.container-nav-img li:nth-child(4) {
    background: rgba(0,0,0,0.7);
    border-radius: 20px;
}

.ad {
    padding-top:30px;
    text-align: center
}

.ad .title {
    font-size: 30px;
    height: 50px;
    line-height: 50px;
    font-weight: 400;
    color: #31475e
}

.case {
	padding: 50px 0
}

.case .tab {
	margin-bottom: 40px;
	height: 30px;
	line-height: 30px;
	overflow: hidden
}

.case .tab li {
	float: left;
	padding: 0 24px;
	margin-right: 10px;
	font-size: 14px;
	cursor: pointer
}

.case .tab li:hover {
	color: #00d1a0
}

.case .tab li.active {
	background: #00d1a0;
	color: #fff;
	border-radius: 30px
}

.case .list ul {
	width: 1200px;
	margin-left: -20px;
	margin-right: -20px
}

.case .list ul li {
	position: relative;
	float: left;
	margin-left: 20px;
	margin-bottom: 20px;
	width: 370px;
	height: 430px;
	box-shadow: 0 3px 15px 0 rgba(224,224,224,.5);
	border: 1px solid #f0f3f7;
	overflow: hidden
}

.case .list ul li:hover {
	box-shadow: 0 6px 15px #ddd
}

.case .list ul li:hover .pic:after {
	background: rgba(0,0,0,.4)
}

.case .list ul li:hover .pic .logo {
	opacity: 1;
	filter: alpha(opacity=100)
}

.case .list ul li .pic {
	position: relative;
	overflow: hidden;
	line-height: 0;
	display: block
}

.case .list ul li .pic:after {
	content: '';
	position: absolute;
	top: 0;
	left: 0;
	right: 0;
	bottom: 0;
	z-index: 2;
	-webkit-transition: background .4s;
	transition: background .4s
}

.case .list ul li .pic .bg {
	display: block;
	width: 100%;
	-webkit-transition: opacity .4s;
	transition: opacity .4s
}

.case .list ul li .pic .logo {
	display: block;
	opacity: 0;
	filter: alpha(opacity=0);
	position: absolute;
	top: 50%;
	left: 50%;
	z-index: 3;
	margin-left: -100px;
	margin-top: -25px;
	width: 200px;
	height: 50px;
	line-height: 100%;
	-webkit-transition: opacity .4s;
	transition: opacity .4s
}

.case .list ul li .info {
	padding: 25px;
	background: #fff;
	-webkit-transition: height .4s;
	transition: height .4s;
	overflow: hidden
}

.case .list ul li .info h4 {
	font-size: 20px;
	color: #31475e;
	font-weight: 400;
	height: 30px;
	line-height: 30px;
	white-space: nowrap;
	text-overflow: ellipsis;
	overflow: hidden
}

.case .list ul li .info p {
	margin-top: 15px;
	font-size: 13px;
	font-weight: 400;
	color: #6a7c92;
	line-height: 24px;
	height: 120px;
	overflow: hidden
}