body {
}

.btn {
    /* reset */
    -webkit-appearance: none;
    border: 0;
    outline: 0;
    /* styles */
    position: relative;
    background: linear-gradient(to right, #D6BDDD,#B7B4DB,#ABCADA,#B8D8BC,#D8D8BA,#DDBDC0);
    text-transform: uppercase;
    border-radius:100px;
    padding:10px;
    margin:10px;
    transition: .3s;
    animation: bruh 16s linear infinite;
}

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

    50% {
        background-position: 100% 50%;
    }

    100% {
        background-position: 0 50%;
    }
}