<input type="checkbox" id="cp_navimenuid">
<label class="menu" for="cp_navimenuid">

<div class="menubar">
	<span class="bar"></span>
	<span class="bar"></span>
	<span class="bar"></span>
</div>

<ul>
	<li><a id="home" href="#home">Home</a></li>
	<li><a id="about" href="#about">About</a></li>
	<li><a id="contact" href="#contact">Contact</a></li>
</ul>

</label>

*, *:before, *:after {
	-webkit-box-sizing: border-box;
	        box-sizing: border-box;
}
.menu {
	display: block;
	overflow: hidden;
	width: 60px;
	height: 60px;
	margin: 30px auto;
	cursor: pointer;
	-webkit-transition: all 0.5s ease-in-out;
	        transition: all 0.5s ease-in-out;
	border: 3px solid transparent;
	border-radius: 50%;
	background-color: #1b2538;
}
.menu div.menubar {
	width: 30px;
	margin: 17px auto;
}
.menu div.menubar .bar {
	display: block;
	width: 100%;
	height: 5px;
	margin-top: 3px;
	border-radius: 2px;
	background-color: #ffffff;
}
.menu ul {
	display: none;
	margin: 0;
	padding: 0;
	list-style-type: none;
	-webkit-transition: all 0.5s ease;
	        transition: all 0.5s ease;
	text-align: center;
	opacity: 0;
}
.menu ul li {
	display: inline-block;
}
.menu ul li a {
	display: inline-block;
	padding: 0.7em 0.5em;
	-webkit-transition: all 0.3s ease-in;
	        transition: all 0.3s ease-in;
	text-decoration: none;
	color: #1b2538;
	border-bottom: 4px solid transparent;
	height: 56px;
	line-height: 2em;
}
.menu ul li a:hover {
	color: #ffffff;
	background-color: #1b2538;
}
.menu ul li a:target {
	border-bottom-color: #1b2538;
}
/* クリックした時の動き */
#cp_navimenuid {
	display: none;
}
#cp_navimenuid:checked ~ .menu {
	width: 100%;
	height: 60px;
	border: 3px solid #1b2538;
	border-radius: 5px;
	background-color: transparent;
}
#cp_navimenuid:checked ~ .menu > ul {
	display: block;
	opacity: 1;
}
#cp_navimenuid:checked ~ .menu > .menubar {
	display: none;
}