.test {
    background: linear-gradient(-45deg, #7a43b6, #6d56c1, #32535f, #7b67c7);
    background-size: 300% 400%;
    animation: gradient 15s ease infinite;
}

@keyframes gradient {
    0% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
    100% {
        background-position: 0% 50%;
    }
}