Tooltip (originally based on code from http://stackoverflow.com/questions/5623072/css-craziness-and-a-new-challenge/5633146#5633146)

gistfile1.css

.tooltip {
    font: 14px Helevetica, sans-serif;
    line-height: 18px;
    position: relative;
    border: 2px solid #73a7f0;
    max-width: 200px;
    margin-left: 20px;
    padding: 5px 14px;
    border-radius: 4px;
    -webkit-border-radius: 4px;
    -moz-border-radius: 4px;
    box-shadow: 0px 0px 4px rgba(0, 0, 0, .7);
    -webkit-box-shadow: -0px 0px 4px rgba(0, 0, 0, .7);
    -moz-box-shadow: 0px 0px 4px rgba(0, 0, 0, .7);
    color: black;
    text-decoration: none;
    display: inline-block
}
.tooltip:before {
    content: " ";
    display: block;
    position: absolute;
    left: -8px;
    top: 8px;
    width: 12px;
    height: 12px;
    border-color: #73a7f0;
    border-width: 2px;
    border-style: none none solid solid;
    background-color: #fff;
    box-shadow: -2px 2px 2.5px rgba(0, 0, 0, .3);
    -webkit-box-shadow: -2px 2px 2.5px rgba(0, 0, 0, .3);
    -moz-box-shadow: -2px 2px 2.5px rgba(0, 0, 0, .3);
    transform: rotate(45deg);
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
}