Update dependency tailwindcss to v4

Author: renovate[bot]

package.json

@@ -15,7 +15,7 @@
     "@astrojs/tailwind": "^5.1.5",
     "astro": "^5.16.6",
     "sass": "^1.97.1",
-    "tailwindcss": "^3.4.17"
+    "tailwindcss": "^4.0.0"
   },
   "devDependencies": {
     "prettier": "^3.7.4",