Firefox CSS to move tabs and adress bar to bottom of window. Use with Stylish or userChrome.css (works with Firefox 57+)

tabs_to_bottom.css

@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);

/* tabs to bottom */
#browser-panel { /* Deprecated since FF 59 */
	-moz-box-direction: reverse;
	padding: 0 !important;
}

#navigator-toolbox {
  -moz-box-ordinal-group: 2;
}

#main-window[sizemode="maximized"] {
	padding-top: 0 !important;
}

/* hide tab toolbar when fullscreen */
#nav-bar[inFullscreen],
#TabsToolbar[inFullscreen] {
	display: none !important;
}

/* hide titlebar */
#titlebar {
	display: none !important;
}

/* put suggestions popup on top */
#PopupAutoCompleteRichResult {
	opacity: 0.9;
	margin-top: -332px;
	margin-left: 10px;
	height: 300px;
}

#PopupAutoCompleteRichResult .autocomplete-richlistbox > scrollbox {
	overflow-y: auto !important;
}

/* or hide suggestions completely */
#PopupAutoCompleteRichResult { display: none; }

/* always hide tab toolbar */
#TabsToolbar {
  visibility: collapse !important;
}