diff --git a/tools/validator.html b/tools/validator.html
index ab142c6c..c52f3100 100644
--- a/tools/validator.html
+++ b/tools/validator.html
@@ -1,24 +1,38 @@
+<!DOCTYPE html>
 <html>
   <head>
     <!-- Note this code is pretty fugly, it needs to be rewritten -->
     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
     <style>
-      #descr {
+      body {
+        font-family: 'Verdana', sans-serif;
+        color: #333;
+        background-color: #f4f4f4;
+        padding: 20px;
+        font-size: 16px;
         width: 42em;
       }
       input[type="submit"] {
-        font-size: 1.2em;
+        font-size: 1.2rem;
         border-radius: 5px;
         border: 1px solid black;
         margin-top: 1ex;
+        padding: 10px;
+      }
+      textarea {
+        width: 100%;
+        height: 22rem;
+        font-family: monospace;
       }
 
       hr {
-        border: 1px solid black;
+        border: 1px solid #999;
+        margin: 0;
       }
     </style>
-    <script type="text/javascript" src="https://unpkg.com/ical.js"></script>
-    <script type="text/javascript">
+    <script type="module">
+      import ICAL from "https://unpkg.com/ical.js";
+
       function stringError(e) {
         return "Error: " + e +
                ("fileName" in e ? "\nFilename: " + e.fileName : "") +
@@ -26,7 +40,7 @@
                ("stack" in e ? "\nStack: " + e.stack : "");
       }
 
-      function validate() {
+      window.validate = function validate() {
         var duration = document.getElementById("duration");
 
         var data = document.getElementById("data");
@@ -40,7 +54,7 @@
 
         var beginTime = Date.now();
 
-        var jcal, from;
+        var jcal, ical, from;
         try {
             jcal = JSON.parse(data.value);
             from = "json";
