#pdf-popup-overlay {
    position: fixed; top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.5); z-index: 9998;
}
#pdf-popup {
    position: fixed; top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    background: white; padding: 2em;
    z-index: 9999; max-width: 600px;
    border-radius: 8px; box-shadow: 0 0 20px rgba(0,0,0,0.3);
}
#pdf-popup .popup-content { margin-bottom: 1em; }