body {
    font-family: sans-serif;
    text-align: center;
    padding-top: 50px;
    background-color: #f4f4f4;
}

#display {
    font-size: 48px;
    font-weight: bold;
    color: #333;
}

button {
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
    background-color: #007BFF;
    color: white;
    border: none;
    border-radius: 5px;
}