diff --git a/eternity/meta.json b/eternity/meta.json
index fbb6a25..619ef42 100644
--- a/eternity/meta.json
+++ b/eternity/meta.json
@@ -7,6 +7,7 @@
   "localization": false,
   "config": {
     "product_name": "eternityproject.fi",
-    "favicon": "/images/favicon.svg"
+    "favicon": "/images/favicon.svg",
+    "skin_logo": "/images/logo.svg"
   }
 }
diff --git a/eternity/styles/styles.css b/eternity/styles/styles.css
index a3cba25..dfb77f9 100644
--- a/eternity/styles/styles.css
+++ b/eternity/styles/styles.css
@@ -1,4 +1,9 @@
+/* The official roundcube/roundcubemail Docker image ships Elastic pre-minified
+   as styles.min.css (no plain styles.css); source/dev installs may have only
+   the unminified file. A missing @import just yields an empty sheet, so
+   importing both here is a harmless way to support either layout. */
 @import url("../../elastic/styles/styles.css");
+@import url("../../elastic/styles/styles.min.css");
 
 :root {
   --ink: #11212b;
diff --git a/eternity/watermark.html b/eternity/watermark.html
new file mode 100644
index 0000000..e374451
--- /dev/null
+++ b/eternity/watermark.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="UTF-8">
+<title></title>
+<style type="text/css">
+html, body { height: 100%; overflow: hidden; }
+body {
+  background: url(images/logo.svg) center no-repeat #f1f1e9;
+  background-size: 30%;
+}
+html:not(.dark-mode) body:before {
+  content: "";
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  left: 0;
+  right: 0;
+  background: rgba(241, 241, 233, .85);
+}
+html.dark-mode > body {
+  background-color: #11212b;
+}
+</style>
+<script>
+  try {
+    if (document.cookie.indexOf('colorMode=dark') > -1
+      || (document.cookie.indexOf('colorMode=light') === -1 && window.matchMedia('(prefers-color-scheme: dark)').matches)
+    ) {
+      document.documentElement.className += ' dark-mode';
+    }
+  } catch (e) { }
+</script>
+</head>
+<body></body>
+</html>
