.container {
  margin: 1.739rem auto;
  width: 0.7rem;
  height: 0.7rem;
  position: relative;
}
.container > div {
  width: 30%;
  height: 100%;
  position: absolute;
  left: 35%;
  top: 0;
}
.container > div:before {
  content: '';
  display: block;
  margin: 0 auto;
  width: 25%;
  height: 25%;
  background-color: #333;
  border-radius: 100%;
  -webkit-animation: fade-cricle 1.2s infinite ease-in-out both;
          animation: fade-cricle 1.2s infinite ease-in-out both;
}
.container > div:nth-child(2) {
  -webkit-transform: rotate(30deg);
      -ms-transform: rotate(30deg);
          transform: rotate(30deg);
}
.container > div:nth-child(2):before {
  -webkit-animation-delay: -1.1s;
          animation-delay: -1.1s;
}
.container > div:nth-child(3) {
  -webkit-transform: rotate(60deg);
      -ms-transform: rotate(60deg);
          transform: rotate(60deg);
}
.container > div:nth-child(3):before {
  -webkit-animation-delay: -1s;
          animation-delay: -1s;
}
.container > div:nth-child(4) {
  -webkit-transform: rotate(90deg);
      -ms-transform: rotate(90deg);
          transform: rotate(90deg);
}
.container > div:nth-child(4):before {
  -webkit-animation-delay: -0.9s;
          animation-delay: -0.9s;
}
.container > div:nth-child(5) {
  -webkit-transform: rotate(120deg);
      -ms-transform: rotate(120deg);
          transform: rotate(120deg);
}
.container > div:nth-child(5):before {
  -webkit-animation-delay: -0.8s;
          animation-delay: -0.8s;
}
.container > div:nth-child(6) {
  -webkit-transform: rotate(150deg);
      -ms-transform: rotate(150deg);
          transform: rotate(150deg);
}
.container > div:nth-child(6):before {
  -webkit-animation-delay: -0.7s;
          animation-delay: -0.7s;
}
.container > div:nth-child(7) {
  -webkit-transform: rotate(180deg);
      -ms-transform: rotate(180deg);
          transform: rotate(180deg);
}
.container > div:nth-child(7):before {
  -webkit-animation-delay: -0.6s;
          animation-delay: -0.6s;
}
.container > div:nth-child(8) {
  -webkit-transform: rotate(210deg);
      -ms-transform: rotate(210deg);
          transform: rotate(210deg);
}
.container > div:nth-child(8):before {
  -webkit-animation-delay: -0.5s;
          animation-delay: -0.5s;
}
.container > div:nth-child(9) {
  -webkit-transform: rotate(240deg);
      -ms-transform: rotate(240deg);
          transform: rotate(240deg);
}
.container > div:nth-child(9):before {
  -webkit-animation-delay: -0.4s;
          animation-delay: -0.4s;
}
.container > div:nth-child(10) {
  -webkit-transform: rotate(270deg);
      -ms-transform: rotate(270deg);
          transform: rotate(270deg);
}
.container > div:nth-child(10):before {
  -webkit-animation-delay: -0.3s;
          animation-delay: -0.3s;
}
.container > div:nth-child(11) {
  -webkit-transform: rotate(300deg);
      -ms-transform: rotate(300deg);
          transform: rotate(300deg);
}
.container > div:nth-child(11):before {
  -webkit-animation-delay: -0.2s;
          animation-delay: -0.2s;
}
.container > div:nth-child(12) {
  -webkit-transform: rotate(330deg);
      -ms-transform: rotate(330deg);
          transform: rotate(330deg);
}
.container > div:nth-child(12):before {
  -webkit-animation-delay: -0.1s;
          animation-delay: -0.1s;
}
@-webkit-keyframes fade-cricle {
  0%,
  39%,
  100% {
    opacity: 0;
  }
  40% {
    opacity: 1;
  }
}
@keyframes fade-cricle {
  0%,
  39%,
  100% {
    opacity: 0;
  }
  40% {
    opacity: 1;
  }
}