Applying button style, works right on AndroidStudio preview, but doesn't work on device

I've define a Style for the button

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="android:fontFamily">sans-serif</item>
    <item name="android:windowBackground">@color/background</item>
    <item name="android:buttonStyle">@style/AppTheme.Button</item>
    <item name="android:textViewStyle">@style/AppTheme.TextView</item>
    <item name="android:editTextStyle">@style/AppTheme.EditText</item>
    <item name="android:checkboxStyle">@style/AppTheme.CheckBox</item>
</style>

button style:

<style name="AppTheme.Button" parent="android:Widget.Button">
    <item name="android:background">@drawable/button_background</item>
    <item name="android:textColor">@color/white</item>
    <item name="android:textSize">@dimen/normal_text</item>
</style>

I can see it properly on the Android Studio preview, but doesn't work on device. It works on device if I set it in the element inside the layout.

            <Button
                android:id="@+id/btn_login"
                style="@style/AppTheme.Button"
                android:layout_height="wrap_content"
                android:layout_width="wrap_content"
                android:text="LOGIN"/>

I just want to define it in the AppTheme