.banner{position: relative;}
.banner-pic{max-width:1920px;margin:0 auto;width:100%;position: relative;z-index:1;}
.banner-pic img{width:100%;height:auto;}
.banner a.logo{display:block;width:10.5%;height:11.6%;background:transparent;position: absolute;left:23%;top:7%;z-index:2;}
.main-box{max-width:1920px;margin:0 auto;}
.main-box .img-box img{max-width:100%;height:auto;}
.link-bt{position: fixed;right:5%;top:47.2%;z-index:99;width:96.5px;transition: all 1s;}
.link-bt a{display: block;}
.link-bt a img{width:100%;height:auto;}

@media only screen and (max-height: 850px) {
	.link-bt{width:80px;}
}

@media only screen and (max-height: 750px) {
	.link-bt{width:70px;}
}

@media only screen and (max-height: 700px) {
	.link-bt{width:60px;}
}