fixing small bugs; improving background handling and removing dead code

package.json

@@ -13,18 +13,15 @@
   },
   "dependencies": {
     "@hello-pangea/dnd": "^18.0.1",
-    "@tailwindcss/vite": "^4.1.11",
     "preact": "^10.26.4"
   },
   "devDependencies": {
     "@preact/preset-vite": "^2.10.1",
-    "@tailwindcss/postcss": "^4.1.11",
+    "@tailwindcss/vite": "^4.1.11",
     "@types/node": "^22.14.0",
     "@types/react": "^19.1.8",
     "@types/react-dom": "^19.1.5",
-    "autoprefixer": "^10.4.21",
     "playwright": "1.61.1",
-    "postcss": "^8.5.6",
     "tailwindcss": "^4.1.11",
     "typescript": "~5.7.2",
     "vite": "^6.2.0"