.loader {
  width: 22em;
  height: 11em;
  position: relative;
  overflow: hidden;
  margin: auto;
}

.loader::before,
.loader::after {
  content: "";
  position: absolute;
  bottom: 0;
}

.loader::before {
  width: inherit;
  height: 0.2em;
  background-color: white;
}

.loader::after {
  box-sizing: border-box;
  width: 50%;
  height: inherit;
  border: 0.2em solid white;
  border-radius: 50%;
  left: 25%;
}

.loader span {
  position: absolute;
  width: 5%;
  height: 10%;
  background-color: white;
  border-radius: 50%;
  bottom: 0.2em;
  left: -5%;
  animation: 2s linear infinite;
  transform-origin: 50% -4em;
  animation-name: run, rotating;
}

.loader span:nth-child(2) {
  animation-delay: 0.075s;
}
.loader span:nth-child(3) {
  animation-delay: 0.15s;
}

@keyframes run {
  0% {
    left: -5%;
  }
  10%,
  60% {
    left: calc((100% - 5%) / 2);
  }
  70%,
  100% {
    left: 100%;
  }
}

@keyframes rotating {
  0%,
  10% {
    transform: rotate(0deg);
  }
  60%,
  100% {
    transform: rotate(-1turn);
  }
}