docs: 更新README添加新功能说明和暗黑模式截图

- 添加标签管理、预算管理、周期记账功能描述
- 新增暗黑模式截图展示区域
- 更新产品预览截图
- 修复暗黑模式下折线图金额数字不可见的问题

Author: TNT-Likely

README.md

@@ -122,6 +122,19 @@
   <img src="demo/preview/zh/12-import-confirm.png" alt="导入确认" width="200" />
 </div>
 
+### 🌙 暗黑模式
+
+<div align="center">
+  <img src="demo/preview/dark/01-home.png" alt="首页-暗黑" width="200" />
+  <img src="demo/preview/dark/02-chart-analysis.png" alt="图表分析-暗黑" width="200" />
+  <img src="demo/preview/dark/03-discover.png" alt="发现-暗黑" width="200" />
+  <img src="demo/preview/dark/04-profile.png" alt="我的-暗黑" width="200" />
+</div>
+
+<div align="center">
+  <img src="demo/preview/dark/05-ai-chat.png" alt="AI对话-暗黑" width="200" />
+</div>
+
 </details>
 
 ## 🌟 核心特性
@@ -189,8 +202,11 @@
 - **独立账户管理**：支持现金、银行卡、信用卡等多种账户类型，每个账户独立记录余额
 - **账户转账功能**：支持账户间转账记录，自动更新双方账户余额
 - **二级分类系统**：支持父子分类层级，更细致的账单归类（可选择一级或二级分类模式）
+- **标签管理**（New!）：为交易添加自定义标签，支持多标签、颜色标记，灵活归类和筛选
+- **预算管理**（New!）：设置月度总预算和分类预算，实时追踪支出进度，超支提醒
+- **周期记账**（New!）：支持每日/每周/每月/每年自动记账，适合固定收支（房租、工资等）
 - **图表分析**：月度报表、分类排行、趋势分析
-- **数据导入导出**：CSV 格式，兼容主流应用
+- **数据导入导出**：CSV 格式，兼容主流应用；支持配置导入导出（YAML 格式）
 - **桌面小组件**：iOS/Android 桌面小组件，快速查看收支情况
 
 ### 🎨 个性化与国际化

README_EN.md

@@ -114,6 +114,19 @@ A lightweight, open-source, privacy-focused **personal finance management** and
   <img src="demo/preview/en/12-import-confirm.png" alt="Import Confirmation" width="200" />
 </div>
 
+### 🌙 Dark Mode
+
+<div align="center">
+  <img src="demo/preview/dark/01-home.png" alt="Home-Dark" width="200" />
+  <img src="demo/preview/dark/02-chart-analysis.png" alt="Chart Analysis-Dark" width="200" />
+  <img src="demo/preview/dark/03-discover.png" alt="Discover-Dark" width="200" />
+  <img src="demo/preview/dark/04-profile.png" alt="Profile-Dark" width="200" />
+</div>
+
+<div align="center">
+  <img src="demo/preview/dark/05-ai-chat.png" alt="AI Chat-Dark" width="200" />
+</div>
+
 </details>
 
 ## 🌟 Key Features
@@ -181,6 +194,9 @@ A lightweight, open-source, privacy-focused **personal finance management** and
 - **Independent Account Management**: Support for cash, bank cards, credit cards and other account types, each account tracks balance independently
 - **Account Transfer Feature**: Support inter-account transfer records, auto-update balances for both accounts
 - **Hierarchical Category System**: Support parent-child category levels for more detailed transaction classification (choose between flat or hierarchical mode)
+- **Tag Management** (New!): Add custom tags to transactions, support multiple tags, color markers, flexible categorization and filtering
+- **Budget Management** (New!): Set monthly total and category budgets, real-time spending progress tracking, overspend alerts
+- **Recurring Transactions** (New!): Support daily/weekly/monthly/yearly automatic recording, suitable for fixed income/expenses (rent, salary, etc.)
 - **Chart Analysis**: Monthly reports, category rankings, trend analysis
 - **Data Import/Export**: CSV format, compatible with mainstream apps
 - **Home Screen Widgets**: iOS/Android widgets for quick overview of income and expenses