#cert-popup-overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.5);
    z-index: 9998;
}
#cert-popup {
    position: fixed;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    background: #fff;
    padding: 30px 20px 20px 20px;
    border-radius: 8px;
    box-shadow: 0 2px 20px rgba(0,0,0,0.2);
    z-index: 9999;
    min-width: 300px;
    max-width: 90vw;
}
#cert-popup h3 {
    margin-top: 0;
}
#cert-popup input[type="text"] {
    font-size: 1.1em;
    padding: 6px;
    margin-bottom: 10px;
}
#cert-popup button {
    margin-right: 10px;
}