Good Point! I use Opera 8.52 german on Win XP. With IE everything looks just fine, so it could be a browser issue.
But looking at the html-code of the generated page, I now think there is a problem with the code.
"<p>test</p>" gets rendered to:
-----snip------
<pre class="code html4strict">
<span class="sc2">
<a target="_blank" href="http://december.com/html/4/element/p.html">
<span class="kw2">
<p>
</span>
</a>
test
<span class="sc2">
<span class="kw2">
</p>
</span>
</pre>
--------snap----------
I think bevore </pre>, there are two </span> missing.