.f_nav{  margin:10px auto;padding-top:18px;}
.f_nav li{ width:6rem;  text-align:center; }
.f_bg{   background:#CCCCCC; padding:19px 0; clear:both;}
.one{

width: 80%;

height: 100px;

float: left;

box-sizing: border-box;

}

.box-top {
	height:40px;
	position:fixed;
	width:100%;
	left:0;
	top:0;
	background-color:rgba(255,255,255,0);
	z-index:1;
	transition:all 0.5s ease-in-out	0s;
}
.box-top.active {
	background-color:rgba(255,255,255,1);
	height:80px;
}
 .fixed {
	height:30px;
	width:70%;
	border-radius:15px;
	border:none;
	background-color:#eee;
	position:fixed;
	left:20%;
	top:5px;
	box-shadow:none;
	bottom:auto;
}