diff --git a/docs/source/conf.py b/docs/source/conf.py
index 6a6fc85..d4bb2e3 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -31,8 +31,11 @@
 
 html_theme = 'sphinx_rtd_theme'
 html_static_path = ['_static']
-def setup(app):
-    app.add_stylesheet('custom.css')
+html_context = {
+    'css_files': [
+        'css/custom.css',  # overrides for wide tables in RTD theme
+        ],
+    }
 
 html_logo = "logo_rect.png"
 html_theme_options = {'logo_only': False}
diff --git a/docs/source/_static/custom.css b/docs/source/css/custom.css
similarity index 100%
rename from docs/source/_static/custom.css
rename to docs/source/css/custom.css