Heading sizes in demo are incorrect

[ghareth]

The headings applied in the demo do not correspond to headings they claim to be.

<div class="section" id="Headings">
<h2>Headings<a class="headerlink" href="#Headings" title="Permalink to this headline">¶</a></h2>
<p>This is a first level heading (<code class="docutils literal"><span class="pre">h1</span></code>).</p>
<div class="section" id="Sub-Heading">
<h3>Sub-Heading<a class="headerlink" href="#Sub-Heading" title="Permalink to this headline">¶</a></h3>
<p>This is a second level heading (<code class="docutils literal"><span class="pre">h2</span></code>).</p>
<div class="section" id="Sub-Sub-Heading">
<h4>Sub-Sub-Heading<a class="headerlink" href="#Sub-Sub-Heading" title="Permalink to this headline">¶</a></h4>
<p>This is a third level heading (<code class="docutils literal"><span class="pre">h3</span></code>).</p>
</div>