// original source:
// https://github.com/tobiasahlin/SpinKit
@duration: 3s;
@delayRange: 1s;

.create-wave-child(@numOfCol, @iter: 2) when (@iter <= @numOfCol) {
  div:nth-child(@{iter}) {
    animation-delay: -(@duration - (@delayRange / (@numOfCol - 1)) * (@iter - 1));
  }
  .create-wave-child(@numOfCol, (@iter + 1));
}

.sk-wave {
  height: 100px;
  margin: 100px auto;
  text-align: center;
  width: 50px;
  > div {
    animation: sk-stretchdelay @duration infinite ease-in-out;
    background-color: @brand-primary;
    display: inline-block;
    height: 100%;
    margin-right: 2px;
    width: 6px;
  }
  .create-wave-child(5)
}

@keyframes sk-stretchdelay {
  0%, 40%, 100% {
    transform: scaleY(0.4);
  }
  20% {
    transform: scaleY(1.0);
  }
}