title: Apply style if element exists
body: <p>I need to use CSS to apply style to class <strong>article</strong> ONLY if class <strong>subject</strong> is present inside <strong>.container</strong></p>
  
  <pre><code>&lt;div class="container"&gt;
      &lt;div class="subject"&gt;
         ...
      &lt;/div&gt;
      &lt;div class="article"&gt;
         ...
      &lt;/div&gt;    
  &lt;/div&gt;
  </code></pre>
  
  <p>I was trying to use sibling selector, but it does not seem to work. What am I missing?</p>
  
  <pre><code>.container + .subject .article { ... }
  </code></pre>