gecko-dev/layout/style/TopLevelVideoDocument.css

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */

/*
  This CSS stylesheet defines the rules to be applied to VideoDocuments that
  are top level (e.g. not iframes).
*/

body {
  height: 100%;
  width: 100%;
  margin: 0;
  padding: 0;
  -moz-user-focus: ignore;
}

video {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  margin: auto;
  max-width: 100%;
  max-height: 100%;
  -moz-user-select: none;
  -moz-user-focus: normal;
}

video:focus {
  outline-width: 0;
}