diff --git a/gnes/resources/static/gnes-board.html b/gnes/resources/static/gnes-board.html
index 86828d32..ef704b79 100644
--- a/gnes/resources/static/gnes-board.html
+++ b/gnes/resources/static/gnes-board.html
@@ -6,7 +6,7 @@
+ href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.15.8/styles/default.min.css">