<div class="circle">
  <div class="dott"></div>
</div>

body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}
.circle {
  width: 150px;
  height: 150px;
  border: 2px solid black;
  border-radius:50%;
  animation: rotate 2s infinite linear;
}
.dott {
  width: 40px;
  height: 40px;
  background: green;
}
@keyframes rotate {
  from {
    
  }
  to {
    transform: rotate(360deg);
  }
}