Enhance the look and feel of forms and data display for improved UI

Updates the styles of input fields, vendor sections, and filter cards to provide better visual consistency.

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-26c014852236/19d76f99-63e3-4717-987b-4fafe960e234.jpg

client/src/components/NewSaleForm.tsx

@@ -168,7 +168,7 @@ export default function NewSaleForm() {
             {/* Seller Information */}
             <div className="modern-section modern-section-vendor">
               <div className="modern-section-header">
-                <div className="modern-icon-container">
+                <div className="w-10 h-10 bg-purple-500 text-white flex items-center justify-center border-2 border-purple-500 shadow-md">
                   <User className="h-5 w-5" />
                 </div>
                 <span className="truncate">Informations Vendeur</span>