css triangle for bootstrap left nav

by niki4810

HTML

<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.1/css/bootstrap-combined.min.css">
<ul class="nav nav-stacked nav-tabs">
    <li> <a href="#">Home</a>

    </li>
    <li class="active"><a href="#">About</a>
    </li>
    <li><a href="#">Contact</a>
    </li>
</ul>

CSS

body {
    padding : 50px;
    background-color: #ccc;
}
.nav-tabs > .active > a, .nav-tabs > .active > a:hover {
      color: #ffffff;
  background-color:#1b4860; 
}
.nav > li.active:before{
   content : ""; 
   float:right;
    margin-top :10px;
	width: 0; 
	height: 0; 
	border-top: 10px solid transparent;
	border-bottom: 10px solid transparent ; 	
	border-right:10px solid #fff;     
}