#ball
{
  height: 350px;
  width:350px;
  background:radial-gradient(circle at 100px 100px, #3f3f3f, #000);;
  border-radius:50%;
  display:flex;
  align-items:center;
  justify-content:center;
}
#output
{
  width: 40%;
  height: 40%;
  border-radius:50%;
  background-color:white;
  overflow:hide;
  display:flex;
  justify-content:center;
  align-items:center;
}