Add log out button

assets/page.erb

@@ -110,10 +110,36 @@
     button:hover {
       background: #166534;
     }
+
+    .logout-form {
+      position: fixed;
+      top: 1rem;
+      right: 1rem;
+    }
+
+    .logout-btn {
+      width: auto;
+      padding: 0.4rem 0.8rem;
+      margin: 0;
+      background: #1e2433;
+      color: #94a3b8;
+      font-size: 0.75rem;
+    }
+
+    .logout-btn:hover {
+      background: #2a3040;
+    }
   </style>
 </head>
 <body>
 
+<% if authenticated %>
+  <form method="post" class="logout-form">
+    <input type="hidden" name="action" value="logout">
+    <button type="submit" class="logout-btn">Log Out</button>
+  </form>
+<% end %>
+
 <header>
   <h1><span><%= hostname %></span> status - MALP</h1>
 </header>