.cuadrado {
    width: 80%;
    height: 90%;
    background: #428bca;
}

.parpadea {
    animation-name: parpadeo;
    animation-duration: 2s;
    animation-timing-function: linear;
    animation-iteration-count: infinite;
    -webkit-animation-name: parpadeo;
    -webkit-animation-duration: 2s;
    -webkit-animation-timing-function: linear;
    -webkit-animation-iteration-count: infinite;
}

@-moz-keyframes parpadeo {
    0% {
        opacity: 1.0;
    }

    50% {
        opacity: 0.0;
    }

    100% {
        opacity: 1.0;
    }
}

@-webkit-keyframes parpadeo {
    0% {
        opacity: 1.0;
    }

    50% {
        opacity: 0.0;
    }

    100% {
        opacity: 1.0;
    }
}

@keyframes parpadeo {
    0% {
        opacity: 1.0;
    }

    50% {
        opacity: 0.0;
    }

    100% {
        opacity: 1.0;
    }
}