KNACSS/sass/_grids.scss

/* ----------------------------- */
/* ==grids                       */
/* ----------------------------- */

/**
 * Equal grids with 2% gutter 
 * 1. Direct childrens are floating
 * 2. Gutter
 */
[class*=grid] > * {
	float: left; /* 1 */

	+ * {
		margin-left: 2%; /* 2 */
	}
}

.grid2 > * { width: 49%; }
.grid3 > * { width: 32%; }
.grid4 > * { width: 23.5%; }
.grid5 > * { width: 18.4%; }
.grid6 > * { width: 15%; }

/**
 * Unequal grids (1-2, 2-1, 1-3 and 3-1) 
 */
.grid2-1 > *:first-child,
.grid1-2 > * + * { width: 66%; }
.grid1-2 > *:first-child,
.grid2-1 > * + * { width: 32%; }
.grid1-3 > *:first-child,
.grid3-1 > * + * { width: 23.5%; }
.grid3-1 > *:first-child,
.grid1-3 > * + * { width: 74.5%; }

/**
 * Responsive grids
 */
@include mq(small) {
	.grid4 > * { width: 49% !important; } 
	.grid4 > :first-child + * + * { margin-left: 0 !important; }
	.grid6 > * { width: 32% !important; }  
	.grid6 > :first-child + * + * + * { margin-left: 0 !important; }
}