🐛 fix(setup): remove hard-coded custom.css reference

The extension unconditionally added a custom.css stylesheet reference
that it never provided, causing 404 errors on themes that don't ship
their own custom.css.

Fixes #82

Author: gaborbernat

src/sphinx_argparse_cli/__init__.py

@@ -11,8 +11,6 @@
 
 
 def setup(app: Sphinx) -> dict[str, Any]:
-    app.add_css_file("custom.css")
-
     from ._logic import SphinxArgparseCli  # noqa: PLC0415
 
     app.add_directive(SphinxArgparseCli.name, SphinxArgparseCli)