session-android/res/drawable/pn_option_background_selected.xml

<?xml version="1.0" encoding="utf-8"?>
<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle" >

    <solid
        android:color="@color/pn_option_background" />

    <stroke
        android:color="@color/accent"
        android:width="@dimen/border_thickness" />

    <corners android:radius="@dimen/pn_option_corner_radius" />

</shape>