#u-preloader{
    position:fixed;
    inset:0;
    display:flex;
    justify-content:center;
    align-items:center;
    background:#FFFEF1;
    z-index:999999;
    overflow:visible; /* важно */
}

.u-preloader__logo{
    width:min(620px,80vw);
    height:auto;
    display:block;
    overflow:visible;
}