diff --git i/Documentation/conf.py w/Documentation/conf.py
index 6a767294887e..d1d145759fed 100644
--- i/Documentation/conf.py
+++ w/Documentation/conf.py
@@ -267,11 +267,9 @@ except ImportError:
 
 html_static_path = ['sphinx-static']
 
-html_context = {
-    'css_files': [
-        '_static/theme_overrides.css',
-    ],
-}
+html_css_files = [
+    '_static/theme_overrides.css',
+]
 
 # Add any extra paths that contain custom files (such as robots.txt or
 # .htaccess) here, relative to this directory. These files are copied