@keyframes border-pulse {
    0% {
        border-color: rgba(0, 255, 255, 1);
    }

    50% {
        border-color: rgba(0, 255, 255, 0);
    }

    100% {
        border-color: rgba(0, 255, 255, 1);
    }
}

.pulse {
    display: block;
    /*margin: 20px auto;*/
    border: 8px solid cyan;
    animation: border-pulse 2s infinite;
}