*{
	margin: 0;
	padding: 0;
	-webkit-box-sizing: border-box;
	-moz-box-sizing: border-box;
	box-sizing: border-box;
}

body{
	font-family: Arial, Sans-serif;
	font-size: 16px;
	background-color: #4a465b
}
header{background-color: #ffffff}

header nav {width: 100%;}

header nav ul{
	width: 100%;
	overflow: hidden;
	list-style: none;
}

header nav ul li{
	float: left;
	/* display: inline-block; */
}

header nav ul li a{
	text-decoration: none;
	display: inline-block;
	padding: 15px 20px;
	color: #000000;
}

header nav ul li a:hover{
	background:#000000;
    color: #ffffff;
}

.cajacontenedor{
	width: 1000px;
	margin: 20px auto;
}

footer{
	width: 100%; /* -poner en porcentaje el width del footer 100%--*/
	clear: both;
	background: #000000;
	color: #ffffff;
	padding: 15px 0px;
	text-align: center;
}

.cuerpo{
	padding: 20px;
	
}

section img{
	margin: 7px;
	opacity: 0.37;
	border:3px solid #ffffff;
}

section img:hover{
	opacity: 1;
	border:3px solid #F56C29;
}