html, body {
  color: white;
  background-color: black;
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
}

div {
  width: 1px;
  height: 1px;
  background-color: grey;
  left: 50%;
  top: 50%;    
  border-radius: 50%;
  position: absolute;
  transition-property: all;
  transition-duration: 5s;
  transition-timing-function: ease-in;
}