Trigger doesn't change color on hover?

Question

WPF

<Window.Resources>
        <Style TargetType="Button">
            <Setter Property="Foreground" Value="#fff"/>
            <Setter Property="Background" Value="#FF0F4FC5"/>
            <Style.Triggers>
                <Trigger Property="IsMouseOver" Value="True">
                    <Setter Property="Background" Value="#FF00091B" />
                </Trigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>

<Window.Resources>
        <Button Content="Test" Height="100" Margin="18,125,51,138" />

When hovering, it does not change color, as it was standard and remained.
Tell me why you didn't change

Answer 1

Everything looks right. In addition, the style does not have an identifier, and the button does not have a style set. Is it the same in the code or just here in the example?

<Style x:Key="MyStyle" TargetType="Button">
...
<Button Content="Test" Height="100" Margin="18,125,51,138" Style="{StaticResource MyStyle}" />