Update styling and add new heading font

The styling of multiple components has been updated for consistency and readability. A new heading font has been added to improve visual hierarchy. Changes include updating font sizes, adding a new heading font, and adjusting borders and padding over several components.

apps/web/app/(marketing)/_components/site-navigation-item.tsx

@@ -9,7 +9,7 @@ import { cn, isRouteActive } from '@kit/ui/utils';
 const getClassName = (path: string, currentPathName: string) => {
   const isActive = isRouteActive(path, currentPathName);
 
-  return cn(`text-sm font-medium`, {
+  return cn(`text-[0.9em] font-medium`, {
     'hover:underline': !isActive,
   });
 };