--- a/test/header.html	Thu Nov 10 18:44:48 2016 +0100
+++ b/test/header.html	Mon Apr 24 20:54:38 2023 +0200
@@ -3,6 +3,10 @@
   <head>
     <title>c2html</title>
     <style type="text/css">
+      div.c2html-code {
+        white-space: pre;
+        font-family: monospace;
+      }
       a.c2html-lineno {
         /* as long as user-select isn't widely spread, we throw the bomb */
         -webkit-user-select: none;