flat button

    <Button
        android:theme="@style/Shop.Button.Light"
        android:id="@+id/buy_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textColor="?attr/shopButtonTextColor"
        style="?attr/buttonStyle"
        android:stateListAnimator="@null"
        android:textStyle="bold"
        android:text="@string/shop_buy" />
    
    <style name="Shop.Button.Light" parent="@style/Theme.JStock.Light">
        <item name="colorButtonNormal">@color/shop_button_background_color_material_light</item>
        <item name="android:colorButtonNormal">@color/shop_button_background_color_material_light</item>
        <item name="colorControlHighlight">#ffffffff</item>
        <item name="android:colorControlHighlight">#ffffffff</item>
    </style>