-$spacing: (('none', 0), ('xxs', $-xxs), ('xs', $-xs), ('s', $-s), ('m', $-m), ('l', $-l), ('xl', $-xl), ('xxl', $-xxl));
+$spacing: (('none', 0), ('xxs', $-xxs), ('xs', $-xs), ('s', $-s), ('m', $-m), ('l', $-l), ('xl', $-xl), ('xxl', $-xxl), ('auto', auto));