#myBtn {
  display: none;
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 99;
  font-size: 24px;
  border: none;
  outline: 1px solid grey;
  background-color: white;
  color: grey;
  cursor: pointer;
  padding-bottom: 4px;
  padding-top: 4px;
  padding-left: 15px;
  padding-right: 15px;
  border-radius: 10px;
  width: 56px;
}

#myBtn:hover {
  background-color: grey;
  color: white;
}