Expanding Search Bar/Box CSS only (no JS)

main.css

/* Free to use for everyone */
/* Example: http://codepen.io/elwint/pen/vGMRaB */

body {
	font-family: sans-serif;
	background-color: #111;
}

.button {
	display: inline-block;
	margin: 4px 2px;
	background-color: #444;
	font-size: 14px;
	padding-left: 32px;
	padding-right: 32px;
	height: 50px;
	line-height: 50px;
	text-align: center;
	color: white;
	text-decoration: none;
	cursor: pointer;
	-moz-user-select: none;
	-khtml-user-select: none;
	-webkit-user-select: none;
	-ms-user-select: none;
	user-select: none;
}

.button:hover {
	transition-duration: 0.4s;
	-moz-transition-duration: 0.4s;
	-webkit-transition-duration: 0.4s;
	-o-transition-duration: 0.4s;
	background-color: white;
	color: black;
}

.search-container {
	position: relative;
	display: inline-block;
	margin: 4px 2px;
	height: 50px;
	width: 50px;
	vertical-align: bottom;
}

.mglass {
	display: inline-block;
	pointer-events: none;
	-webkit-transform: rotate(-45deg);
	-moz-transform: rotate(-45deg);
	-o-transform: rotate(-45deg);
	-ms-transform: rotate(-45deg);
}

.searchbutton {
	position: absolute;
	font-size: 22px;
	width: 100%;
	margin: 0;
	padding: 0;
}

.search:focus + .searchbutton {
	transition-duration: 0.4s;
	-moz-transition-duration: 0.4s;
	-webkit-transition-duration: 0.4s;
	-o-transition-duration: 0.4s;
	background-color: white;
	color: black;
}

.search {
	position: absolute;
	left: 49px; /* Button width-1px (Not 50px/100% because that will sometimes show a 1px line between the search box and button) */
	background-color: white;
	outline: none;
	border: none;
	padding: 0;
	width: 0;
	height: 100%;
	z-index: 10;
	transition-duration: 0.4s;
	-moz-transition-duration: 0.4s;
	-webkit-transition-duration: 0.4s;
	-o-transition-duration: 0.4s;
}

.search:focus {
	width: 363px; /* Bar width+1px */
	padding: 0 16px 0 0;
}

.expandright {
	left: auto;
	right: 49px; /* Button width-1px */
}

.expandright:focus {
	padding: 0 0 0 16px;
}

An example with html can be found here: http://codepen.io/elwint/pen/vGMRaB