Edit in JSFiddle

 <div id="lean_overlay" style="display: block; opacity: 1;"></div>

#lean_overlay {
		background: transparent;
		background-image: -webkit-radial-gradient(50% 30%,circle, rgba(0,0,0,0.4), rgba(0,0,0,0.6));
		background-image: radial-gradient(circle at 50% 30%, rgba(0,0,0,0.4), rgba(0,0,0,0.6));
		display: none;
		height: 100%;
		left: 0;
		position: fixed;
		top: 0;
		width: 100%;
		z-index: 100;
	}