#background{width:100%;height:100%;z-index:-1;top:0;position:fixed}#loginbox{z-index:0}.big-btn{width:9rem;height:9rem;margin-bottom:24px}@media(max-width:330px){.big-btn{width:8rem;height:8rem;margin-bottom:12px;padding:6px 6px}.register-box-msg{padding:0 0 20px 0}img{width:100%}}