button {
  padding: 10px 20px;
  text-transform: uppercase;
  border-radius: 8px;
  font-size: 17px;
  font-weight: 500;
  color: #ffffff80;
  text-shadow: none;
  background: transparent;
  cursor: pointer;
  box-shadow: transparent;
  border: 1px solid #ffffff80;
  transition: 0.5s ease;
  user-select: none;
}

#btn:hover,
:focus {
  color: #ffffff;
  background: #0ef;
  border: 1px solid #0ef;
  text-shadow: 0 0 5px #ffffff, 0 0 10px #ffffff, 0 0 20px #ffffff;
  box-shadow: 0 0 5px #0ef, 0 0 20px #0ef, 0 0 50px #0ef, 0 0 100px #0ef;
  scale: 1.1;
}

#btn:active {
  transform: scale(0.8);
}