added breakpint: null and removed deprecated !global

assets/sass/libs/_breakpoints.scss

@@ -4,7 +4,8 @@
 
 	/// Breakpoints.
 	/// @var {list}
-	$breakpoints: () !global;
+	//$breakpoints: () !global;
+	$breakpoints: null;
 
 // Mixins.
 
@@ -220,4 +221,4 @@
 				@content;
 			}
 
-	}
+	}