Enhance styling with updated Tailwind config and CSS

- Extend Tailwind config with experimenta brand colors
- Improve CSS base styles and component formatting
- Update index page with refined typography

tailwind.config.ts

@@ -90,6 +90,17 @@ export default {
         },
       },
 
+      // Font Family
+      fontFamily: {
+        sans: [
+          'Roboto',
+          'system-ui',
+          '-apple-system',
+          'BlinkMacSystemFont',
+          'sans-serif',
+        ],
+      },
+
       // Font Sizes (Mobile-First with responsive variants)
       fontSize: {
         // H1