@keyframes shake-cart {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-4px); }
  40% { transform: translateX(4px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}

.shake-cart {
  animation: shake-cart 2s infinite;
}