登录页面背景图片设置

       min-height:100vh;
        width: 100%;
        background: url('/Public/img/admin/bg.png') no-repeat center 0px;
        background-size:cover;
        background-position: center 0; 
        background-repeat: no-repeat;  
        background-attachment: fixed; 
        -webkit-background-size: cover;  
        -o-background-size: cover;  
        -moz-background-size: cover;  
        -ms-background-size: cover;