fix: resolve Tailwind CSS v4 configuration and PostCSS plugin issues

Author: tanzilahmed0

frontend/postcss.config.mjs

@@ -1,6 +1,6 @@
 const config = {
   plugins: {
-    tailwindcss: {},
+    '@tailwindcss/postcss': {},
     autoprefixer: {},
   },
 };

frontend/src/app/globals.css

@@ -1,6 +1,4 @@
-@tailwind base;
-@tailwind components;
-@tailwind utilities;
+@import "tailwindcss";
 
 /* Example: Custom global styles */
 body {

frontend/tailwind.config.js

@@ -5,4 +5,8 @@ module.exports = {
     './src/components/**/*.{js,ts,jsx,tsx}',
     './src/lib/**/*.{js,ts,jsx,tsx}',
   ],
+  theme: {
+    extend: {},
+  },
+  plugins: [],
 };