body { 
     background-color: #efefef;
     background-image: url(https://images.cnblogs.com/cnblogs_com/yaoguanquan/1811741/o_200722090843111.png);
     background-repeat: no-repeat; 
     background-attachment: fixed; 
     background-position: center 0; 
     background-size: cover; 
  }
#home{
     background:transparent;<!--背景透明-->
　  color:#fff;<!--字体颜色-->
　  background-color:rgba(255,255,255,0.15)<!--最后一个参数设置透明度，前面三个是RGB颜色值-->
}