body {
  background-color: black;
  height: 100vh;
}
.bubble {
  color: black;
  border-radius: 50%;
  position: absolute;
  animation: zoom-in 4s linear 100ms normal forwards;
  transform: translate(-50%, -50%);
  display: flex;
  justify-content: center;
  height: 20px;
  width: 20px;
  padding: 5px;
  align-items: center;
}
@keyframes zoom-in {
  from {
    opacity: 100%;
    display: inline;
  }
  to {
    transform: scale(4);
    opacity: 0%;
  }
}