.sert{
	text-align:center; 
	width:100%;
	margin:0 auto 20px auto;
	overflow:hidden;
}
.sert .item{
	display:inline-block;
	margin-left:30px;
}
.sert img{
	

}

@media (max-width: 960px) {
	.sert .item{
		margin-left:10px;
		width:25% !important;
	}
	.sert img{
		width:100% !important;
	}
}