diff --git a/src/Main.java b/src/Main.java
index da267d3..385b8e2 100644
--- a/src/Main.java
+++ b/src/Main.java
@@ -12,7 +12,14 @@ public class Main extends Application {
     private Stage primaryStage;
     private MailSender mailSender = new MailSender("3417398995@qq.com", "zhwytlhmucfxcibe");
     private String generatedCode;
-    private Map<String, String> userDatabase = new HashMap<>(); // 存储邮箱 -> 密码
+
+    // 存储用户信息：邮箱 -> 密码
+    private Map<String, String> userDatabase = new HashMap<>();
+    // 存储用户名 -> 邮箱 映射
+    private Map<String, String> usernameToEmail = new HashMap<>();
+    // 存储邮箱 -> 用户名 映射
+    private Map<String, String> emailToUsername = new HashMap<>();
+
     private Map<String, String> currentUser = new HashMap<>(); // 存储当前登录用户信息
     private List<Question> currentExam = new ArrayList<>();
     private int currentIndex = 0;
@@ -39,26 +46,29 @@ public class Main extends Application {
         Label titleLabel = new Label("数学学习软件 - 登录");
         titleLabel.setStyle("-fx-font-size: 16; -fx-font-weight: bold;");
 
-        TextField emailField = new TextField();
-        emailField.setPromptText("请输入邮箱");
+        TextField loginField = new TextField();
+        loginField.setPromptText("请输入邮箱或用户名");
         PasswordField passwordField = new PasswordField();
         passwordField.setPromptText("请输入密码");
 
         Button loginBtn = new Button("登录");
         Button registerBtn = new Button("前往注册");
         Label infoLabel = new Label();
+        Label tipLabel = new Label("提示：可以使用邮箱或用户名登录");
+        tipLabel.setStyle("-fx-font-size: 10; -fx-text-fill: gray;");
 
         // 登录按钮事件
         loginBtn.setOnAction(e -> {
-            String email = emailField.getText().trim();
+            String loginInput = loginField.getText().trim();
             String password = passwordField.getText();
 
-            if (email.isEmpty() || password.isEmpty()) {
-                infoLabel.setText("请输入邮箱和密码");
+            if (loginInput.isEmpty() || password.isEmpty()) {
+                infoLabel.setText("请输入登录信息和密码");
                 return;
             }
 
-            if (!userDatabase.containsKey(email)) {
+            String email = getEmailFromLoginInput(loginInput);
+            if (email == null) {
                 infoLabel.setText("用户不存在");
                 return;
             }
@@ -70,7 +80,8 @@ public class Main extends Application {
 
             // 登录成功
             currentUser.put("email", email);
-            infoLabel.setText("登录成功！");
+            currentUser.put("username", emailToUsername.get(email));
+            infoLabel.setText("登录成功！欢迎 " + emailToUsername.get(email));
             primaryStage.setScene(buildLevelSelectionScene());
         });
 
@@ -79,10 +90,21 @@ public class Main extends Application {
             primaryStage.setScene(buildRegisterScene());
         });
 
-        root.getChildren().addAll(titleLabel, emailField, passwordField, loginBtn, registerBtn, infoLabel);
+        root.getChildren().addAll(titleLabel, loginField, passwordField, tipLabel, loginBtn, registerBtn, infoLabel);
         return new Scene(root, 400, 300);
     }
 
+    // 根据登录输入获取邮箱
+    private String getEmailFromLoginInput(String loginInput) {
+        // 如果输入包含@，认为是邮箱
+        if (loginInput.contains("@")) {
+            return userDatabase.containsKey(loginInput) ? loginInput : null;
+        } else {
+            // 否则认为是用户名
+            return usernameToEmail.get(loginInput);
+        }
+    }
+
     // 注册界面
     private Scene buildRegisterScene() {
         VBox root = new VBox(10);
@@ -90,6 +112,8 @@ public class Main extends Application {
         Label titleLabel = new Label("用户注册");
         titleLabel.setStyle("-fx-font-size: 16; -fx-font-weight: bold;");
 
+        TextField usernameField = new TextField();
+        usernameField.setPromptText("设置用户名 (4-10位字符)");
         TextField emailField = new TextField();
         emailField.setPromptText("请输入邮箱");
         Button sendCodeBtn = new Button("发送验证码");
@@ -104,7 +128,20 @@ public class Main extends Application {
         Label infoLabel = new Label();
 
         sendCodeBtn.setOnAction(e -> {
+            String username = usernameField.getText().trim();
             String email = emailField.getText().trim();
+
+            // 验证用户名
+            if (!isValidUsername(username)) {
+                infoLabel.setText("用户名必须4-10位，只能包含字母、数字和下划线");
+                return;
+            }
+
+            if (usernameToEmail.containsKey(username)) {
+                infoLabel.setText("用户名已存在");
+                return;
+            }
+
             if (!email.contains("@")) {
                 infoLabel.setText("邮箱格式不正确");
                 return;
@@ -130,11 +167,22 @@ public class Main extends Application {
         });
 
         registerBtn.setOnAction(e -> {
+            String username = usernameField.getText().trim();
             String email = emailField.getText().trim();
             String inputCode = codeField.getText().trim();
             String pw = passwordField.getText();
             String pwConfirm = confirmPasswordField.getText();
 
