diff --git a/doc/Pipfile b/doc/Pipfile
index c6652a78d2a..a522ec87ed6 100644
--- a/doc/Pipfile
+++ b/doc/Pipfile
@@ -23,7 +23,12 @@ verify_ssl = true
 
 [packages]
 
-sphinx = "*"
+# The latest 4.x sphinx release has issues with style rendering. The 3.x
+# releases build and render fine, however. So we currently pin to that.
+#
+# Once that issue, either with sphinx or our docs, is resolved, then we should
+# unpin sphinx by setting the following to "*".
+sphinx = "==3.*"
 
 sphinx-rtd-theme = "*"
 sphinxcontrib-plantuml = "*"
diff --git a/doc/conf.py b/doc/conf.py
index d8a77fdef3f..6d779d052ef 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -280,7 +280,6 @@ def issue_reference(self, match, lineno):
 # content wrapping.
 html_context = {
     'css_files': [
-        '_static/css/theme.css',
         '_static/override.css'
     ]
 }