Dropping files into the root list.

chrome/browser/resources/file_manager/css/file_manager.css

 /* Copyright (c) 2012 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. */
 
 html.col-resize * {
   cursor: col-resize !important;
 }
 
 /* Outer frame of the dialog. */
 body {
@@ skipping 205 matching lines @@
 
 list.roots-list > * {
   background-color: #e6e6e6;
   border: none;
   border-radius: 0;
   height: 39px;
   margin: 0;
   padding: 0 5px;
 }
 
+list.roots-list > .accepts,
 list.roots-list > [lead][selected],
 list.roots-list > [lead],
 list.roots-list > [selected],
 list.roots-list > [anchor] {
   background-color: rgb(204, 219, 243);
   background-image: none;
   border-bottom: 1px solid rgb(195, 210, 233);
   border-top: 1px solid rgb(195, 210, 233);
   height: 37px;
 }
 
+list.roots-list > .accepts:hover,
 list.roots-list > [lead]:hover,
 list.roots-list > [lead][selected]:hover,
 list.roots-list > [selected]:hover,
 list.roots-list > [anchor]:hover {
   background-color: rgb(193, 211, 236) !important;
   border-bottom: 1px solid transparent !important;
   border-top: 1px solid transparent !important;
   height: 37px !important;
 }
 
@@ skipping 903 matching lines @@
 }
 
 body[ash] .dialog-title,
 body[type='full-page'] [invisibleif='full-page'],
 body:not([type='full-page']) [visibleif='full-page'],
 body:not([type='saveas-file']) [visibleif='saveas-file'],
 body:not([type='saveas-file']):not([type='full-page'])
     [visibleif='saveas-file full-page'] {
   display: none;
 }