title: Unknown property '-moz-box-shadow'. Declaration dropped
body: <p>Suddenly what happened to CSS <code>-moz-box-shadow</code>? In my design the Firefox console appeared with a strange problem:</p>
  
  <p><img src="https://i.stack.imgur.com/6H8xZ.png" alt="Unknown property &#39;-moz-box-shadow&#39;. Declaration dropped."></p>
  
  <p>But as per the <a href="http://css-tricks.com/snippets/css/css-box-shadow/" rel="noreferrer">CSS Box Shadow rules</a> I followed all the rules, then what happened? Here is the block where it's directing:</p>
  
  <pre><code>div.area {
    margin: 2px auto;
    border: 1px solid #ededed;
    -moz-box-shadow: 0 0 2px 0 #ccc;
       -webkit-box-shadow: 0 0 2px 0 #ccc;
       box-shadow: 0 0 2px 0 #ccc;
    margin-top: -80px;
    background-color: #ffffff;
    position: relative;
  }
  </code></pre>
  
  <p>I tried the following too:</p>
  
  <pre><code>div.area {
        -moz-box-shadow: 0 0 2px #ccc;
           -webkit-box-shadow: 0 0 2px #ccc;
           box-shadow: 0 0 2px #ccc;
  }
  </code></pre>
  
  <p>I'm using Mozilla Firefox 20.0.</p>