Grey pre background on index

templates/index.html.tera

@@ -6,6 +6,11 @@
         margin: auto;
         max-width: 500px;
       }
+
+      pre {
+        background: #f5f5f5;
+        padding: 5px;
+      }
     </style>
     <meta name="viewport" content="width=device-width">
   </head>