<doc>
  <section1>
    <heading>A Level-1 Heading</heading>
    <para>The first paragraph.</para>
    <para>The second paragraph.</para>
    <section2>
      <heading>A Level-2 Heading</heading>
      <para>The first paragraph after the sub-heading.</para>
    </section2>
  </section1>
</doc>

