.btn {
  overflow: hidden;
  position: relative;
  z-index: 1;
}

.btn>.wave-ripple {
  border-radius: 50%;
  background-color: rgba(255, 255, 255, 0.33);
  transform: scale(0);
  animation: wave-ripple 0.6s linear;
}

a {
  overflow: hidden;
  position: relative;
  z-index: 1;
}

a>.wave-ripple {
  border-radius: 50%;
  background-color: rgba(255, 255, 255, 0.33);
  transform: scale(0);
  animation: wave-ripple 0.6s linear;
}

@keyframes wave-ripple {
  to {
    transform: scale(3);
    opacity: 0;
  }
}