diff --git a/doc-source/requirements.txt b/doc-source/requirements.txt
index 589ec62..b4ff7cf 100644
--- a/doc-source/requirements.txt
+++ b/doc-source/requirements.txt
@@ -2,7 +2,7 @@ git+https://github.com/domdfcoding/sphinx-click.git
 git+https://github.com/sphinx-toolbox/sphinx-toolbox-experimental.git
 default-values>=0.6.0
 extras-require>=0.5.0
-furo>=2020.11.19b18
+furo==2021.06.18b36
 html-section>=0.3.0
 seed-intersphinx-mapping>=1.2.2
 sphinx<3.4.0,>=3.0.3