.cpn-calculator-form {
    max-width: 400px;
    margin: 20px auto;
    padding: 20px;
    border: 2px solid #0073aa;
    border-radius: 8px;
    background: #f9f9f9;
    font-family: Arial, sans-serif;
}

.cpn-calculator-form h3 {
    text-align: center;
    margin-bottom: 15px;
    color: #0073aa;
}

.cpn-calculator-form label {
    display: block;
    margin: 10px 0 5px;
}

.cpn-calculator-form input {
    width: 100%;
    padding: 8px;
    box-sizing: border-box;
}

.cpn-calculator-form button {
    margin-top: 15px;
    width: 100%;
    padding: 10px;
    background: #0073aa;
    color: #fff;
    border: none;
    cursor: pointer;
}

#cpnResult {
    margin-top: 20px;
    text-align: center;
    font-weight: bold;
    color: #2c3e50;
}