.pre-loader {
  display: flex;
  width: 100%;
  min-height: 100vh;
  justify-content: center;
  align-items: center;
}
.pre-loader .loader-item:nth-child(0) {
  animation-delay: 0ms;
  animation-direction: reverse;
}
.pre-loader .loader-item:first-child {
  animation-delay: -0.2s;
  animation-direction: alternate;
}
.pre-loader .loader-item:nth-child(2) {
  animation-delay: 0.1s;
  animation-direction: reverse;
}
.pre-loader .loader-item:nth-child(3) {
  animation-delay: -0.15s;
  animation-direction: alternate;
}
.pre-loader .loader-item:nth-child(4) {
  animation-delay: 1s;
  animation-direction: reverse;
}
.pre-loader .loader-item:nth-child(5) {
  animation-delay: -0.25s;
  animation-direction: alternate;
}
.pre-loader .loader-item:nth-child(6) {
  animation-delay: 0.3s;
  animation-direction: reverse;
}
.pre-loader .loader-item:nth-child(7) {
  animation-delay: -1.05s;
  animation-direction: alternate;
}
.pre-loader .loader-item:nth-child(8) {
  animation-delay: 0.8s;
  animation-direction: reverse;
}
.pre-loader .loader-item:nth-child(9) {
  animation-delay: -0.9s;
  animation-direction: alternate;
}
.pre-loader .loader-item:nth-child(10) {
  animation-delay: 0.5s;
  animation-direction: reverse;
}
.pre-loader .loader-item:nth-child(11) {
  animation-delay: -2.75s;
  animation-direction: alternate;
}
.pre-loader .loader-item:nth-child(12) {
  animation-delay: 2.4s;
  animation-direction: reverse;
}
.pre-loader .loader-item:nth-child(13) {
  animation-delay: -0.65s;
  animation-direction: alternate;
}
.pre-loader .loader-item:nth-child(14) {
  animation-delay: 0.7s;
  animation-direction: reverse;
}
.pre-loader .loader-item:nth-child(15) {
  animation-delay: -3s;
  animation-direction: alternate;
}
.pre-loader .loader-item:nth-child(16) {
  animation-delay: 2.4s;
  animation-direction: reverse;
}
.pre-loader .pre-loader-center {
  align-items: center;
  display: flex;
  flex-direction: column;
}
.pre-loader .pre-loader-wrapper {
  width: 50px;
  height: 50px;
  display: flex;
  flex-wrap: wrap;
}
.pre-loader .loader-item {
  width: 10px;
  height: 10px;
  background: #000;
  animation: flickering 0.4s steps(2, jump-none) infinite alternate;
}
@keyframes flickering {
  0% {
    opacity: 1;
  }
  25% {
    opacity: 1;
  }
  26% {
    opacity: 0;
  }
  to {
    opacity: 0;
  }
}