diff --git a/index.php b/index.php
index 2ebc7fd..5a91d1b 100644
--- a/index.php
+++ b/index.php
@@ -84,6 +84,8 @@ if ($index === false) {
     exit();
 }
 
+$light = filter_var($_GET['light'] ?? false, FILTER_VALIDATE_BOOLEAN);
+
 $total = count($sites);
 $prev = $sites[($index - 1 + $total) % $total];
 $next = $sites[($index + 1) % $total];