Edit in JSFiddle

<ul>
   <li><a href="#">Home</a></li>
    <li><a href="#">Page 2</a></li>
    <li><a href="#">Page 3</a></li>
    <li><a href="#">Page 4</a></li>
    <li><a href="#">Some Other Page</a></li>
</ul>
ul { margin-top: 10px;}
ul li {
   border-bottom: 28px solid #c50723;
   border-left: 28px solid transparent;
   border-right: 28px solid transparent;
   height: 0;
   display: inline-block;
   margin: 0 -35px 0 0;
   padding: 0;
}
ul li:hover { border-bottom: 28px solid #f98a4e; }
ul li a {
	color: #fff;
	display: block;
	float: left;
	margin: 0;
	padding: 5px;
	text-decoration: none;
}