.loader {
  width: 50px;
  height: 20px;
  display: flex;
  justify-content: space-around;
  position: relative;
  padding: 5px;
  border-radius: 5px;
  box-sizing: content-box;
  margin: auto;
}

.loader-bars:before, .loader-bars:after, .loader-bars span {
  content: '';
  display: block;
  width: 8px;
  background-color: #FFF;
  animation: grow 1.5s linear infinite;
}

.loader-bars.loader.mini {
  width: auto;

  &:before, &:after, & span { width: 4px; }
}

.loader-bars:before { left: 0; }
.loader-bars:after { animation-delay: 0.5s; }
.loader-bars span { animation-delay: 1s; }

@keyframes grow {
  0% {
    transform: scaleY(0);
    opacity: 0;
  }

  50% {
    transform: scaleY(1);
    opacity: 1.6;
  }

  100% {
    transform: scaleY(0);
    opacity: 0;
  }
}