#col {
  width: 50%;
  margin: 0 auto;
}

.loader {
  content: ' ';
  border: 5px solid #333;
  border-radius: 30px;
  height: 30px;
  left: 50%;
  margin: -15px 0 0 -15px;
  opacity: 0;
  position: absolute;
  top: 50%;
  width: 30px;
  animation: pulsate 1s ease-out;
  animation-iteration-count: infinite;
}

@keyframes pulsate {
  0% {
    transform: scale(.1);
    opacity: 0.0;
  }

  50% {
    opacity: 1;
  }

  100% {
    transform: scale(1.2);
    opacity: 0;
  }
}