.whatsapp-button {
      position: fixed;
      bottom: 20px;
      left: 20px;
      z-index: 99;
      background-color: #25d366;
      border-radius: 30px;
      color: #ffffff;
      text-decoration: none;
      width: 20px;
      height: 20px;
      font-size: 30px;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      -webkit-box-shadow: 0px 0px 25px -6px rgba(0, 0, 0, 1);
      -moz-box-shadow: 0px 0px 25px -6px rgba(0, 0, 0, 1);
      box-shadow: 0px 0px 25px -6px rgba(0, 0, 0, 1);
      animation: effect 5s infinite ease-in;
  }

  @keyframes effect {

      20%,
      100% {
          width: 50px;
          height: 50px;
          font-size: 30px;
      }

      0%,
      10% {
          width: 55px;
          height: 55px;
          font-size: 35px;
      }

      5% {
          width: 50px;
          height: 50px;
          font-size: 30px;
      }
  }