.pre-loader {
  display: flex;
  width: 100%;
  min-height: 100vh;
  justify-content: center;
  align-items: center;
  .loader-item {
    width: 10px;
    height: 10px;
    background: black;
  }
  .pre-loader-center {
    align-items: center;
    display: flex;
    flex-direction: column;
  }
  .pre-loader-wrapper {
    width: 50px;
    height: 50px;
    display: flex;
    flex-wrap: wrap;
  }
  @for $i from 0 through 16 {
    .loader-item:nth-child(#{$i}) {
      @if $i % 2 == 0 {
        animation-delay: #{$i * 50 * random(5)}ms;
        animation-direction: reverse;
      } @else {
        animation-delay: #{$i * -50 * random(5)}ms;
        animation-direction: alternate;
      }
    }
  }
  .loader-item {
    animation: flickering 0.4s linear alternate infinite;
  }
  @keyframes flickering {
    0% {
      opacity: 1;
    }
    25% {
      opacity: 1;
    }
    26% {
      opacity: 0;
    }
    100% {
      opacity: 0;
    }
  }
}
html.dark {
  .pre-loader {
    .loader-item {
      background: white;
    }
  }
}