How could I use custom style base-on Modern Style?

[Supheria]

Hi, I'm struggling on resolving conflict between my custom styles and Modern Style.

For example, after I adding a custom style of button into App.xaml ResourceDictionary, button style will lost Modern Style and roll back to default wpf style:

--- ResourceDictionary ---
<Style
        TargetType="Button"
        x:Key="PickButtonStyle">
        <Setter Property="Width" Value="50" />
</Style>

--- view ---
<Button
    Style="{StaticResource Settings.PickButtonStyle}" />

I also tried to add BasedOn="{StaticResource {x:Type Button}}" into Style, but is useless.

How could I style Modern Style in custom?

[NotYoojun]

Example:

 <Style x:Key="MyToolboxButton" TargetType="Button" 
-   BasedOn="{StaticResource {x:Type Button}}">
+   BasedOn="{StaticResource {x:Static ui:ThemeKeys.DefaultButtonStyleKey}}">
    <Setter Property="Background" Value="Transparent"/>
    <Setter Property="Margin" Value="2"/>
    <Setter Property="BorderBrush" Value="Transparent"/>
    <Setter Property="BorderThickness" Value="0"/>
    <Setter Property="VerticalAlignment" Value="Stretch"/>
    <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
    <Setter Property="VerticalContentAlignment" Value="Stretch"/>
</Style>

If this helps, please mark it as answer, otherwise just ask.