.container_port{
	width: 100%;
	float:left;
	margin:50px 0 30px 0;
}
.gallery {
	list-style: none;
	overflow: hidden;
	padding: 0;
	margin: 0;
}
.gallery li {
	float: left;
	width:33.3%;
	margin-bottom:0;
}
.gallery li img {
	width:100%;
	height:auto;
	display:block;
}
@media only screen and ( max-width : 480px ) {

.gallery li {
	float: left;
	width:50%;
	margin-bottom:0;
}