#spin1 {
    font-size: 5rem;
    font-weight: bold;
    color: #fff;
    text-shadow: 
        1px 1px 0px #e63946, 
        2px 2px 0px #f77f00, 
        3px 3px 0px #fcbf49, 
        4px 4px 0px #a8dadc, 
        5px 5px 0px #457b9d;
    transform: rotateY(0deg);
    transform-style: preserve-3d;
    animation: spin-3d 4s infinite linear;
}

@keyframes spin-3d {
    0% {
        transform: rotateY(0deg);
    }
    100% {
        transform: rotateY(360deg);
    }
}