How do you disable MouseOver effects on a Button in WPF?

I'm trying to disable the MouseOver effect on buttons, or at least change the colour of it, in WPF.

I'm using the following style:

<Style x:Key="Borderless" TargetType="{x:Type Button}">
            <Setter Property="OverridesDefaultStyle" Value="True"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type Button}">
                        <Button Background="{TemplateBinding Control.Background}"
                                Focusable="False">
                            <ContentPresenter
                  Margin="{TemplateBinding Control.Padding}"
                  HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
                  VerticalAlignment="{TemplateBinding Control.VerticalContentAlignment}"
                  SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}"
                  ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}"
                  RecognizesAccessKey="True"
                  Content="{TemplateBinding ContentControl.Content}" />
                            </Button>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

in Window.Resources, which I thought would override all the default behaviours. But it doesn't.

Any suggestions?