@media screen and (max-width:640px){
    div.logo{left:0%;right:0%;}
    div.logo img{width:100%;}
    div.footer{bottom:2%;}
    div.footer .btn-group .btn{display: block;line-height:24px;height:24px;padding: 10px 14px;}
    div.footer .btn-group .btn + .btn{border-left:0;border-top: 1px solid rgba(256,256,256,0.7);}
    div.content{font-size: 24px;}
    #navBtn .stripe{width:40px;height:4px;margin-bottom:6px;}
    #navBtn{left:10px;top:14px;}
    body.nav #navBtn .stripe:nth-child(1){top:10px;}
    body.nav #navBtn .stripe:nth-child(3){bottom:10px;}
}