For generating a better look django offline docs follow the official guide
The original offline django DOCs which generated by Sphinx is somehow ugly. I've made some change to part of the template/css files.
Just follow the official guide to generate the offline doc as shown in: https://docs.djangoproject.com/en/3.0/internals/contributing/writing-documentation/
After you have generated the doc files in _build directory. Unzip the package and replace them in: Location_your_django_source_code/django-master/docs/_build/html/_static