.spotlight {
    animation: spotlight 2s ease-in-out infinite alternate;
}

@keyframes spotlight {
    from {
        -webkit-filter: drop-shadow(15px 20px 30px #29a6d8);
        filter: drop-shadow(15px 20px 30px #29a6d8);
    }
    to {
        -webkit-filter: drop-shadow(-10px 15px 35px #3694b9);
        filter: drop-shadow(-10px, 15px, 35px, #3694b9);
    }
}