body {
    font-family: Arial, sans-serif;
    margin: 20px;
}

.calculator {
    max-width: 400px;
    margin: 0 auto;
    padding: 20px;
    border: 1px solid #ddd;
    border-radius: 8px;
}

.input-group {
    margin-bottom: 15px;
}

label {
    display: block;
    margin-bottom: 5px;
}

button {
    display: block;
    width: 100%;
    padding: 10px;
    background-color: #007bff;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

button:hover {
    background-color: #0056b3;
}