.box {
width: 100%;
display: -webkit-box;
display: -moz-box;
}

.box > * {
-webkit-box-flex: 1;
-moz-box-flex: 1;
}
 
.nav4 ul{
	position:fixed;
	z-index:1000;
	bottom:0;
	width:100%;
	background:#333;
}
.nav4 li{
	border-left:1px solid #666;
	height:40px;
	line-height:40px;
	border-bottom:0;
	border-right:0;
	position:relative;
}
.nav4 li:nth-of-type(1){border-left;0;}
.nav4 li a{
	font-size:1rem;
	border-bottom:0;
	display:block;
	line-height:40px;
	text-align: center;
}
.nav4 li a:only-child span{
	background:none;
	padding-left:0;
}
 
.nav4 li a.on + dl{
	display: block;
}
.nav4 li a span{
	color: #fff;
	font-size:1.1rem; 
}

.nav4 dl{
	display:none;
	position:absolute;
	z-index:220;
	bottom:40px;
	width:302%;
	background-color:Rgba(0,0,0,0.7);
	transition:all .5s;
}

.nav4 dl dd{
    padding:0;
    margin:0;
	height:40px;
	line-height:40px;
	text-align:center;
	border-bottom:1px solid Rgba(100,100,100,0.5)
}
.nav4 dl dd:last-of-type{
	background:none;
}
.nav4 dl dd a{
	display:block;
	color:#000;
	white-space: pre;
	overflow: hidden;
	text-overflow: ellipsis;
	background:none;font-size:1rem;
}
.nav4 dl dd a span{	font-size:1rem;color:#fff;}

.nav4 .masklayer_div{
	display: none;
	position: fixed;
	top: 0;
	left: 0;
	width: 100%;
	height: 100%;
	z-index: 180;
	background: rgba(0,0,0,0);
}
.nav4 .masklayer_div.on{display: block;}