chrome/browser/resources/user_actions/user_actions.css

/* Copyright 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. */

thead {
  white-space: nowrap;
}

th {
  background-color: #C0C0C0;
}

td {
  background-color: #F0F0F0;
}