Inherit undefined media grid properties from global neat-grid

#532

core/_neat.scss

@@ -11,6 +11,7 @@
 @import "neat/functions/neat-column-width";
 @import "neat/functions/neat-column-ratio";
 @import "neat/functions/neat-float-direction";
+@import "neat/functions/neat-merge-defaults";
 @import "neat/functions/neat-opposite-direction";
 @import "neat/functions/neat-parse-columns";
 @import "neat/functions/neat-parse-media";

core/neat/functions/_neat-merge-defaults.scss

@@ -0,0 +1,23 @@
+@charset "UTF-8";
+/// Apply Neat's default properties to undefined values within a map.
+///
+/// @argument {map} $grid
+///
+/// @return {map}
+///
+/// @example scss
+///   _retrieve-neat-setting($neat-grid)
+///
+/// @access private
+
+@function _neat-merge-defaults($grid) {
+  $_merged-grid: map-merge((
+    columns: 12,
+    gutter: 20px,
+    media: null,
+    color: rgba(#00d4ff, 0.25),
+    direction: ltr,
+  ), $grid);
+
+  @return $_merged-grid;
+}

core/neat/functions/_retrieve-neat-settings.scss

@@ -14,14 +14,6 @@
 /// @access private
 
 @function _retrieve-neat-setting($grid, $setting) {
-  $_neat-grid-defaults: map-merge((
-    columns: 12,
-    gutter: 20px,
-    media: null,
-    color: rgba(#00d4ff, 0.25),
-    direction: ltr,
-  ), $neat-grid);
-
-  $_grid-settings: map-merge($_neat-grid-defaults, $grid);
+  $_grid-settings: map-merge(_neat-merge-defaults($neat-grid), $grid);
   @return map-get($_grid-settings, $setting);
 }

core/neat/mixins/_grid-media.scss

@@ -50,7 +50,7 @@
 
   @media #{$_query} {
     $_default-neat-grid: $neat-grid;
-    $neat-grid: $grid !global;
+    $neat-grid: map-merge($neat-grid, $grid) !global;
     @content;
     $neat-grid: $_default-neat-grid !global;
   }