--- a/doc/html/logic_programming/rules/index.html
+++ b/doc/html/logic_programming/rules/index.html
@@ -116,7 +116,7 @@
 times, once for each unique combination of matching facts.</p>
 <div class="section" id="backtracking">
 <h3>Backtracking</h3>
-<p>Note that while processing the list of premises within a rule's <tt class="docutils literal"><span class="pre">if</span></tt>
+<p>Note that while processing the list of premises within a rule's <tt class="docutils literal">if</tt>
 clause:</p>
 <ul class="simple">
 <li>If Pyke succeeds at proving a premise:<ul>
@@ -135,13 +135,13 @@
 </ul>
 </li>
 </ul>
-<div align="center" class="figure">
+<div class="figure align-center">
 <img alt="Backtracking Flow Diagram" src="../../images/backtracking.png" />
 <p class="caption">Backtracking Flow Diagram</p>
 </div>
-<p>Thus, execution within each rule's <tt class="docutils literal"><span class="pre">if</span></tt> clause proceeds both backwards and
+<p>Thus, execution within each rule's <tt class="docutils literal">if</tt> clause proceeds both backwards and
 forwards, up and down the list of premises, depending on whether each
-premise succeeds or fails.  The process of backing up within the <tt class="docutils literal"><span class="pre">if</span></tt>
+premise succeeds or fails.  The process of backing up within the <tt class="docutils literal">if</tt>
 clause to try alternate solutions is called <em>backtracking</em>.</p>
 </div>
 </div>