Complete 4.3.1: Notification System Redesign - Enhanced toast notification system with variants, queue management, and accessibility improvements

UI_UPDATE.MD

@@ -480,10 +480,19 @@ All utilities follow the established pattern of using CSS custom properties from
 
 ### Sub-task 4.3: Enhanced User Feedback Systems
 
-#### 4.3.1: Notification Redesign
-- [ ] Redesign toast notification system
-- [ ] Implement notification variants
-- [ ] Add notification queue management
+#### 4.3.1: Notification Redesign - COMPLETED 9/29/2025
+- [x] Redesign toast notification system
+- [x] Implement notification variants
+- [x] Add notification queue management
+
+**Notes:** Comprehensive notification system redesign completed with:
+- **Enhanced Notification System**: Replaced simple toast with advanced notification system supporting multiple variants (success, error, warning, info), custom actions, progress bars, and smooth animations
+- **Queue Management**: Implemented intelligent queue system that handles up to 5 simultaneous notifications with automatic stacking and dismissal
+- **Variants and Styling**: Four notification variants with distinct colors, icons, and animations (.notification--success, .notification--error, .notification--warning, .notification--info)
+- **Advanced Features**: Hover-to-pause, keyboard navigation (Escape key), ARIA accessibility, progress indicators for auto-dismissing notifications, and smooth slide-in/out animations
+- **Legacy Support**: Maintains backward compatibility with existing showToast() calls while redirecting to the new system
+- **Mobile Responsive**: Full responsive design with mobile-specific positioning and touch-friendly interactions
+- **Api Integration**: New Notifications API (show(), success(), error(), warning(), info()) with configuration options
 
 #### 4.3.2: Loading States
 - [ ] Implement loading indicators