Clean up managed user settings dialogs.

chrome/browser/resources/managed_user_passphrase_dialog.css

 /* Copyright (c) 2013 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
 #managed-mode-passphrase-page {
   min-width: 350px;
+  padding: 5px 15px;
 }
 
 #managed-user-logo {
   background-image: url('options/managed_user.png');
   height: 68px;
   width: 65px;
 }
 
-#instructions,
-#entry,
-#incorrect-passphrase-warning {
-  padding: 5px 15px;
+#entry {
+  margin: 15px 0;
+}
+
+#passphrase-entry {
+  width: 100%;
 }
 
 #buttons {
   float: right;
 }
 
 html[dir=rtl] #buttons {
   float: left;
 }
 
-#buttons {
-  padding: 15px 15px;
-}
-
 #incorrect-passphrase-warning {
   color: red;
   font-weight: bold;
 }