build: add postcss

web/package.json

@@ -20,16 +20,22 @@
   "devDependencies": {
     "@types/bootstrap": "5.1.2",
     "@types/leaflet.markercluster": "1.4.5",
+    "autoprefixer": "10.3.3",
     "clean-webpack-plugin": "4.0.0",
     "css-loader": "6.2.0",
     "css-minimizer-webpack-plugin": "3.0.2",
     "leaflet.markercluster": "1.5.1",
     "mini-css-extract-plugin": "2.2.2",
+    "postcss": "8.3.6",
+    "postcss-loader": "6.1.1",
     "sass": "1.39.0",
     "sass-loader": "12.1.0",
     "ts-loader": "9.2.5",
     "typescript": "4.4.2",
     "webpack": "5.51.1",
     "webpack-cli": "4.8.0"
-  }
+  },
+  "browserslist": [
+    "defaults"
+  ]
 }