css 设置body背景图片铺满

     background-image: url(../../../assets/images/workflow/work.png); 
     background-repeat: no-repeat;
     background-position: center;
     background-attachment: fixed;
     background-size: cover;
     -webkit-background-size: cover;
     -moz-background-size: cover;
     -o-background-size: cover;