.nav {
	position:fixed;
	top:0px;
	left:0px;
	display:flex;
	width:100%;
	height:50px;
	background-color:darkgray;
}
.nav .menu {
	position:relative;
	flex:1;
	text-align:center;
	line-height:50px;
	cursor:pointer;
}
.nav .menu:hover {
	background-color:#0000FF;
	color:white;
}
.nav .menu.active {
	color:white;
}
.nav .bar {
	position:absolute;
	top:0;
	left:0;
	width:16.6666%;
	height:50px;
	background-color:#0000FF;
}
.main .box {
	margin-top:50px;
	width:100%;
	height:800px;
	line-height:400px;
	font-size:36px;
	font-weight:bold;
	color:#0000FF;
	text-align:center;
	border:1px solid black;
}