diff --git a/docs/requirements.txt b/docs/requirements.txt
index 3b6de1f..a68922a 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -3,3 +3,5 @@ structlog
 appdirs
 tornado>=6
 sphinx>=3.2
+# <5 has strange bottom margins for p, and no list indicators
+sphinx-rtd-theme>=0.5