diff --git a/docs/requirements.txt b/docs/requirements.txt
index 3dac536..08d5cd6 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -4,7 +4,7 @@
 # generated by Doxygen (a system package — install separately, e.g.
 # `apt-get install doxygen`) and bridged into Sphinx with Breathe.
 Sphinx==9.1.0
-pydata-sphinx-theme==0.20.0
+pydata-sphinx-theme==0.21.0
 myst-parser==5.1.0
 sphinx-design==0.7.0
 breathe==4.36.0