diff --git a/docs/conf.py b/docs/conf.py
index f85cd187..d27c1fdc 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -265,6 +265,9 @@ html_static_path = ['_static']
 html_js_files = [
     'custom.js',
 ]
+html_css_files = [
+    'custom.css',
+]
 
 # Add any extra paths that contain custom files (such as robots.txt or
 # .htaccess) here, relative to this directory. These files are copied