diff --git a/mkdocs.yml b/mkdocs.yml
index 30152c1..18210bd 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -1,5 +1,11 @@
 site_name: "redo: a recursive build system"
-theme: readthedocs
+theme:
+  name: readthedocs
+  hljs_languages:
+    - python
+    - r
+    - shell
+    - tex
 docs_dir: docs
 site_dir: docs.out
 strict: true