Sphinx: How set the right path for html_static_path in config.py?
The build directory is created after you build the docs, which is why you get that error. When you make your docs, Sphinx will copy the static directory from your source location as defined by html_static_path to the build location.
Create a new directory source/_static and place any static assets inside of it.
Change the value in conf.py to this:
html_static_path = ["_static"]