chrome/browser/resources/history/alert_overlay.css

/* 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. */

.overlay .page .button-strip > button {
  min-width: 7em;
}

.overlay {
  z-index: 4;
}

#alertOverlayMessage {
  width: 400px;
}

#alertOverlayMessage {
  white-space: pre-wrap;
  word-wrap: break-word;
}