diff --git a/docs/source/conf.py b/docs/source/conf.py
index c21ec0b..e6851a6 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -19,7 +19,8 @@
     'sphinx.ext.intersphinx',
     'sphinx.ext.todo',
     'myst_parser',
-    'nbsphinx'
+    'nbsphinx',
+    'sphinx_rtd_theme'
 ]
 
 intersphinx_mapping = {
diff --git a/docs/source/requirements.txt b/docs/source/requirements.txt
index 7b1889b..100eebd 100644
--- a/docs/source/requirements.txt
+++ b/docs/source/requirements.txt
@@ -1,2 +1,3 @@
+sphinx_rtd_theme
 myst-parser
 nbsphinx