diff --git a/public/demo-dark.html b/public/demo-dark.html
new file mode 100644
index 0000000..398911c
--- /dev/null
+++ b/public/demo-dark.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<html lang="">
+  <head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <script type="module">
+      function saveTextAsFile(text, filename) {
+        const elem = document.createElement('a');
+        elem.href = 'data:text/json;charset=utf-8,' + encodeURIComponent(text);
+        elem.download = filename;
+        elem.click();
+      }
+      const data = await fetch('example.json').then((res) => res.json());
+      data.settings.darkMode = true;
+      window.addEventListener('message', (event) => {
+        saveTextAsFile(JSON.stringify(event.data), 'response.json');
+      });
+      window.onload = () => {        
+        const iframe = document.getElementById('iframe');
+        iframe.contentWindow.postMessage(data, window.origin);
+      };
+    </script>
+    <style>
+      body {
+        font-family: Inter, 'Helvetica Neue', Helvetica, 'PingFang SC',
+          'Hiragino Sans GB', 'Microsoft YaHei', '微软雅黑', Arial, sans-serif;
+      }
+    </style>
+  </head>
+  <body>
+    <iframe
+      src="index.html"
+      style="width: 100%; height: 100%; border: none; position: absolute; top: 0; left: 0;"
+      id="iframe"></iframe>
+  </body>
+</html>
diff --git a/public/parent.html b/public/demo.html
similarity index 92%
rename from public/parent.html
rename to public/demo.html
index 3bd94d3..51f4cd3 100644
--- a/public/parent.html
+++ b/public/demo.html
@@ -29,7 +29,7 @@
   <body>
     <iframe
       src="index.html"
-      style="width: 99vw; height: 95vh; border: none;"
+      style="width: 100%; height: 100%; border: none; position: absolute; top: 0; left: 0;"
       id="iframe"></iframe>
   </body>
 </html>
