title: How to access a nested css class
body: <p>I have a nested css class:</p>
  
  <pre><code>.a {
    b.c {
     color: red;
   }
  }
  </code></pre>
  
  <p>How can I access to 'b.c' class?
  I am using <code>&lt;p class="a.b.c"&gt;&lt;/p&gt;</code>, 
  but cannot work.</p>
  
  <p>Thanks.</p>