vertically and horizontally fontawesome icon inside a div

by ravimallya

HTML

<link rel="stylesheet" href="//netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/css/bootstrap-combined.no-icons.min.css">
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/font-awesome/3.2.1/css/font-awesome.css">
<div class="container how-it-works">
    <div class="row">
        <div class="span3">
            <div class="symbol-outer">
                <div class="symbol-holder"> 
                    <i class="icon-envelope"></i>

                </div>
            </div>
        </div>
        <div class="span9">
           
        </div>
    </div>
</div>

CSS

.how-it-works .symbol-outer {
  display: table;
width: 100%;
    background:#999;
    text-align:center;
}
.how-it-works .symbol-outer .symbol-holder {
    font-size: 10em;
        height:200px;
    display:table-cell;
    vertical-align:middle;
  
   
}