nextcloud-android/res/values/versioned_styles.xml

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:android="http://schemas.android.com/apk/res/android">
	
    <!-- Buttons -->
	<style name="Theme.ownCloud.ButtonStyle" parent="@android:style/Widget.Button">
		<item name="android:background">@android:drawable/btn_default</item>
		<item name="android:textColor">@color/button_text_color</item>
	</style>
	
	<!-- DropDown -->
	<style name="Theme.ownCloud.DropDownStyle"
		parent="style/Widget.AppCompat.Spinner.DropDown.ActionBar">
		<!--<item name="android:background">@drawable/spinner_inner</item>-->
	</style>
	
	<style name="Theme.ownCloud.IndeterminateStyle"
		parent="style/Widget.AppCompat.ProgressBar">
	    <!--<item name="android:indeterminateDrawable">@drawable/abs__progress_medium_holo</item>-->
	</style>

	<!-- Notifications -->
	<style 	name="Theme.ownCloud.NotificationText.Title" 
	    	parent="@android:style/TextAppearance">
        <item name="android:textColor">#ff000000</item>
		<item name="android:textSize">18sp</item>
        <item name="android:textStyle">bold</item>
	</style>
	<style 	name="Theme.ownCloud.NotificationText.Content" 
	    	parent="@android:style/TextAppearance">
        <item name="android:textColor">#ff000000</item>
		<item name="android:textSize">14sp</item>
	</style>
</resources>