title: Class vs ID with nested CSS
body: <p>Suppose a HTML like this:</p>
  
  <pre><code>&lt;div id="header"&gt;
    &lt;span class="title"&gt;Title&lt;/span&gt;
    &lt;!-- more spans and other things here --&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>This would work together with a nested CSS:</p>
  
  <pre><code>#header .title { /* CSS */ }
  </code></pre>
  
  <p>This works of course, but I don't like the usage of <code>class</code> here. As I need the style <code>title</code> only once, I would like to use an id. But then the name would have to be something like <code>header_title</code> (since I might have other titles in the HTML), resulting in a CSS</p>
  
  <pre><code>#header #header_title { /* CSS */ }
  </code></pre>
  
  <p>Now this seems to defeat the purpose of nested CSS, then I could just drop the first <code>#header</code> completely.</p>
  
  <p>I can't really figure out a way to do this "right". Am I missing something, or do I just have to live with some "dirty" code here?</p>