2D圆周环绕动画 #

.outer {
  display: flex;
  justify-content: center;
  width: 100px;
  height: 100px;
  background-color: #6a5acd8c;
  position: relative;
}
/**竖向辅助线**/
.vertical-line {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  height: 100%;
  width: 1px;
  background: #000;
}
/**横向辅助线**/
.horizontal-line {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 100%;
  height: 1px;
  background: #000;
}
.inner {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background-color: #6a5acdeb;
  transform-origin: 50% 50px; /**50px为环绕半径*/
  animation: an-circle 3s ease-in-out infinite;
}
@keyframes an-circle {
  to {
    transform: rotate(1turn);
  }
}