body * {
	box-sizing: border-box;
}
.container {
	width: 980px;
	margin: 0 auto;
}
#contenido {
	margin-bottom: 100px;
}
.box-anuncio {
	float: left;
	width: 24%;
	text-align: center;
	padding: 25px;
	border: 3px solid #b1b1b1;
	padding: 20px;
	background-color: #f7f7f7;
	border-radius: 10px;
	margin: 0 0.5%;
}
.box-anuncio img {
	width: 150px;
}