Elastic Press Button

<button class="elastic-btn">Add to Cart</button>

.elastic-btn {
  padding: 12px 30px;
  background: #1a1a1a;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: transform .1s;
}
.elastic-btn:active {
  animation: elastic .5s cubic-bezier(.34,1.56,.64,1);
}
@keyframes elastic {
  0% { transform: scale(1); }
  30% { transform: scale(.92, 1.08); }
  50% { transform: scale(1.05, .95); }
  70% { transform: scale(.98, 1.02); }
  100% { transform: scale(1); }
}