Add UserBox

src/core/client/embed/index.html

@@ -6,6 +6,12 @@
   <meta charset="utf-8">
   <meta http-equiv="Content-type" content="text/html; charset=utf-8" />
   <meta name="viewport" content="width=device-width, user-scalable=no">
+  <style>
+    body {
+      margin: 0;
+      padding: 0;
+    }
+  </style>
 </head>
 
 <body>