diff --git a/themes/oni/css/style.css b/themes/oni/css/style.css
index 902c68d..d7972cb 100644
--- a/themes/oni/css/style.css
+++ b/themes/oni/css/style.css
@@ -100,5 +100,6 @@ pre.src-makefile:before { content: 'Makefile'; }
 pre.src-makefile-gmake:before { content: 'GNUMakefile'; }
 pre.src-python:before { content: 'Python'; }
 pre.src-scheme:before { content: 'Scheme'; }
+pre.src-ruby:before { content: 'Ruby'; }
 
 #text-footnotes { float: left; clear: left; padding-right: 0.5em; }