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

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="@color/mastodonC1__" />

    <stroke
        android:width="1dp"
        android:color="@color/mastodonC1" />

    <padding
        android:bottom="1dp"
        android:left="1dp"
        android:right="1dp"
        android:top="1dp" />

    <corners
        android:bottomLeftRadius="7dp"
        android:bottomRightRadius="7dp"
        android:topLeftRadius="7dp"
        android:topRightRadius="7dp" />
</shape>