Improve portal mobile responsiveness

cezen-portal/settings.html

@@ -64,6 +64,14 @@
     #toast { position:fixed; bottom:24px; right:24px; padding:12px 20px; border-radius:10px; font-size:14px; font-weight:600; display:none; z-index:999; }
     #toast.success { background:rgba(34,197,94,.15); color:#15803D; border:1px solid rgba(134,239,172,.3); }
     #toast.error   { background:rgba(185,28,28,.08); color:#B91C1C; border:1px solid rgba(239,68,68,.25); }
+    @media(max-width:640px){
+      .settings-grid,
+      .form-row { grid-template-columns:1fr; }
+      .settings-card,
+      .sessions-card,
+      .sysinfo-card { padding:22px; }
+      .logo-area { flex-direction:column; }
+    }
   </style>
 </head>
 <body data-role="admin">