title: Div isn't vivisble in Chrome and Opera
body: <p>I have this html code:</p>
  
  <pre><code>&lt;div id="social"&gt;
                  &lt;div class="barra_gris"&gt;&lt;/div&gt;
                  &lt;div class="caixa_social"&gt;&lt;a class="twitter" href="#" target="_blank"&gt;&lt;img src="img/twitter.png" alt="twitter" /&gt;&lt;/a&gt;
                  &lt;a class="facebook" href="http://www.facebook.com/pages/grup-abs/329596937580" target="_blank"&gt;&lt;img src="img/facebook.png"  /&gt;&lt;/a&gt;                      
                  &lt;/div&gt;
                  &lt;div class="idiomes"&gt;&lt;a href="index.php?s=&lt;? echo $s; ?&gt;&amp;p=&lt;? echo $p; ?&gt;&amp;i=0"&gt;català&lt;/a&gt; | &lt;a href="index.php?s=&lt;? echo $s; ?&gt;&amp;p=&lt;? echo $p; ?&gt;&amp;i=1"&gt;castellano&lt;/a&gt;&lt;/div&gt;
              &lt;/div&gt;
              &lt;div id="logo"&gt;&lt;a href="index.php?s=1&amp;i=&lt;? echo $i; ?&gt;"&gt;&lt;img src="img/logo.png" alt="logo" /&gt;&lt;/a&gt;&lt;/div&gt;
          &lt;/div&gt;
  </code></pre>
  
  <p>And barra_gris has this css:</p>
  
  <pre><code>.barra_gris{
      position:relative;
      width:905px;
      height:15px;
      background-color:#6b6b6b;
      display: block;
  }
  </code></pre>
  
  <p>The problem is that Chrome and Opera doesn't show the <code>barra gris</code> class with this background?</p>
  
  <p>The url of site is: <a href="http://abs.marcmorales.es/" rel="nofollow">http://abs.marcmorales.es/</a></p>
  
  <p>What could the problem be?</p>