body {
    background-color: black;
    margin: 0;
    height: 100vh;
    overflow: hidden;
}

span {
    background: url("https://cdn2.iconfinder.com/data/icons/free-1/128/Love__heart_like-512.png");
    width: 100px;
    height: 100px;
    position: absolute;
    pointer-events: none;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    background-size: cover; 
    animation: animate 6s linear;
}

/* animating the heart icon to change its postion 
continously in the top direction
*/
@keyframes animate {
    0% {
        transform: translate(-50%, -50%);
        opacity: 1;
        filter: hue-rotate(0);
    } 

    100% {
        transform: translate(-50%, -5000%);
        opacity: 100;
        filter: hue-rotate(720deg);
    }
}