.regular-price {
    display: inline-block;
    color: #999;
    text-decoration: line-through;
    animation: pulse 2s infinite;
  }+

  @keyframes pulse {
    0% { transform: scale(1); opacity: 0.8; }
    50% { transform: scale(1.15); opacity: 1; }
    100% { transform: scale(1); opacity: 0.8; }
  }