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

nav {
	width: 100px;
}

#extender {
	text-align: right;
}

#extender span {
	font-size: 2em;
	display: inline-block;
}

#extender:hover span {
	transform: rotate(45deg);
}

#main-menu {
	text-align: center;
	overflow: hidden;
	font-size: 1em;
	height: 0;
	transition: height 1s;
}

#extender:hover #main-menu {
	height: 100px;
}

#main-menu li {
	border-left: 1px solid #ddd;
	border-right: 1px solid #ddd;
	border-bottom: 1px solid #ddd;
}

#main-menu li:first-child {
	border-top: 1px solid #ddd;
}