title: CSS attribute selector does not work a href
body: <p>I need to use attribute selector in css to change link on different color and image, but it does not work.</p>
  
  <p>I have this html:</p>
  
  <pre><code>&lt;a href="/manual.pdf"&gt;A PDF File&lt;/a&gt;
  </code></pre>
  
  <p>And this css:</p>
  
  <pre><code>a {
       display: block;
       height: 25px;
       padding-left: 25px;
       color:#333;
       font: bold 15px Tahoma;
       text-decoration: none;
   }
   a[href='.pdf'] { background: red; }
  </code></pre>
  
  <p>Why isn't the background red?</p>