frappe/css/ui/status_bar.css

div.status_bar_outer {
	background-color: rgba(0,0,0,0.1);
	border: 1px solid rgba(0,0,0,0.4);
	height: 21px;
	width: 240px;
}

div.status_bar_inner {
	background: #aaf; /* Old browsers */
	height: 21px;
	width: 0%;
}