.blink {
    -moz-animation: blink 1s step-end infinite;
    -o-animation: blink 1s step-end infinite;
    -webkit-animation: blink 1s step-end infinite;
    animation: blink 1s step-end infinite;
}
@-moz-keyframes blink {
    67% { opacity: 0 }
}
@-o-keyframes blink {
    67% { opacity: 0 }
}
@-webkit-keyframes blink {
    67% { opacity: 0 }
}
@keyframes blink {
    67% { opacity: 0 }
}