Use responses for Flask directly
pip3 install dflaskpip3 install git+https://github.com/donno2048/Direct-Flaskfrom dflask import DirectFlask, Response
app = DirectFlask(__name__)
app.add_response("/", Response("<html><head><link href='/style.css' rel='stylesheet'></head><body></body></html>"))
app.add_response("/style.css", "body{background-color: red;}").run()