diff --git a/src/core/include/mp-units/framework/unit_magnitude_concepts.h b/src/core/include/mp-units/framework/unit_magnitude_concepts.h
index 0204f327..be055212 100644
--- a/src/core/include/mp-units/framework/unit_magnitude_concepts.h
+++ b/src/core/include/mp-units/framework/unit_magnitude_concepts.h
@@ -54,7 +54,7 @@ struct unit_magnitude;
 template<typename T>
 constexpr bool is_mag_constant = detail::SymbolicConstant<T> && is_derived_from_specialization_of_v<T, mag_constant>;
 
-}
+}  // namespace detail
 
 /**
  * @brief  Concept to detect whether T is a valid UnitMagnitude.