diff --git a/types.go b/types.go
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+package intelligence_finance
+
+// ============================================================
+// General API Response
+// ============================================================
+
+// APIResponse is the general response wrapper returned by the platform APIs.
+type APIResponse struct {
+	Code int                    `json:"code"`
+	Msg  string                 `json:"msg,omitempty"`
+	Data map[string]interface{} `json:"data,omitempty"`
+}
+
+// ============================================================
+// Interface 1: 订单开票接口 (Invoice Create)
+// ============================================================
+
+// InvoiceCreateRequest is the request for creating an invoice order.
+type InvoiceCreateRequest struct {
+	CompanyCode    string               `json:"companyCode,omitempty"`
+	OrderID        string               `json:"orderId"`
+	InvoiceType    int                  `json:"invoiceType"`
+	Products       []InvoiceProduct     `json:"products"`
+	Remark         string               `json:"remark,omitempty"`
+	Purchaser      string               `json:"purchaser"`
+	TaxNum         string               `json:"taxnum,omitempty"`
+	PurchaserAddr  string               `json:"purchaserAddress,omitempty"`
+	PurchaserTel   string               `json:"purchaserTel,omitempty"`
+	BankName       string               `json:"bankName,omitempty"`
+	BankAccount    string               `json:"bankAccount,omitempty"`
+	Phone          string               `json:"phone,omitempty"`
+	Email          string               `json:"email,omitempty"`
+	ApplyPerson    string               `json:"applyPerson,omitempty"`
+	Payee          string               `json:"payee,omitempty"`
+	Reviewer       string               `json:"reviewer,omitempty"`
+	InvoiceRemark  string               `json:"invoiceRemark,omitempty"`
+	NaturalPerson  string               `json:"naturalPerson,omitempty"`
+	AdditionInfo   string               `json:"additionInfo,omitempty"`
+}
+
+// InvoiceProduct represents a single product/service line item in an invoice.
+type InvoiceProduct struct {
+	ProductName      string  `json:"productName"`
+	RevenueCode      string  `json:"revenueCode"`
+	AmountIncludeTax float64 `json:"amountIncludeTax"`
+	Specs            string  `json:"specs,omitempty"`
+	Unit             string  `json:"unit,omitempty"`
+	Quantity         float64 `json:"quantity"`
+	Discount         float64 `json:"discount,omitempty"`
+	TaxSign          int     `json:"taxSign,omitempty"`
+	TaxRate          float64 `json:"taxRate,omitempty"`
+}
+
+// InvoiceCreateResponse is the response for creating an invoice order.
+type InvoiceCreateResponse struct {
+	Status   int              `json:"status"`
+	ErrorMsg string           `json:"errorMsg,omitempty"`
+	DataList []InvoiceData    `json:"dataList"`
+}
+
+// InvoiceData contains detailed information about a single invoice.
+type InvoiceData struct {
+	DeviceCode         string           `json:"deviceCode"`
+	Drawer             string           `json:"drawer"`
+	Email              string           `json:"email"`
+	InvoiceType        string           `json:"invoiceType"`
+	IssueType          string           `json:"issueType"`
+	ListFlag           string           `json:"listFlag"`
+	Mobile             string           `json:"mobile"`
+	OriginalInvCode    string           `json:"originalInvCode,omitempty"`
+	OriginalInvNo      string           `json:"originalInvNo,omitempty"`
