grav-theme-libretic/scss/nucleus/functions/_range.scss

@function lower-bound($range){
	@if length($range) <= 0 {
		@return 0;
	}
	@return nth($range,1);
}

@function upper-bound($range) {
	@if length($range) < 2 {
		@return 999999999999;
	}
	@return nth($range, 2);
}