <Setter Property="Opacity" Value=".8"/>
        <Setter Property="Padding" Value="0"/>
        <Setter Property="SnapsToDevicePixels" Value="True"/>

        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type controls:IconButton}">
                    <Border
                        x:Name="Border"
                        BorderBrush="{TemplateBinding BorderBrush}" 
                        BorderThickness="{TemplateBinding BorderThickness}" 
                        Background="{TemplateBinding Background}"
                        Padding="{TemplateBinding Padding}">
                        <Path
                            Fill="{TemplateBinding Foreground}"
                            Data="{TemplateBinding Icon}"/>
                    </Border>

                    <ControlTemplate.Triggers>
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter TargetName="Border" Property="Background" Value="{Binding HoverBackground, RelativeSource={RelativeSource AncestorType={x:Type controls:IconButton}}}"/>
                            <Setter Property="Opacity" Value="1"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>

        <Style.Triggers>
            <Trigger Property="IsMouseOver" Value="True">
                <Setter Property="Opacity" Value="1"/>
            </Trigger>
        </Style.Triggers>
    </Style>
</ResourceDictionary>