Update documentation about custom properties

Fix #1616.
Kozea · Apr 3, 2022 · c17123c · c17123c
1 parent 56f0d4a
commit c17123c
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/docs/api_reference.rst b/docs/api_reference.rst
@@ -686,9 +686,11 @@ The `CSS Custom Properties for Cascading Variables Module Level 1`_ "introduces
 cascading variables as a new primitive value type that is accepted by all CSS
 properties, and custom properties for defining them."
 
-The custom properties and the ``var()`` notation are supported.
+The custom properties are supported. The ``var()`` notation is `only supported
+in single-value properties`_.
 
 .. _CSS Custom Properties for Cascading Variables Module Level 1: https://www.w3.org/TR/css-variables/
+.. _only supported in single-value properties: https://github.com/Kozea/WeasyPrint/issues/1219
 
 CSS Text Decoration Module Level 3
 ++++++++++++++++++++++++++++++++++