@include b(col) {
  position: relative;
  float: left;
  box-sizing: border-box;
  background-clip: content-box;

  @for $i from 1 through 24 {
    &-#{$i} {
      width: calc($i * 100% / 24);
    }
  }

  @for $i from 1 to 24 {
    &-offset-#{$i} {
      margin-left: calc($i * 100% / 24);
    }
  }
}