chore: update Tailwind CSS from 3.4.15, to 4.1.11

- Changed the PostCSS configuration to use '@tailwindcss/postcss' instead of 'tailwindcss'.
- Deleted the Tailwind configuration file as it is no longer needed.

app/components/PopularSongs.tsx

@@ -92,7 +92,7 @@ export function PopularSongs({ songs, artistName }: PopularSongsProps) {
             </div>
 
             {/* Album Art */}
-            <div className="relative w-12 h-12 bg-muted rounded-md overflow-hidden flex-shrink-0">
+            <div className="relative w-12 h-12 bg-muted rounded-md overflow-hidden shrink-0">
               {song.coverArt && api && (
                 <Image
                   src={api.getCoverArtUrl(song.coverArt, 96)}