GH-11: Fixes: Cannot find module 'postcss' (GH-12)

Author: ArtyomVancyan

package.json

@@ -29,7 +29,9 @@
     "identity-obj-proxy": "^3.0.0",
     "jest": "^29.4.3",
     "jest-environment-jsdom": "^29.4.3",
+    "postcss": "^8.4.21",
     "react": "^18.2.0",
+    "react-dom": "^18.2.0",
     "rollup": "3.17.2",
     "rollup-plugin-dts": "^5.2.0",
     "rollup-plugin-less": "^1.1.3",