title: css3 pure: how to hover an element outside?
body: <pre><code>div.test:hover #sendBtn{
      color:red;
  }
  </code></pre>
  
  <p>This works fine is sendBtn is INSIDE the div.test element</p>
  
  <p>But how to achieve this (pure CSS) when it is outside ?
  ex: </p>
  
  <pre><code>&lt;button id="sendBtn"&gt;hello&lt;/button&gt;
  &lt;div class='test'&gt;div here&lt;/div&gt;
  </code></pre>