修改登录和基础功能样式，目前已经支持钉钉登录和自定义登录注册

models.py

@@ -1,18 +1,33 @@
 from datetime import datetime
 from flask_sqlalchemy import SQLAlchemy
 from flask_login import UserMixin
+from werkzeug.security import generate_password_hash, check_password_hash
+import pytz
 
 db = SQLAlchemy()
 
+def now_shanghai():
+    """返回上海时区（UTC+8）的当前时间"""
+    return datetime.now(pytz.timezone('Asia/Shanghai'))
+
 class User(UserMixin, db.Model):
     id = db.Column(db.Integer, primary_key=True)
     username = db.Column(db.String(80), unique=True, nullable=False)
+    password_hash = db.Column(db.String(200))
     role = db.Column(db.String(20), nullable=False, default='user')
     contact = db.Column(db.String(100))
-    dingtalk_userid = db.Column(db.String(100), unique=True, nullable=False)
+    dingtalk_userid = db.Column(db.String(100), unique=True)
     dingtalk_name = db.Column(db.String(100))
     dingtalk_dept = db.Column(db.String(200))
-    created_at = db.Column(db.DateTime, default=datetime.utcnow)
+    created_at = db.Column(db.DateTime, default=now_shanghai)
+    
+    def set_password(self, password):
+        self.password_hash = generate_password_hash(password)
+    
+    def check_password(self, password):
+        if not self.password_hash:
+            return False
+        return check_password_hash(self.password_hash, password)
     
     def is_admin(self):
         return self.role == 'admin'
@@ -27,8 +42,8 @@ class Demand(db.Model):
     answer = db.Column(db.Text)
     answered_at = db.Column(db.DateTime)
     user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
-    created_at = db.Column(db.DateTime, default=datetime.utcnow)
-    updated_at = db.Column(db.DateTime, default=datetime.utcnow)
+    created_at = db.Column(db.DateTime, default=now_shanghai)
+    updated_at = db.Column(db.DateTime, default=now_shanghai)
     
     user = db.relationship('User', backref=db.backref('demands', lazy=True))