chrome/browser/resources/shared/css/alert_overlay.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. */

#alertOverlay {
  width: 500px;
}

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