Changes color scheme of alt keys.

ui/keyboard/resources/elements/kb-altkey.html

 <!--
   -- Copyright 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.
   -->
 
 <polymer-element name="kb-altkey" attributes="char" on-pointerover="{{over}}"
     on-pointerout="{{out}}" on-pointerup="{{up}}">
   <template>
     <style>
       :host {
         -webkit-box-flex: 1;
         background-position: center center;
         background-repeat: no-repeat;
         background-size: contain;
         display: -webkit-box;
         position: relative;
       }
 
       :host(.active) {
-        background-color: #afafaf;
+        background-color: #dddddd
       }
 
       :host(:first-child) {
         border-top-left-radius: 2px;
         border-bottom-left-radius: 2px;
       }
 
+      :host(:not(:first-child)) .key{
+        border-left: solid 2px #dddddd;
+      }
+
       :host(:last-child) {
         border-top-right-radius: 2px;
         border-bottom-right-radius: 2px;
       }
 
       :host .key {
         bottom: 0;
-        color: #ffffff;
+        color: #666666;
         font-family: roboto-bold;
         font-weight: 100;
         height: 1.2em;
         left: 0;
         margin: auto;
         position: absolute;
         right: 0;
         top: 0;
         text-align: center;
       }
     </style>
     <div class="key">
       <content></content>
     </div>
   </template>
 </polymer-element>