fedilab-Android-App/app/src/main/res/drawable/border_bottom.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="1dp">

    <item
        android:left="-1dp"
        android:right="-1dp"
        android:top="-1dp"
        android:bottom="1dp">
        <shape
            android:shape="rectangle">
            <stroke
                android:width="1px"
                android:color="@color/mastodonC1__" />
            <solid android:color="@android:color/transparent" />
        </shape>
    </item>

</layer-list>