simple flex grid system

grid.scss

.row {
  display: flex;
  flex-wrap: nowrap;
  flex-shrink: 0;
  flex-grow: 0;
  align-items: flex-start;

  .col-auto {
    flex: 1;
  }

  @for $i from 1 through 12 {
    .col-#{$i} {
      width: percentage($i / 12);
    }

    .col-offset-#{$i} {
      margin-left: percentage($i / 12);
    }
  }
}