li{
    position: relative;
}

i{
    position: absolute;
    transform-origin: 50% 100%;
    transform: scale(0%);
    transition: 0.75s transform ease-out;
    /*filter: grayscale(1) brightness(1.2) sepia(0.2) saturate(10) hue-rotate(300deg);*/
    filter: grayscale(1) brightness(1.1) sepia(0.15) saturate(2);
}

a:hover ~ i {
    transform: scale(100%);
}