example of using intent to capture some CSS customization for AT

src/intent.html

@@ -562,6 +562,28 @@ <h3 id="mixing_intent_examples">Intent Examples</h3>
 <blockquote>bell number of 2</blockquote>
 </div>
 
+<p>CSS customization is generally not made available
+  to AT. In cases where authors have meaningful stylistic emphases, 
+  or stylized constructs with custom names, using an intent attribute is appropriate. 
+  A pedagogical example would be:</p>
+<div class="example mathml mmlcore">
+<pre>
+&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;
+&lt;mrow style="padding:0.1em;background-color:lightyellow;"
+      intent="highlighted-step($step)"&gt;
+  &lt;mfrac arg="step"&gt;&lt;mn&gt;6&lt;/mn&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mfrac&gt;
+&lt;/mrow&gt;
+&lt;mi&gt;x&lt;/mi&gt;
+&lt;mo&gt;=&lt;/mo&gt;
+&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;
+&lt;mn style="padding:0.1em;background-color:lightgreen;"
+    intent="highlighted-result(3)"&gt;3&lt;/mn&gt;
+&lt;mi&gt;x&lt;/mi&gt;
+</pre>
+<blockquote>one plus highlighted step of six over two end highlighted step x
+  equals one plus highlighted result of three end highlighted result x
+</blockquote>
+</div>
 
 <section>
  <h4 id="mixing_intent_examples_mtr">Tables</h4>