.portfolio-grid {
	float:left;
	position:relative;
	z-index:1;
	display: block;
	width:990px;
	margin-top: 0px;
	margin-right: auto;
	margin-bottom: 0px;
	margin-left: auto;
	display:inline-block;
}

.portfolio-grid:after,
.portfolio-item:before {
	content: '';
    display: table;
}

.portfolio-grid:after {
	clear: both;
}

.portfolio-grid li {
	width: 220px;
	height: 220px;
	display: inline-block;
	margin-right:20px;
	margin-bottom:20px;

}