diff --git a/doc/source/conf.py b/doc/source/conf.py
index cfcbd563b..1f846fc08 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -59,7 +59,6 @@ def setup(app):
     app.add_config_value('prolog_replacements', {}, True)
     app.connect('source-read', prologReplace)
     app.connect("autodoc-process-docstring", remove_module_docstring)
-    app.add_css_file('css/custom.css')
 
 
 prolog_replacements = {