html, body {
	margin: 0px;
	padding: 0px;
	height: 100%;
	width: 100%;
}
.caja1 {
	height: 100%;
	width: 50%;
	background-color: green;
	float: RIGHT;
}
.caja2 {
	height: 50%;
	width: 50%;
	background-color: #FFFFFF;
	position: relative;
	float: left;
}

.caja3 {
	height: 50%;
	width: 50%;
	float: left;
	background-color: 	#00FFCC	;
}