Transparent scrollbar

Question

How to make scrollbar transparent? Only css. Only for webkit browsers. My code here.

   div{
  width:410px;
  height:100px;
  overflow-y:overlay;
  border:1px solid green;
  position:relative;
}

::-webkit-scrollbar{
  width:20px;
} 

::-webkit-scrollbar-thumb{
  background-color:rgba(0,0,0,1);
}  

Answer 1

div
{
  width:410px;
  height:100px;
  overflow-y:overlay;
  border:1px solid green;
  position:relative;
}

::-webkit-scrollbar{
  width:20px;
} 

::-webkit-scrollbar-thumb{
   background-color: rgba(255,255,255,1);

}