diff --git a/lib/ace/theme/cobalt.css b/lib/ace/theme/cobalt.css
index 16568fc3..73140082 100644
--- a/lib/ace/theme/cobalt.css
+++ b/lib/ace/theme/cobalt.css
@@ -5,7 +5,7 @@
 
 .ace-cobalt .ace_print-margin {
   width: 1px;
-  background: #011e3a
+  background: #555555
 }
 
 .ace-cobalt {
@@ -131,4 +131,4 @@
 
 .ace-cobalt .ace_indent-guide {
   background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAACCAYAAACZgbYnAAAAEklEQVQImWNgYGBgYHCLSvkPAAP3AgSDTRd4AAAAAElFTkSuQmCC) right repeat-y
-}
\ No newline at end of file
+}