fade out tooltip

[budimir]

How to make this to fade out slowly when mouse moves out of link? It does show up slowly, but I need it to go out slowly also. I can't figure it out.

		.tooltip span {
			;
			position: absolute;
            visibility:hidden;
            opacity:0;
            transition:visibility 0s linear 0.5s,opacity 0.5s linear;
		}
		.tooltip:hover span {
			border-radius: 5px 5px; -moz-border-radius: 5px; -webkit-border-radius: 5px; 
			box-shadow: 5px 5px 5px rgba(0, 0, 0, 0.1); -webkit-box-shadow: 5px 5px rgba(0, 0, 0, 0.1); -moz-box-shadow: 5px 5px rgba(0, 0, 0, 0.1);
			font-family: Calibri, Tahoma, Geneva, sans-serif;
			position: absolute; left: 1em; top: 2em; z-index: 99;
			margin-left: 0; width: 250px;
            visibility:visible;
            opacity:1;
            transition-delay:0s;
            transition:visibility 0s linear 0.5s,opacity 0.5s linear;
		}