style.css

.main {

  display: flex;
  justify-content: center;
  align-items: center;
  width: 100vw;
  height: 100vh;
  background-color: rgba(202, 240, 248, 1);
}

.box {

  width: 250px;
  height: 250px;
  background: rgba(3, 4, 94, 1);
  display: flex;
  justify-content: center;
  align-items: center;
  box-shadow: 4px 4px 20px rgba(0, 0, 0, 0.3);
}

.container {

  height: 15px;
  width: 105px;
  display: flex;
  position: relative;
  /* flex-wrap: wrap; */
}

.circle {

  width: 15px;
  height: 15px;
  border-radius: 50%;
  background-color: white;
  animation: circulate 500ms linear 0ms infinite;
  margin-right: 30px;
}

.circle:first-child {

  position: absolute;
  top: 0;
  left: 0;
  animation: pop-out 500ms linear 0ms infinite;
}

.circle:last-child {

  position: absolute;
  top: 0;
  right: 0;
  margin-right: 0;
  animation: pop-out 500ms linear 0s infinite reverse;
}

@keyframes pop-out {

  from {

    transform: scale(0, 0);
    opacity: 0;
  } to {

    transform: scale(1, 1);
    opacity: 1;
  }
}

@keyframes circulate {

  from {

    transform: translateX(0px);
  } to {
      
    transform: translateX(45px);
  }
}