diff --git a/themes/oni/css/style.css b/themes/oni/css/style.css
index f002d4c..109df70 100644
--- a/themes/oni/css/style.css
+++ b/themes/oni/css/style.css
@@ -105,6 +105,7 @@ 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'; }
+pre.src-dockerfile:before { content: 'Dockerfile'; }
 
 .footnum { float: left; clear: left; padding-right: 0.5em; }