Calculates a value based on the $column-spacing.

function-horizontal-rhythm

@function horizontal-rhythm($fraction: 1/2)
{
	$value: return-unitless( $fraction * $column-spacing );

	@if $column-spacing-unit == 1rem {
		@return $value/10*1rem;
	}
	@if $column-spacing-unit == 1em {
		@return $value/$base-font-size*1em;
	}
	@if $column-spacing-unit == 1px {
		@return $value*1px;
	}
	@if $column-spacing-unit == 1% {
		@return $value/$base-font-size*1em;
	}
}