Fix misplacement of PIN keyboard and sign-in banner for new login screen

ui/login/account_picker/md_screen_account_picker.css

 /* Copyright 2014 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.
  */
 
 .account-picker.flying-pods #account-picker {
   transition: width 180ms ease, height 180ms ease;
 }
 
 #bubble {
@@ skipping 28 matching lines @@
   position: relative;
   text-align: center;
 }
 
 html[dir=rtl] #signin-banner {
   left: auto;
   right: -50%;
 }
 
 html[screen=user-adding] #signin-banner {
+  background-color: rgba(0, 0, 0, 0.34);
   display: inline-block;
 }
 
+html[screen=user-adding] #signin-banner,
 html[screen=login] #signin-banner {
   padding: 20px 24px;
 }
 
 html[screen=login] #signin-banner,
 html[screen=lock] #signin-banner {
   display: inline-block;
   opacity: 0;
   visibility: hidden;
 }
@@ skipping 31 matching lines @@
   background: linear-gradient(#4FC3F7, transparent);
   height: 112px;
   position: absolute;
   width: 100%;
   z-index: 2;
 }
 
 .small-pod-container-mask.rotate {
   transform: rotate(180deg);
 }