body {
    padding-top:250px;
    padding-left:250px;
}
.heart {
    background-color: crimson;
    display: inline-block;
    width: 100px;
    height: 100px;
    position: relative;
    top: 0;
    transform: rotate(-45deg);
    position: absolute;
    left: 45%;
    top: 45%;
    animation: heartbeat 1.25s infinite;
}

    .heart::before,
    .heart::after {
        content: "";
        background-color: crimson;
        width: 100px;
        height: 100px;
        border-radius: 50%;
        position: absolute;
        animation: pulsecolor 1.25s infinite;
    }

    .heart::before {
        top: -50px;
        left: 0;
    }

    .heart::after {
        top: 0;
        left: 50px;
    }

@keyframes heartbeat {
    0% {
        transform: scale(1) rotate(-45deg);
    }

    10% {
        transform: scale(1.25) rotate(-45deg);
        background-color: #EF395E;
    }

    100% {
        transform: scale(1) rotate(-45deg);
    }
}

@keyframes pulsecolor {
    10% {
        background-color: #EF395E;
    }
}