+	AdditionInfo       string           `json:"additionInfo,omitempty"`
+	Payee              string           `json:"payee"`
+	PurchaserAddress   string           `json:"purchaserAddress"`
+	PurchaserBankAcct  string           `json:"purchaserBankAccount"`
+	PurchaserBankName  string           `json:"purchaserBankName"`
+	PurchaserName      string           `json:"purchaserName"`
+	PurchaserTaxNo     string           `json:"purchaserTaxNo"`
+	PurchaserTel       string           `json:"purchaserTel"`
+	NaturalPerson      string           `json:"naturalPerson,omitempty"`
+	Remark             string           `json:"remark"`
+	Reviewer           string           `json:"reviewer"`
+	SellerAddress      string           `json:"sellerAddress,omitempty"`
+	SellerBankAcct     string           `json:"sellerBankAccount"`
+	SellerBankName     string           `json:"sellerBankName"`
+	SellerName         string           `json:"sellerName"`
+	CheckCode          string           `json:"checkCode"`
+	CipherText         string           `json:"cipherText"`
+	DrewDate           string           `json:"drewDate,omitempty"`
+	InvoiceCode        string           `json:"invoiceCode"`
+	InvoiceNo          string           `json:"invoiceNo"`
+	InvoiceStatus      string           `json:"invoiceStatus"`
+	LayoutFileURL      string           `json:"layoutFileUrl,omitempty"`
+	PDFURL             string           `json:"pdfUrl,omitempty"`
+	OFDURL             string           `json:"ofdUrl,omitempty"`
+	XMLURL             string           `json:"xmlUrl,omitempty"`
+	TotalExcludeTax    string           `json:"totalExcludeTax"`
+	TotalIncludeTax    string           `json:"totalIncludeTax"`
+	TotalTaxAmount     string           `json:"totalTaxAmount"`
+	LevyingType        string           `json:"levyingType"`
+	Details            []InvoiceDetail  `json:"details"`
+}
+
+// InvoiceDetail represents a product detail line within an invoice.
+type InvoiceDetail struct {
+	Amount             string `json:"amount,omitempty"`
+	Quantity           string `json:"quantity,omitempty"`
+	DeductionAmount    string `json:"deductionAmount,omitempty"`
+	TaxAmount          string `json:"taxAmount,omitempty"`
+	ItemTitle          string `json:"itemTitle"`
+	TaxCode            string `json:"taxCode"`
+	ItemType           string `json:"itemType"`
+	ItemName           string `json:"itemName"`
+	Specs              string `json:"specs,omitempty"`
+	TaxFreePolicy      string `json:"taxFreePolicy"`
+	PreferentialPolicy string `json:"preferentialPolicy"`
+	TaxRate            string `json:"taxRate"`
+	TaxSign            string `json:"taxSign"`
+	Unit               string `json:"unit,omitempty"`
+	UnitPrice          string `json:"unitPrice,omitempty"`
+}
+
+// ============================================================
+// Interface 2: 开票状态查询 (Invoice Status Query)
+// ============================================================
+
+// InvoiceStatusQueryRequest is the request for querying invoice status.
+type InvoiceStatusQueryRequest struct {
+	OrderID string `json:"orderId"`
+}
+
+// InvoiceStatusQueryResponse is the response for querying invoice status.
+type InvoiceStatusQueryResponse struct {
+	Status  int            `json:"status"`
+	Message string         `json:"message,omitempty"`
+	Data    []InvoiceData  `json:"data"`
+}
+
+// ============================================================
+// Interface 3: 创建付款单据 (Create Payment Order)
+// ============================================================
+
+// CreatePaymentOrderRequest is the request for creating a payment order.
