/* Full-page overlay */
#busyOverlay {
    display: none;              /* hidden by default */
    position: fixed;
    inset: 0;
    background: rgba(255,255,255,0.7);
    z-index: 1050;             /* above everything */
    backdrop-filter: blur(1px);
}
/* Center box */
#busyOverlay .center {
    position: absolute; top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
}
#busyOverlay .msg {
    margin-top: 12px; font-weight: 600;
}
/* Disable pointer events on page when overlay shown */
body.busy {
    pointer-events: none;
}