.at-container {
  height: 100%;
}
.at-item {
  width: 100px;
  height: 100px;

  animation-name: shake-center;
  animation-duration: 2.5s;
  animation-timing-function: linear;
  animation-delay: 0s;
  animation-iteration-count: infinite;
  animation-direction: normal;
  animation-fill-mode: none;

  /* shorthand
		animation: shake-center 1s linear 0s infinite normal none;*/
}
@keyframes shake-center {
  0% {
  }
  10% {
    transform: rotate(8deg);
  }
  20% {
    transform: rotate(-10deg);
  }
  30% {
    transform: rotate(10deg);
  }
  40% {
    transform: rotate(-10deg);
  }
  50% {
    transform: rotate(10deg);
  }
  60% {
    transform: rotate(-10deg);
  }
  70% {
    transform: rotate(10deg);
  }
  80% {
    transform: rotate(-8deg);
  }
  90% {
    transform: rotate(8deg);
  }
  100% {
    transform: rotate(0deg);
    transform-origin: 50% 50%;
  }
}