@keyframes shake {
  0% { transform: translateX(0); }
  25% { transform: translateX(-10px); }
  50% { transform: translateX(10px); }
  75% { transform: translateX(-10px); }
  100% { transform: translateX(0); }
}
#result.shake {
  animation: shake 0.5s ease-in-out;
}
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}
#result {
  animation: fadeIn 1s ease-in-out;
}