+            if (!isValidUsername(username)) {
+                infoLabel.setText("用户名必须4-10位，只能包含字母、数字和下划线");
+                return;
+            }
+
+            if (usernameToEmail.containsKey(username)) {
+                infoLabel.setText("用户名已存在");
+                return;
+            }
+
             if (!inputCode.equals(generatedCode)) {
                 infoLabel.setText("验证码错误");
             } else if (!pw.equals(pwConfirm)) {
@@ -144,10 +192,14 @@ public class Main extends Application {
             } else if (userDatabase.containsKey(email)) {
                 infoLabel.setText("邮箱已注册");
             } else {
+                // 注册用户
                 userDatabase.put(email, pw);
-                infoLabel.setText("注册成功！");
+                usernameToEmail.put(username, email);
+                emailToUsername.put(email, username);
+                infoLabel.setText("注册成功！用户名: " + username);
                 // 注册成功后自动登录
                 currentUser.put("email", email);
+                currentUser.put("username", username);
                 primaryStage.setScene(buildLevelSelectionScene());
             }
         });
@@ -156,9 +208,18 @@ public class Main extends Application {
             primaryStage.setScene(buildLoginScene());
         });
 
-        root.getChildren().addAll(titleLabel, emailField, sendCodeBtn, codeField,
+        root.getChildren().addAll(titleLabel, usernameField, emailField, sendCodeBtn, codeField,
                 passwordField, confirmPasswordField, registerBtn, backBtn, infoLabel);
-        return new Scene(root, 400, 400);
+        return new Scene(root, 400, 450);
+    }
+
+    // 用户名验证方法
+    private boolean isValidUsername(String username) {
+        if (username.length() < 4 || username.length() > 10) {
+            return false;
+        }
+        // 只能包含字母、数字、下划线
+        return username.matches("^[a-zA-Z0-9_]+$");
     }
 
     // 密码验证方法
@@ -183,6 +244,12 @@ public class Main extends Application {
     private Scene buildLevelSelectionScene() {
         VBox root = new VBox(15);
         root.setStyle("-fx-padding: 20;");
+
+        // 显示欢迎信息
+        String username = currentUser.get("username");
+        Label welcomeLabel = new Label("欢迎, " + username + "!");
+        welcomeLabel.setStyle("-fx-font-size: 16; -fx-font-weight: bold; -fx-text-fill: #2E8B57;");
+
         Label label = new Label("请选择难度");
         label.setStyle("-fx-font-size: 14; -fx-font-weight: bold;");
 
@@ -214,7 +281,7 @@ public class Main extends Application {
         HBox bottomBox = new HBox(10, changePwdBtn, logoutBtn);
         bottomBox.setStyle("-fx-alignment: center;");
 
-        root.getChildren().addAll(label, buttonBox, bottomBox);
+        root.getChildren().addAll(welcomeLabel, label, buttonBox, bottomBox);
         Scene scene = new Scene(root, 400, 300);
         primaryStage.setScene(scene);
         return scene;
@@ -227,6 +294,9 @@ public class Main extends Application {
         Label titleLabel = new Label("修改密码");
         titleLabel.setStyle("-fx-font-size: 16; -fx-font-weight: bold;");
 
+        Label userLabel = new Label("用户: " + currentUser.get("username"));
+        userLabel.setStyle("-fx-font-size: 12; -fx-text-fill: gray;");
+
         PasswordField oldPwdField = new PasswordField();
         oldPwdField.setPromptText("请输入原密码");
         PasswordField newPwdField = new PasswordField();
@@ -260,9 +330,9 @@ public class Main extends Application {
             primaryStage.setScene(buildLevelSelectionScene());
         });
 
-        root.getChildren().addAll(titleLabel, oldPwdField, newPwdField, confirmPwdField,
+        root.getChildren().addAll(titleLabel, userLabel, oldPwdField, newPwdField, confirmPwdField,
                 confirmBtn, backBtn, infoLabel);
-        return new Scene(root, 400, 300);
+        return new Scene(root, 400, 350);
     }
 
     // 输入题目数量界面
@@ -370,7 +440,6 @@ public class Main extends Application {
     }
 
     // 显示分数
-    // 显示分数（详细版）
     private Scene buildScoreScene() {
         VBox root = new VBox(15);
         root.setStyle("-fx-padding: 30; -fx-alignment: center; -fx-background-color: #f5f5f5;");