.pp-invoice-form {
    max-width: 420px;
    border: 1px solid #eee;
    padding: 16px;
    border-radius: 6px;
    background: #fff;
}

.pp-invoice-form .pp-field {
    margin-bottom: 12px;
}

.pp-invoice-form label {
    display: block;
    font-size: 13px;
    margin-bottom: 6px;
}

.pp-invoice-form input[type="text"],
.pp-invoice-form input[type="email"],
.pp-invoice-form input[type="number"] {
    width: 100%;
    padding: 8px;
    box-sizing: border-box;
    border: 1px solid #ddd;
    border-radius: 4px;
}

.pp-button {
    padding: 10px 16px;
    border-radius: 4px;
    border: none;
    cursor: pointer;
    background: #0073aa;
    color: #fff;
}

.pp-result { margin-top: 12px; }

.pp-success { background: #ecf8f1; padding: 10px; border-radius: 4px; border: 1px solid #bde6c9; }
.pp-error { background: #fff4f4; padding: 10px; border-radius: 4px; border: 1px solid #f1c0c0; color: #a00; }