style.css

* {
  -webkit-box-sizing: border-box;
          box-sizing: border-box;
}

body {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
      -ms-flex-pack: center;
          justify-content: center;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
  background: #fafafa;
  height: 100vh;
  margin: 0;
  padding: 0;
}

.wrapper {
  height: 200px;
  width: 200px;
  border-radius: 50%;
  -webkit-box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
          box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
}

.circle {
  -webkit-box-sizing: border-box;
          box-sizing: border-box;
  height: 200px;
  width: 200px;
  border-radius: 50%;
  padding-left: 50px;
  background-image: -webkit-gradient(linear, right top, left top, from(#fff), color-stop(50%, #fff), color-stop(50%, #000), to(#000));
  background-image: linear-gradient(to left, #fff, #fff 50%, #000 50%, #000);
  -webkit-animation: roll 20s linear infinite;
          animation: roll 20s linear infinite;
}

.yinyang {
  position: relative;
  background: #fff;
  height: 100px;
  width: 100px;
  border-radius: 50%;
  background-image: -webkit-gradient(linear, right top, left top, from(#fff), color-stop(50%, #fff), color-stop(50%, #000), to(#000));
  background-image: linear-gradient(to left, #fff, #fff 50%, #000 50%, #000);
  -webkit-animation: roll 4s linear infinite;
          animation: roll 4s linear infinite;
  animation-direction: reverse;
}

.yinyang::before {
  content: "";
  position: absolute;
  top: 0;
  left: 50%;
  -webkit-transform: translate(-50%);
          transform: translate(-50%);
  background: #fff;
  border: 18px solid #000;
  border-radius: 50%;
  width: 14px;
  height: 14px;
}

.yinyang::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%);
          transform: translate(-50%);
  background: #000;
  border: 18px solid #fff;
  border-radius: 50%;
  width: 14px;
  height: 14px;
}

@-webkit-keyframes roll {
  from {
    -webkit-transform: rotate(0deg);
            transform: rotate(0deg);
  }
  to {
    -webkit-transform: rotate(-360deg);
            transform: rotate(-360deg);
  }
}

@keyframes roll {
  from {
    -webkit-transform: rotate(0deg);
            transform: rotate(0deg);
  }
  to {
    -webkit-transform: rotate(-360deg);
            transform: rotate(-360deg);
  }
}