diff --git a/docs/superpowers/plans/2026-05-16-textarea-code-editor.md b/docs/superpowers/plans/2026-05-16-textarea-code-editor.md
index edc1bd9..80a52ef 100644
--- a/docs/superpowers/plans/2026-05-16-textarea-code-editor.md
+++ b/docs/superpowers/plans/2026-05-16-textarea-code-editor.md
@@ -625,6 +625,7 @@ def test_blueprint_detail_renders_editor_assets(user_client) -> None:
     assert 'data-editor-language="srccfg"' in body
     # All editor assets are referenced.
     assert "static/vendor/prism.js" in body
+    assert "static/vendor/prism.css" in body
     assert "static/vendor/codejar.js" in body
     assert "static/js/srccfg-grammar.js" in body
     assert "static/js/editor.js" in body
diff --git a/l4d2web/tests/test_blueprints.py b/l4d2web/tests/test_blueprints.py
index 103a608..1f9c10a 100644
--- a/l4d2web/tests/test_blueprints.py
+++ b/l4d2web/tests/test_blueprints.py
@@ -268,6 +268,7 @@ def test_blueprint_detail_renders_editor_assets(user_client) -> None:
     assert 'data-editor-language="srccfg"' in body
     # All editor assets are referenced.
     assert "static/vendor/prism.js" in body
+    assert "static/vendor/prism.css" in body
     assert "static/vendor/codejar.js" in body
     assert "static/js/srccfg-grammar.js" in body
     assert "static/js/editor.js" in body