WordPress/src/main/res/color/related_posts_preview_header.xml

<?xml version="1.0" encoding="utf-8"?>

<selector
    xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:color="@color/grey"
        android:state_enabled="true" />

    <item
        android:color="@color/grey_lighten_20" />

</selector>