Blink Animation

CSS3 blinking animation

HTML

<div class="box"></div>

CSS

body { margin: 20px; }
.box {
    height: 100px;
    width: 100px;
    background: #000;
    box-shadow: 0 0 30px #666;
    border-radius: 50%;
    opacity: 1;
    -webkit-animation: blink 0.5s 0 infinite alternate forwards ease-in;
}

@-webkit-keyframes blink {
    from {
        opacity: 1;
    }
    to {
        opacity: 0.4;
    }
}