diff --git a/templates/index.html b/templates/index.html
index 6911ab2..5ee99b1 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -9,6 +9,8 @@
   <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-T3c6CoIi6uLrA9TneNEoa7RxnatzjcDSCmG1MXxSR1GAsXEV/Dwwykc2MPK8M2HN" crossorigin="anonymous">
   <link rel="icon" href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>📅</text></svg>">
 
+  <script async src="https://unpkg.com/es-module-shims@1.8.2/dist/es-module-shims.js"></script>
+
     <script type='importmap'>
       {
         "imports": {