body {
    font-family: sans-serif;
    text-align: center;
    padding-top: 50px;
    background-color: #e0f7fa;
}
button {
    padding: 15px 30px;
    font-size: 20px;
    margin: 10px;
    cursor: pointer;
}
#clickBtn:disabled {
    background-color: grey;
}