Generated by SassMeister.com.

SassMeister-input.scss

@mixin color-weight ($class, $base-color, $weight: 4) {
  $bg-color: null;
  
  @for $i from 1 through 8 {
    @if $i < 4 {
      $weight: $weight - 1;
      $bg-color: lighten($base-color, $weight * 10%);
    } @else if $i == 4 {
      $weight: 0;
      $bg-color: $base-color;
    } @else {
      $weight: $weight + 1;
      $bg-color: darken($base-color, $weight * 10%);
    }
    
    .#{$class}-#{$i} { background-color: $bg-color; }
  }
}

@include color-weight(bg-blue, #1483ff);
@include color-weight(mad, red);

SassMeister-output.css

.bg-blue-1 {
  background-color: #add4ff;
}

.bg-blue-2 {
  background-color: #7ab9ff;
}

.bg-blue-3 {
  background-color: #479eff;
}

.bg-blue-4 {
  background-color: #1483ff;
}

.bg-blue-5 {
  background-color: #006ae0;
}

.bg-blue-6 {
  background-color: #0052ad;
}

.bg-blue-7 {
  background-color: #003a7a;
}

.bg-blue-8 {
  background-color: #002247;
}

.mad-1 {
  background-color: #ff9999;
}

.mad-2 {
  background-color: #ff6666;
}

.mad-3 {
  background-color: #ff3333;
}

.mad-4 {
  background-color: red;
}

.mad-5 {
  background-color: #cc0000;
}

.mad-6 {
  background-color: #990000;
}

.mad-7 {
  background-color: #660000;
}

.mad-8 {
  background-color: #330000;
}