@grid_width: 60px;
@grid_num: 12;
@gutter: 10px;

@total_width: (@grid_width + @gutter * 2) * @grid_num;

.grid_width (@grid_num: 1) {
  width:  (@grid_width + @gutter * 2) * @grid_num - @gutter * 2;
}

.container {
	width: @total_width;
	margin-left: auto;
	margin-right: auto;
}
.grid(@grid_num) {
  	.grid_width (@grid_num);
	display: inline;
	margin-left: @gutter;
	margin-right: @gutter;
	float: left;
}

.prefix(@grid_num) {
	padding-left: (@grid_width + @gutter*2) * @grid_num;
}
.suffix(@grid_num) {
	padding-right: (@grid_width + @gutter*2) * @grid_num;
}

.push(@grid_num) {
	left: (@grid_width + @gutter*2) * @grid_num;
	position: relative;
}
.pull(@grid_num) {
	right: (@grid_width + @gutter*2) * @grid_num;
	position: relative;
}

.alpha {
	margin-left: 0;
}
.omega {
	margin-right: 0;
}