gecko-dev/xpfe/browser/resources/content/navigator.css

/* ::::: Hide the link toolbar if it is set to autohide and has no items. ::::: */

#linktoolbar[hidden="maybe"][hasitems="false"]
{
  display: none;
}

/* ::::: urlbar autocomplete ::::: */

#urlbar {
  -moz-binding: url("chrome://navigator/content/urlbarBindings.xml#urlbar");
}

.autocomplete-result-popup[for="urlbar"] {
  -moz-binding: url("chrome://navigator/content/urlbarBindings.xml#autocomplete-result-popup") !important;
}

.autocomplete-search-box {
  -moz-binding: url("chrome://navigator/content/urlbarBindings.xml#autocomplete-search-box");
}

.autocomplete-search-engine {
  -moz-binding: url("chrome://navigator/content/urlbarBindings.xml#autocomplete-search-engine");
}