Source/devtools/front_end/source_frame/resourceSourceFrame.css

/*
 * Copyright (c) 2014 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.
 */

.resource-source-frame-fallback {
    background-color: #eee;
    word-wrap: break-word;
    white-space: pre-wrap;
    -webkit-user-select: text;
    overflow: auto;
}