spacing.scss in sass-zero-0.0.28

- old
+ new

@@ -25,6 +25,6 @@
 
 $size-auto:   auto;
 $size-full:   100%;
 $size-screen: 100vw;
 
-$size-map: ("xs": $size-1, "sm": $size-2, "md": $size-4, "lg": $size-6, "xl": $size-8, "2xl": $size-10);
+$size-map: ("xs": $size-1, "sm": $size-2, "md": $size-4, "lg": $size-6, "xl": $size-8, "2xl": $size-10, "3xl": $size-12);