jsFiddle: http://jsfiddle.net/XrHcA/14/

led.css

body { padding: 50px; background-color: #f7f5fa; }
.led {
    margin: 20px auto;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.25);
    box-shadow: #000 0 -1px 6px 1px;
}
.led-red {
    background-color: #F00;
    box-shadow: #7D7B80 0 -1px 6px 1px, inset #600 0 -1px 8px, #F00 0 3px 11px;
}
.led-orange {
    background-color: #FF7000;
    box-shadow: #7D7B80 0 -1px 6px 1px, inset #630 0 -1px 8px, #FF7000 0 3px 11px;
}

.led-yellow {
    background-color: #FF0;
    box-shadow: #7D7B80 0 -1px 6px 1px, inset #660 0 -1px 8px, #FF0 0 3px 11px;
}

.led-green {
    background-color: #80FF00;
    box-shadow: #7D7B80 0 -1px 6px 1px, inset #460 0 -1px 8px, #80FF00 0 3px 11px;
}

.led-blue {
    background-color: #06F;
    box-shadow: #7D7B80 0 -1px 6px 1px, inset #006 0 -1px 8px, #06F 0 3px 11px;
}

led.html

<div class="led led-red"></div>
<div class="led led-yellow"></div>
<div class="led led-green"></div>
<div class="led led-blue"></div>