body {
    font-family: Arial, sans-serif;
    background-color: #f7f7f7;
}

#calculator {
    background-color: #fff;
    padding: 20px;
    border-radius: 5px;
    max-width: 400px;
    margin: 50px auto;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

#calculator label {
    display: inline-block;
    width: 200px;
    margin-bottom: 10px;
}

#calculator input,
#calculator select {
    width: 150px;
    padding: 5px;
}

#calculator button {
    padding: 10px 20px;
    font-size: 16px;
}

#calculator h2 {
    margin-top: 30px;
}

#calculator p {
    font-size: 18px;
}