Remove double slash in path (#311)

diff --git a/sphinx_airflow_theme/sphinx_airflow_theme/__init__.py b/sphinx_airflow_theme/sphinx_airflow_theme/__init__.py
index 2dc7265..11cb41b 100644
--- a/sphinx_airflow_theme/sphinx_airflow_theme/__init__.py
+++ b/sphinx_airflow_theme/sphinx_airflow_theme/__init__.py
@@ -52,5 +52,5 @@
     )
 
     app.add_html_theme('sphinx_airflow_theme', path.abspath(path.dirname(__file__)))
-    app.add_stylesheet('_gen/css//main-custom.min.css')
+    app.add_stylesheet('_gen/css/main-custom.min.css')
     app.connect("html-page-context", setup_my_func)