diff --git a/docs/environment.yml b/docs/environment.yml
index 3ee9269..95190ca 100644
--- a/docs/environment.yml
+++ b/docs/environment.yml
@@ -5,3 +5,4 @@ channels:
 
 dependencies:
   - breathe
+  - sphinx_rtd_theme
diff --git a/docs/source/conf.py b/docs/source/conf.py
index 6619929..5fda74a 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -18,10 +18,8 @@
 def setup(app):
     app.add_css_file("main_stylesheet.css")
 
-extensions = [
-#'breathe'
-]
-# breathe_projects = { 'xeus-lua': '../xml' }
+extensions = ['breathe', 'sphinx_rtd_theme']
+breathe_projects = { 'xeus-lua': '../xml' }
 templates_path = ['_templates']
 html_static_path = ['_static']
 source_suffix = '.rst'
diff --git a/readthedocs.yml b/readthedocs.yml
index bf75118..38f414b 100644
--- a/readthedocs.yml
+++ b/readthedocs.yml
@@ -1,2 +1,9 @@
-sphinx:
-   configuration: docs/source/conf.py
+version: 2
+
+build:
+  os: "ubuntu-22.04"
+  tools:
+    python: "mambaforge-22.9"
+
+conda:
+  environment: docs/environment.yml