#myBtn {
  display: none;
  position: fixed;
  bottom: 20px;
  right: 30px;
  z-index: 99;
  border: none;
  outline: none;
  background-color: rgba(100,176,63,0.5);
  color: white;
  cursor: pointer;
  /*padding: 15px;*/
  border-radius: 6px;
  font-size: 18px;
}

#myBtn:hover {
  background-color: #64b03f;
}