@keyframes sisAnimasyon {
  0% {
    box-shadow: 0 0 0 0 rgba(255, 255, 255, 0.4);
  }
  70% {
    box-shadow: 0 0 0 30px rgba(255, 255, 255, 0.4);
  }
  100% {
    opacity: 0;
  }
}

.sis {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background-color: transparent;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation: sisAnimasyon 2s infinite;
}