.heart {
    color: red;
    font-size: 50px;
    animation: heart-pulse 1.0s infinite ease-out;
  }
  
  @keyframes heart-pulse {
    0% {
      transform: scale(0); /* scaling to 0 */
    }
    50% {
      transform: scale(1.0); /* increasing the size */
    }
    70% {
      transform: scale(0.65); /* decreasing the size */
    }
    100% {
      transform: scale(0); /* seeting back to initial size */
    }
  }