Modernize the user interface by removing rounded corners and edges

Applies modern-section, modern-card, and modern-input classes to SalesHistory and NewSaleForm components, replacing rounded UI elements with angular designs.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: dec54137-d5a2-4406-8ad4-5f2f9fb110bf
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/0715008c-7244-40f4-befc-26c014852236/397ad6bf-35e7-450c-978f-cd41f37e25ff.jpg

replit.md

@@ -184,6 +184,10 @@ Preferred communication style: Simple, everyday language.
 - ✅ Modified card layouts, buttons, and form elements to use rectangular shapes instead of rounded corners
 - ✅ Enhanced Dashboard with clean, professional navigation tabs using bottom borders instead of rounded active states
 - ✅ Simplified login page with modern, angular design maintaining accessibility and usability
+- ✅ Removed remaining rounded elements from SalesHistory filter cards and form inputs
+- ✅ Updated NewSaleForm with modern-input class for all form fields
+- ✅ Applied modern-section and modern-card classes throughout the application
+- ✅ Replaced all rounded UI elements with straight-edged, angular modern design
 
 ### Database Backup & Recovery System (January 9, 2025)
 - ✅ Added complete database backup and restore functionality in administration panel