Reduce built library size

package.json

@@ -105,6 +105,7 @@
     "node-fetch": "^2.6.7",
     "npm-run-all": "^4.1.5",
     "prettier": "^3.3.3",
+    "rollup-plugin-bundle-stats": "^4.17.0",
     "selenium-webdriver": "^4.26.0",
     "stylelint": "^16.10.0",
     "stylelint-config-standard": "^36.0.1",

src/@types/css-tree.d.ts

@@ -0,0 +1,21 @@
+declare module 'css-tree/walker' {
+  import { walk } from 'css-tree';
+
+  export default walk;
+}
+
+declare module 'css-tree/utils' {
+  export { clone, List } from 'css-tree';
+}
+
+declare module 'css-tree/generator' {
+  import { generate } from 'css-tree';
+
+  export default generate;
+}
+
+declare module 'css-tree/parser' {
+  import { parse } from 'css-tree';
+
+  export default parse;
+}