Someone

body {
	background: black;
}

.cadretop {
	width: 500px;
	height: 50px;
	border: 2px solid red;
	background-color: blue;
}

.cadreleft {
	float: left;
	margin-top: 5px;
	width: 200px;
	height: 500px;
	border: 2px solid green;
	background-color:#0070f0;
}

.cadrecontenu {
	margin-top: 5px;
	margin-left: 210px;
	height: 800px;
	width: 450px;
	border: 2px solid green;
	background-color:#0070f0;
}