papercss/src/utilities/_borders.scss

.border {
  @include color('border-color','primary' );
  border-style: solid;
  border-width: 2px;
}

.border,
.border-1,
.child-borders>*:nth-child(6n+1) {
  @include border-style(1);
}

.border-2,
.child-borders>*:nth-child(6n+2) {
  @include border-style(2);
}

.border-3,
.child-borders>*:nth-child(6n+3) {
  @include border-style(3);
}

.border-4,
.child-borders>*:nth-child(6n+4) {
  @include border-style(4);
}

.border-5,
.child-borders>*:nth-child(6n+5) {
  @include border-style(5);
}

.border-6,
.child-borders>*:nth-child(6n+6) {
  @include border-style(6);
}

.child-borders>* {
  @include color('border-color', 'primary');
  border-style: solid;
  border-width: 2px;
}

.border-white {
  @include color('border-color', 'white');
}

.border-dotted {
  border-style: dotted;
}

.border-dashed {
  border-style: dashed;
}

.border-thick {
  border-width: 5px;
}

@each $colorName, $color in $colors {
  .border-#{$colorName} {
    @include color('border-color', #{$colorName});
  }
}