app/node_modules/ng-zorro-antd/divider/style/patch.less

.@{divider-prefix-cls} {
  &-dotted {
    background: none;
    border-color: @divider-color;
    border-style: dotted;
    border-width: @border-width-base 0 0;
  }

  &-horizontal&-with-text&-dotted {
    &::after,
    &::before {
      border-style: dotted none none;
    }
  }

  &-vertical&-dotted {
    border-width: 0 0 0 @border-width-base;
  }
}