@keyframes heartbeat {
    0% {
        transform: scaleY(1.4) scaleX(1.6);
        filter: brightness(0.9) drop-shadow(0px 0px 0.3rem rgb(255, 255, 255));
    }

    25% {
        transform: scaleY(1.6) scaleX(2);
        filter: brightness(1.25) drop-shadow(0px 0px 0.6rem rgb(255, 0, 0));
    }

    75% {
        transform: scaleY(1.2) scaleX(1.8);
        filter: brightness(1) drop-shadow(0px 0px 0.4rem rgb(255, 255, 255));
    }

    100% {
        transform: scaleY(1.4) scaleX(1.6);
        filter: brightness(0.8) drop-shadow(0px 0px 0.2rem rgba(255, 255, 255, 0));
    }
}