diff --git a/broadcast/index.frm.php b/broadcast/index.frm.php
index 34a1937..9eda476 100644
--- a/broadcast/index.frm.php
+++ b/broadcast/index.frm.php
@@ -9,7 +9,7 @@
         <script src="//ajax.googleapis.com/ajax/libs/jqueryui/1/i18n/jquery.ui.datepicker-ja.min.js"></script>
         <link href="//cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-T3c6CoIi6uLrA9TneNEoa7RxnatzjcDSCmG1MXxSR1GAsXEV/Dwwykc2MPK8M2HN" crossorigin="anonymous" />
         <link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.12.1/themes/base/jquery-ui.min.css" />
-        <link href="./style.css" rel="stylesheet" />
+        <link href="./style.css?<?= filemtime('./style.css') ?>" rel="stylesheet" />
         <?php $april_fool = ((int) date ('n') === 4) && ((int) date ('j') === 1) ?>
         <?php if ($april_fool): ?>
             <link rel="icon" href="favicon-goatoh.ico" />