WordPress/src/main/res/layout/reader_thumbnail_strip.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="?android:selectableItemBackground"
    android:orientation="vertical">

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="@color/reader_divider_grey" />

    <LinearLayout
        android:id="@+id/thumbnail_strip_container"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="@dimen/margin_medium"
        android:layout_marginTop="@dimen/margin_medium"
        android:orientation="horizontal" />

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="@color/reader_divider_grey" />
</LinearLayout>