diff -up ./docs/conf.py.orig ./docs/conf.py
--- ./docs/conf.py.orig	2020-12-22 10:43:42.000000000 +0100
+++ ./docs/conf.py	2021-01-18 06:37:18.679269871 +0100
@@ -90,7 +90,7 @@ github_project = 'streamlink/streamlink'
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'furo'
+html_theme = 'sphinx_rtd_theme'
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the