diff --git a/api-viewer/index.html b/api-viewer/index.html
index 346fa38..4d708ef 100644
--- a/api-viewer/index.html
+++ b/api-viewer/index.html
@@ -6,6 +6,7 @@
     <title>Proxmox Mail Gateway API Documentation</title>
 
     <link rel="stylesheet" type="text/css" href="extjs/theme-crisp/resources/theme-crisp-all.css">
+    <link rel="stylesheet" type="text/css" media="(prefers-color-scheme: dark)" href="/pwt/themes/theme-proxmox-dark.css" />
     <script type="text/javascript" src="extjs/ext-all.js"></script>
     <script type="text/javascript" src="apidoc.js"></script>
 </head>