.heartbeat {
    animation: heartbeat 1.5s linear 0.5s infinite;
}

@keyframes heartbeat {
    0% {
        -webkit-transform: scale(1);
        transform: scale(1)
    }

    14% {
        -webkit-transform: scale(1.3);
        transform: scale(1.3)
    }

    28% {
        -webkit-transform: scale(1);
        transform: scale(1)
    }

    42% {
        -webkit-transform: scale(1.3);
        transform: scale(1.3)
    }

    70% {
        -webkit-transform: scale(1);
        transform: scale(1)
    }
}