<div id="loading">
  <span></span>
  <span></span>
  <span></span>
  <span></span>
  <span></span>
</div>

#loading {
  height: 40px;
  position: absolute;
  left: calc(50% - 40px);
  top: calc(50% - 10px);
  text-align: center;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

#loading span {
  width: 10px;
  height: 10px;
  margin: 2px;
  background: #868686;
  border-radius: 10px;
  display: inline-block;
  transition: all 400ms ease;
  animation: wave 2.5s ease infinite;
}

#loading span:nth-child(2) {
  animation-delay: 100ms;
}

#loading span:nth-child(3) {
  animation-delay: 200ms;
}

#loading span:nth-child(4) {
  animation-delay: 300ms;
}

#loading span:nth-child(5) {
  animation-delay: 400ms;
}

@keyframes wave {
  0%, 100% {
    transform: translate(0, 0);
    background: #00b200;
  }
  40% {
    transform: translate(0, 20px);
    opacity: 0;
  }
  10% {
    transform: translate(0, -20px);
    background: #00ff00;
  }
}