html, body {
    margin: 0;
    padding: 50px;
    font-family: Arial, Helvetica, sans-serif;
    text-align: center;
}

button {
    background-color: #A9A9A9;
    color: #ffffff;
    padding: 5px 10px;
    font-size: 20px;
    cursor: pointer;
}

button:hover,
button:focus {
    background-color: #000000;
}

#overlay {
    display: none;
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background-color: rgba(0,0,0,0.3);
}

#modal {
    background-color: #ffffff;
    max-width: 600px;
    height: 150px;
    margin: 0 auto;
    padding: 20px;
    position: relative;
    top: 30%;
    text-align: center;
}