.rain{
  width:1px;
  height:8px;
  background:black;
  position:absolute;
  top:-8px;
  left:0px;
  
      -webkit-transition: all 3s ease-in 1s;
    -moz-transition: all 3s ease-in 1s;
    -o-transition: all 3s ease-in 1s;
    transition: all 3s ease-in 1s;
}