.gm-grid-float-columns(@class) {
  .col(@index) {
    // initial
    @item: ~'.gm-grid-col@{class}-@{index}';
    .col((@index + 1), @item);
  }
  .col(@index, @list) when (@index =< @gm-grid-columns) {
    // general
    @item: ~'.gm-grid-col@{class}-@{index}';
    .col((@index + 1), ~'@{list}, @{item}');
  }
  .col(@index, @list) when (@index > @gm-grid-columns) {
    // terminal
    @{list} {
      flex: 0 0 auto;
      float: left;
    }
  }
  .col(1); // kickstart it
}

.gm-grid-loop-columns(@index, @class) when (@index > 0) {
  .gm-grid-col@{class}-span-@{index} {
    display: block;
    box-sizing: border-box;
    width: percentage((@index / @gm-grid-columns));
  }

  .gm-grid-col@{class}-offset-@{index} {
    margin-left: percentage((@index / @gm-grid-columns));
  }
  .gm-grid-loop-columns((@index - 1), @class);
}

.gm-grid-loop-columns(@index, @class) when (@index = 0) {
  .gm-grid-col@{class}-span-@{index} {
    display: none;
  }

  .gm-grid-col@{class}-offset-@{index} {
    margin-left: 0;
  }
}

.gm-grid(@class: ~'') {
  .gm-grid-float-columns(@class);
  .gm-grid-loop-columns(@gm-grid-columns, @class);
}