style: refine admin dashboard and project management UI with cohesive color palette and improved readability

- Update background colors and text styles for better contrast and legibility.
- Enhance button styles and hover effects for a more modern look.
- Remove unnecessary scaling effects and adjust border styles for consistency.
- Introduce a cohesive design language across components to improve user experience.

components/PerformanceDashboard.tsx

@@ -75,7 +75,7 @@ export const PerformanceDashboard: React.FC = () => {
           setIsVisible(true);
           trackEvent('dashboard-toggle', { action: 'show' });
         }}
-        className="fixed bottom-4 right-4 bg-blue-600 text-white px-4 py-2 rounded-lg shadow-lg hover:bg-blue-700 transition-colors z-50"
+        className="fixed bottom-4 right-4 bg-white text-stone-700 border border-stone-200 px-4 py-2 rounded-lg shadow-md hover:bg-stone-50 transition-colors z-50"
       >
         📊 Performance
       </button>