body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  overflow: hidden;
  background: #fff;
  perspective: 500px;
}

.maru {
  width: 100px;
  height: 100px;
  background: linear-gradient(0deg, rgb(124, 0, 0), rgb(219, 62, 20), rgb(255, 144, 78));
  border-radius: 100%;
}


.kaiten {
  -webkit-transform-style: preserve-3d;
          transform-style: preserve-3d;
  -webkit-animation: rotationY 3000ms linear infinite;
          animation: rotationY 3000ms linear infinite;
}

@-webkit-keyframes rotationY {
  0% {
    -webkit-transform: rotateY(0deg);
            transform: rotateY(0deg);
  }
  100% {
    -webkit-transform: rotateY(360deg);
            transform: rotateY(360deg);
  }
}

@keyframes rotationY {
  0% {
    -webkit-transform: rotateY(0deg);
            transform: rotateY(0deg);
  }
  100% {
    -webkit-transform: rotateY(360deg);
            transform: rotateY(360deg);
  }
}