Shockwave hover animation

style.css

button {
  position: relative;
  outline: 1px solid transparent;
  border-radius: 50%;
  border: 1px solid #bdc3c7;
  width: 80px;
  height: 80px;
  background: none;
  user-select: none;
}
button:after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  display: block;
  border-radius: 50%;
  width: 79px;
  height: 79px;
}
button:hover {
  cursor: pointer;
  border: 1px solid #27ae60;
  transition: border-color 0.3s ease-in;
}
button:hover:after {
  animation: shockwave 1s ease-in infinite;
}

@keyframes shockwave {
  0% {
    transform: scale(1);
    box-shadow: 0 0 2px #27ae60;
    opacity: 1;
  }
  100% {
    transform: scale(1);
    opacity: 0;
    box-shadow: 0 0 50px #145b32, inset 0 0 10px #27ae60;
  }
}