body, html {
    margin: 0;
    padding: 0;
    height: 100%;
}
#overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}
#overlay-content {
    background: black;
    color: white;
    padding: 20px;
    text-align: center;
}
#overlay button {
    margin: 10px;
    padding: 10px 20px;
    background: white;
    color: black;
    border: none;
    cursor: pointer;
}