super basic Sass grid

basic-grid.scss

$total-cols: 12;

.col-group {
  position: relative;
  // @include clearfix; // bourbon
  // @include pie-clearfix; // compass
}

.col {
  float: left;
  padding: 0 10px;
}

@for $span from 1 through $total-cols {
  .col-span-#{$span} {
    width: floor(10000 / ($total-cols / $span)) * .01%; // allows for 2 decimal places
  }
}