Make shift() reset nesting context

app/assets/stylesheets/grid/_grid.scss

@@ -100,6 +100,9 @@ $container-display-table: false;
 // Shift
 @mixin shift($n-columns: 1) {
   margin-left: $n-columns * flex-grid(1, $parent-columns) + $n-columns * flex-gutter($parent-columns);
+
+  // Reset nesting context
+  $parent-columns: $grid-columns;
 }
 
 

spec/neat/shift_spec.rb

@@ -24,4 +24,14 @@
       expect('.shift-negative').to have_rule('margin-left: -25.58941%')
     end
   end
+
+  context "when nested" do
+    it "shifts element relative to its parent" do
+      expect('.shifted-parent .shifted-child').to have_rule('margin-left: 34.94305%')
+    end
+
+    it "resets nesting context" do
+      expect('.post-nested-shift').to have_rule('margin-left: 17.05961%')
+    end
+  end
 end

test/shift.scss

@@ -11,3 +11,17 @@
 .shift-negative {
   @include shift(-3);
 }
+
+// Nesting
+.shifted-parent {
+  @include span-columns(6);
+
+  .shifted-child {
+    @include span-columns(2 of 6);
+    @include shift(2);
+  }
+}
+
+.post-nested-shift {
+  @include shift(2);
+}