+type CreatePaymentOrderRequest struct {
+	Code                     string              `json:"code"`
+	YidaAppType              string              `json:"yidaAppType,omitempty"`
+	EmpAccountUserID         string              `json:"empAccountUserId,omitempty"`
+	Department               *Department         `json:"department,omitempty"`
+	Usage                    string              `json:"usage,omitempty"`
+	PaymentUserID            string              `json:"paymentUserId,omitempty"`
+	Customer                 *Customer           `json:"customer,omitempty"`
+	PrincipalID              string              `json:"principalId,omitempty"`
+	Remark                   string              `json:"remark,omitempty"`
+	Supplier                 *Supplier           `json:"supplier,omitempty"`
+	Title                    string              `json:"title,omitempty"`
+	Project                  *Project            `json:"project,omitempty"`
+	PaymentUserIDListStr     string              `json:"paymentUserIdListStr,omitempty"`
+	NeedPayment              bool                `json:"needPayment,omitempty"`
+	PaymentDetailListJSONStr string              `json:"paymentDetailListJsonStr,omitempty"`
+	PaymentDetailList        []PaymentDetail     `json:"paymentDetailList,omitempty"`
+	Company                  *Company            `json:"company,omitempty"`
+	Amount                   string              `json:"amount,omitempty"`
+	RecipientAccountInfo     *RecipientAccount   `json:"recipientAccountInfo,omitempty"`
+	EnterpriseAccount        *EnterpriseAccount  `json:"enterpriseAccount,omitempty"`
+	Category                 []Category          `json:"category,omitempty"`
+	UserID                   string              `json:"userId"`
+	OccurDate                int64               `json:"occurDate,omitempty"`
+	Product                  *Product            `json:"product,omitempty"`
+	YidaFormUUID             string              `json:"yidaFormUuid,omitempty"`
+	CanEditPaymentInfo       bool                `json:"canEditPaymentInfo,omitempty"`
+	PaymentUserIDList        []string            `json:"paymentUserIdList,omitempty"`
+	YidaProcInsID            string              `json:"yidaProcInsId,omitempty"`
+	SyncPaymentOrder         bool                `json:"syncPaymentOrder,omitempty"`
+}
+
+// Department represents department information.
+type Department struct {
+	Code string `json:"code,omitempty"`
+	Name string `json:"name"`
+}
+
+// Customer represents customer information.
+type Customer struct {
+	Code string `json:"code,omitempty"`
+	Name string `json:"name"`
+}
+
+// Supplier represents supplier information.
+type Supplier struct {
+	Code string `json:"code,omitempty"`
+	Name string `json:"name"`
+}
+
+// Project represents project information.
+type Project struct {
+	Code string `json:"code,omitempty"`
+	Name string `json:"name"`
+}
+
+// Category represents income/expense category information.
+type Category struct {
+	Code string `json:"code,omitempty"`
+	Name string `json:"name"`
+}
+
+// Product represents product information.
+type Product struct {
+	Code string `json:"code,omitempty"`
+	Name string `json:"name"`
+}
+
+// Company represents enterprise entity information.
+type Company struct {
+	Code string `json:"code,omitempty"`
+	Name string `json:"name"`
+}
+
+// EnterpriseAccount represents enterprise account information.
+type EnterpriseAccount struct {
+	EnterpriseAccountCode string `json:"enterpriseAccountCode,omitempty"`
+	AccountCategory       string `json:"accountCategory"`
+	AccountType           string `json:"accountType,omitempty"`
+	CardNo                string `json:"cardNo,omitempty"`
+	AccountName           string `json:"accountName,omitempty"`
+	OfficialNumber        string `json:"officialNumber,omitempty"`
+	OfficialName          string `json:"officialName,omitempty"`
+	Name                  string `json:"name,omitempty"`
+	Code                  string `json:"code,omitempty"`
+	City                  string `json:"city,omitempty"`
+	Province              string `json:"province,omitempty"`
+}
+
+// RecipientAccount represents recipient account information.
+type RecipientAccount struct {
+	AccountCategory string `json:"accountCategory"`
+	AccountType     string `json:"accountType,omitempty"`
+	CardNo          string `json:"cardNo,omitempty"`
+	AccountName     string `json:"accountName,omitempty"`
+}
+
+// PaymentDetail represents a payment detail line item.
+type PaymentDetail struct {
+	Amount       string       `json:"amount,omitempty"`
+	InvoiceInfo  *InvoiceInfo `json:"invoiceInfo,omitempty"`
+	ProductCode  string       `json:"productCode,omitempty"`
+	ProjectCode  string       `json:"projectCode,omitempty"`
+	Remark       string       `json:"remark,omitempty"`
+	PrincipalID  string       `json:"principalId,omitempty"`
+	Tax          string       `json:"tax,omitempty"`
+}
+
+// InvoiceInfo represents invoice information within a payment detail.
+type InvoiceInfo struct {
+	InvoiceNo   string `json:"invoiceNo,omitempty"`
+	InvoiceCode string `json:"invoiceCode,omitempty"`
+}
+
+// CreatePaymentOrderResponse is the response for creating a payment order.
