diff --git a/themes/bluemarine/style.css b/themes/bluemarine/style.css
index 636ee3a010191d02b29b3c6e82f8ce3d0bd50ebf..a1f11b4bb31686b01fa1fe2700ef8c6973a314f1 100644
--- a/themes/bluemarine/style.css
+++ b/themes/bluemarine/style.css
@@ -14,7 +14,7 @@ tr.dark td, tr.light td {
   padding: 0.3em;
 }
 h1, h2, h3, h4, h5, h6 {
-  margin: 0.5;
+  margin: 0.5em;
 }
 h1 {
   font-size: 1.3em;