@evidentpoint/readium-css/docs/ua-reference/ua-stylesheets/gecko-firefox/plaintext.css

A set of reference stylesheets for EPUB Reading Systems

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

pre {
  white-space: pre-wrap;
  word-wrap: break-word;
  -moz-control-character-visibility: visible;
}

/* Make text go with the rules of dir=auto, but allow it to be overriden if 'Switch Text Direction' is triggered */
html:not([dir]) pre {
  unicode-bidi: plaintext;
}