🔧 MAINTAIN: Drop furo-specific stylesheet (#22)

Author: pradyunsg

docs/_static/sd-furo.css

@@ -44,9 +44,6 @@
     html_theme_options = {
         "sidebar_hide_name": True,
     }
-    html_css_files = [
-        "sd-furo.css",
-    ]
 if html_theme == "sphinx_rtd_theme":
     html_theme_options = {
         "logo_only": True,