stylesheet.css

body{
	width: 800px;
	text-align: center;
	margin: 0 auto; 
}

header{

}

header nav{
	background: black;
	color: white;
	padding: 0;
	height: 40px;
	line-height: 30px;
	border-radius: 5px;
	width: 400px;
	margin-left: auto;
	margin-right: auto;
}

header nav ul{
	list-style: none;
	padding: 0;
	
}

header nav ul li{
	display: inline;
	float: left;
}

header nav a{
	display: inline-block;
	height: 30px;
	width: 100px;
	padding: 5px 0px 5px 0px;
}

header nav .active a{
	background: #cecece;
}

header nav li:first-child a{
	border-top-left-radius: 5px;
	border-bottom-left-radius: 5px;
}

header nav li:last-child a{
	border-top-right-radius: 5px;
	border-bottom-right-radius: 5px;
}