diff --git a/docs/css-classes-reference.rst b/docs/css-classes-reference.rst
index 8fceca3d8a..2a90185550 100644
--- a/docs/css-classes-reference.rst
+++ b/docs/css-classes-reference.rst
@@ -60,6 +60,8 @@ in mind so a better choice (for best theme support) might possibly be ``string``
 | variable.language        | variable with special meaning in a language, e.g.:          |
 |                          | ``this``, ``window``, ``super``, ``self``, etc.             |
 +--------------------------+-------------------------------------------------------------+
+| variable.constant        | variable that is a constant value, ie ``MAX_FILES``         |
++--------------------------+-------------------------------------------------------------+
 | title                    | name of a class or a function                               |
 +--------------------------+-------------------------------------------------------------+
 | title.class              | name of a class (interface, trait, module, etc)             |