gecko-dev/browser/themes/windows/searchbar.css

/* 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/. */

%include ../shared/searchbar.inc.css

.searchbar-engine-one-off-item:-moz-focusring {
  outline: none;
}

@media (-moz-proton) and (-moz-os-version: windows-win10) {
  #PopupSearchAutoComplete {
    /* A border is necessary because the shadow is bottom-right */
    border-color: var(--menu-border-color);
    border-radius: var(--arrowpanel-border-radius);
    -moz-window-shadow: cliprounded;
  }
}