css毛玻璃效果

#left:before{

   position: relative;

    z-index: -1;

    filter: blur(20px);

    background-color: #FFFFFF;

} 

  #left{

  /*border: 1px solid red;*/

  position: relative;

  z-index: 1;

  margin-top: 250px;

  margin-left:210px;

   200px;

  height: 300px;

  background-color: white;

  box-shadow: 0px 0px 20px black;

  overflow: hidden;

  float: left;

  }

 

 

 

  #activity{

  position: relative;

  z-index: 1;

  margin-top: 50px;

  height: 450px;

   100%;

 background-image: url(../img/bg.JPG);

     

background-attachment: fixed;

  background-repeat: no-repeat;

  background-size: cover;

   box-shadow: 0px 0px 20px black;

  overflow: hidden;

 

  overflow: hidden;

  float: left;

 

  }

#activity:before{

position: relative;

z-index: -1;

filter: blur(20px);

  background-image: url(../img/bg.JPG);

}