Add theme management and settings functionality

- Introduced `ThemeManager` to handle application themes using `ttkthemes`.
- Added `SettingsWindow` for user preferences including theme selection and UI settings.
- Integrated theme selection into the main application with a menu for quick access.
- Enhanced UI components with custom styles based on the selected theme.
- Implemented tooltips for better user guidance across various UI elements.
- Updated dependencies to include `ttkthemes` for improved visual appeal.

README.md

@@ -1,7 +1,7 @@
 # TheChart
-Advanced medication tracking application for monitoring treatment progress and symptom evolution.
+Modern medication tracking application with advanced UI/UX for monitoring treatment progress and symptom evolution.
 
-## Quick Start
+## 🚀 Quick Start
 ```bash
 # Install dependencies
 make install
@@ -14,12 +14,22 @@ make test
 ```
 
 ## 📚 Documentation
-- **[Features Guide](docs/FEATURES.md)** - Complete feature documentation
-- **[Keyboard Shortcuts](docs/KEYBOARD_SHORTCUTS.md)** - Keyboard shortcuts for efficient navigation
-- **[Export System](docs/EXPORT_SYSTEM.md)** - Data export functionality and formats
+- **[Features Guide](docs/FEATURES.md)** - Complete feature documentation with UI/UX improvements
+- **[Keyboard Shortcuts](docs/KEYBOARD_SHORTCUTS.md)** - Comprehensive keyboard shortcuts for efficiency
+- **[Export System](docs/EXPORT_SYSTEM.md)** - Data export functionality (JSON, XML, PDF)
 - **[Development Guide](docs/DEVELOPMENT.md)** - Testing, development, and architecture
-- **[Changelog](docs/CHANGELOG.md)** - Version history and feature evolution
-- **[Quick Reference](#quick-reference)** - Common commands and shortcuts
+- **[Changelog](docs/CHANGELOG.md)** - Version history and recent UI improvements
+- **[Documentation Index](docs/README.md)** - Complete documentation navigation guide
+
+> 💡 **Quick Start**: New users should start with this README, then explore the [Features Guide](docs/FEATURES.md) for detailed functionality. The [Documentation Index](docs/README.md) provides comprehensive navigation.
+
+## ✨ Recent Major Updates (v1.9.5)
+- **🎨 Modern UI/UX**: Professional themes with ttkthemes integration
+- **⌨️ Keyboard Shortcuts**: Comprehensive shortcut system for all operations
+- **💡 Smart Tooltips**: Context-sensitive help throughout the application
+- **🎭 8 Professional Themes**: Arc, Equilux, Adapta, Yaru, Ubuntu, Plastik, Breeze, Elegance
+- **⚙️ Settings System**: Advanced configuration with theme persistence
+- **📊 Enhanced Tables**: Improved selection highlighting and alternating row colors
 
 ## Table of Contents
 - [Prerequisites](#prerequisites)