<!doctype html>
<html style="height:100%;overflow:hidden">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
<style>
@media screen and (max-width:750px){
body{background: url(bg.jpg) no-repeat left top!important;background-size:auto 100%;}
.main{
margin-left:0!important;
width:100%!important;
padding-top:30vw!important;
}
.main img{width:100%;}
}
</style>
<title></title>
</head>
<body style="text-align: center;background: url(bg.jpg) no-repeat center top;background-size:100% 100%;height:100%;margin:0;">
<div class="main" style="width:1100px;padding-top:300px;margin-left:40%;">
<img src="a.gif" alt="">
</div>
</body>
</html>