https://stackoverflow.com/questions/17259280/how-do-you-change-background-for-a-button-mouseover-in-wpf
<Window.Resources>
<Style TargetType="{x:Type Button}">
<Setter Property="Background" Value="Red"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Border Background="{TemplateBinding Background}" BorderBrush="Black" BorderThickness="1">
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="Yellow"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>