+type CreatePaymentOrderResponse struct {
+	Code string `json:"code"`
+}
+
+// ============================================================
+// Interface 4: 支付完成通知 (Payment Notification - Callback)
+// ============================================================
+
+// PaymentNotificationData represents the payment notification data sent by the platform.
+type PaymentNotificationData struct {
+	Code                 string               `json:"code"`
+	InstanceID           string               `json:"instanceId"`
+	CorpID               string               `json:"corpId"`
+	PaymentStatus        string               `json:"paymentStatus"`
+	PaymentTime          string               `json:"paymentTime"`
+	UserID               string               `json:"userId"`
+	FailReason           string               `json:"failReason,omitempty"`
+	PayerAccountInfo     *PayerAccountInfo    `json:"payerAccountInfo,omitempty"`
+	PayeeAccountInfo     *PayeeAccountInfo    `json:"payeeAccountInfo,omitempty"`
+	RelatedRowNumberList []string             `json:"relatedRowNumberList,omitempty"`
+	Source               string               `json:"source,omitempty"`
+	Template             string               `json:"template,omitempty"`
+	Amount               string               `json:"amount,omitempty"`
+}
+
+// PayerAccountInfo represents the payer's account information.
+type PayerAccountInfo struct {
+	BankOpenDTO           *BankOpenDTO `json:"bankOpenDTO,omitempty"`
+	EnterpriseAccountCode string      `json:"enterpriseAccountCode,omitempty"`
+	AccountType          string       `json:"accountType,omitempty"`
+}
+
+// PayeeAccountInfo represents the payee's account information.
+type PayeeAccountInfo struct {
+	BankOpenDTO *BankOpenDTO `json:"bankOpenDTO,omitempty"`
+}
+
+// BankOpenDTO represents bank account information.
+type BankOpenDTO struct {
+	BankCode       string `json:"bankCode,omitempty"`
+	BankName       string `json:"bankName,omitempty"`
+	BankBranchCode string `json:"bankBranchCode,omitempty"`
+	BankBranchName string `json:"bankBranchName,omitempty"`
+	AccountName    string `json:"accountName,omitempty"`
+	BankCardNo     string `json:"bankCardNo,omitempty"`
+	Type           string `json:"type,omitempty"`
+}
+
+// PaymentStatus constants.
+const (
+	PaymentStatusSuccess    = "SUCCESS"
+	PaymentStatusFail       = "FAIL"
+	PaymentStatusTerminate  = "TERMINATE"
+	PaymentStatusWaitPay    = "WAIT_PAY"
+	PaymentStatusPaying     = "PAYING"
+	PaymentStatusPartSucc   = "PART_SUCCESS"
+	PaymentStatusRefund     = "REFUND"
+)
+
+// Source constants for payment notifications.
+const (
+	SourceApproval = "approval"
+	SourceOpenAPI  = "openapi"
+)
+
+// AccountType constants.
+const (
+	AccountTypeAlipay           = "ALIPAY"
+	AccountTypeBankCard         = "BANKCARD"
+	AccountTypeCorpBankCard     = "CORP_BANK_CARD"
+	AccountTypePersonalBankCard = "PERSONAL_BANK_CARD"
+)
+
+// ============================================================
+// Interface 5: 支付状态查询 (Payment Status Query)
+// ============================================================
+
+// PaymentStatusQueryRequest is the request for querying payment status.
+type PaymentStatusQueryRequest struct {
+	Code   string `json:"code"`
+	UserID string `json:"userId"`
+}
+
+// PaymentStatusQueryResponse is the response for querying payment status,
+// which has the same structure as PaymentNotificationData.
+type PaymentStatusQueryResponse struct {
+	PaymentNotificationData
+}
+
+// ============================================================
+// Generic Notification (Business Notification)
+// ============================================================
+
+// NotificationRequest represents a generic notification request from the platform.
+type NotificationRequest struct {
+	BizType string `json:"bizType"`
+	BizID   string `json:"bizId"`
+	Data    string `json:"data,omitempty"`
+}
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