gecko-dev/browser/base/content/browser.css

searchbar {
  -moz-binding: url("chrome://browser/content/search/search.xml#searchbar");
}

tabbrowser {
  -moz-binding: url("chrome://browser/content/tabbrowser.xml#tabbrowser");
}

toolbar[printpreview="true"] {
  -moz-binding: url("chrome://global/content/printPreviewBindings.xml#printpreviewtoolbar");
}

/* ::::: location bar ::::: */
#urlbar {
  -moz-binding: url(chrome://browser/content/urlbarBindings.xml#urlbar);
}

#PopupAutoComplete {
  -moz-binding: url("chrome://browser/content/urlbarBindings.xml#browser-autocomplete-result-popup");
}

#PopupAutoCompleteRichResult {
  -moz-binding: url("chrome://browser/content/urlbarBindings.xml#urlbar-rich-result-popup");
}

menuitem.spell-suggestion {
  font-weight: bold;
}

#sidebar-box toolbarbutton.tabs-closebutton {
  -moz-user-focus: normal;
}

.verifiedDomain > hbox > #identity-icon-label {
  display: none;
}

/* apply Fitts' law to the notification bar's close button */
window[sizemode="maximized"] #content .notification-inner {
  border-right: 0px !important;
}

/* Hide extension toolbars that neglected to set the proper class */
window[chromehidden~="location"][chromehidden~="toolbar"] toolbar:not(.chromeclass-menubar),
window[chromehidden~="toolbar"] toolbar:not(.toolbar-primary):not(.chromeclass-menubar) {
  display: none;
}

#navigator-toolbox ,
#status-bar ,
#mainPopupSet {
  min-width: 1px;
}

#FindToolbar {
  overflow-x: hidden;
}