oocss_grids.css

.line, .lastUnit { overflow: hidden; _overflow: visible; _zoom: 1; }

.unit { float: left; _zoom: 1; }

.size1of1 { float: none; }

.size1of2 { width: 50%; }

.size1of3 { width: 33.333%; }

.size2of3 { width: 66.667%; }

.size1of4 { width: 25%; }

.size2of4 { width: 50%; }

.size3of4 { width: 75%; }

.size1of5 { width: 20%; }

.size2of5 { width: 40%; }

.size3of5 { width: 60%; }

.size4of5 { width: 80%; }

.lastUnit { float: none; _position: relative; _left: -3px; _margin-right: -3px; width: auto; }

oocss_grids.sass

=oocss-clearfix
  overflow: hidden
  _overflow: visible
  _zoom: 1

=unit
  float: left
  _zoom: 1

=size(!n, !m)
  @if !n == !m
    float: none
  @else
    width= percentage(!n / !m)

=lastUnit
  float: none
  _position: relative
  _left: -3px
  _margin-right: -3px
  width: auto

=grids
  .line, .lastUnit
    +oocss-clearfix
  .unit
    +unit
  .size1of1
    +size(1,1)
  @for !m from 1 through 5
    @for !n from 1 to !m
      .size#{!n}of#{!m}
        +size(!n, !m)
  .lastUnit
    +lastUnit