Fix offset class in config

Author: gabsource

src/config/config.php

@@ -30,7 +30,7 @@
     'left_column_class' => 'col-sm-2 col-md-3',
     'right_column_class' => 'col-sm-3 col-md-9',
 
-    'left_column_offset_class' => 'col-sm-offset-2 col-md-offset-3',
+    'left_column_offset_class' => 'offset-sm-2 offset-md-3',
 
     /*
     |--------------------------------------------------------------------------