Use PostCSS

package.json

@@ -30,8 +30,15 @@
     "@types/animejs": "^3.1.4",
     "@typescript-eslint/eslint-plugin": "^5.29.0",
     "@typescript-eslint/parser": "^5.29.0",
+    "browserslist": "^4.21.0",
+    "cssnano": "^5.1.12",
     "eslint": "^8.18.0",
     "eslint-plugin-svelte3": "^4.0.0",
+    "postcss": "^8.4.14",
+    "postcss-focus-visible": "^6.0.4",
+    "postcss-normalize": "^10.0.1",
+    "postcss-preset-env": "^7.7.1",
+    "postcss-sort-media-queries": "^4.2.1",
     "sass": "^1.52.3",
     "svelte": "^3.48.0",
     "svelte-check": "^2.7.2",