diff --git a/packages/pigment-css-unplugin/src/index.ts b/packages/pigment-css-unplugin/src/index.ts
index 6f276a05..6ae7addc 100644
--- a/packages/pigment-css-unplugin/src/index.ts
+++ b/packages/pigment-css-unplugin/src/index.ts
@@ -218,11 +218,11 @@ export const plugin = createUnplugin<PigmentOptions, true>((options) => {
       compiler.options.resolve.plugins = compiler.options.resolve.plugins || [];
       compiler.options.resolve.plugins.push(resolverPlugin);
     },
-    async transform(code, filePath) {
-      const [pathSegment] = filePath.split('?');
+    async transform(code, url) {
+      const [filePath] = url.split('?');
       // Converts path separator as per platform, even on Windows, path segments have `/` instead of the usual `\`,
       // so this function replaces such path separators.
-      const id = path.normalize(pathSegment);
+      const id = path.normalize(filePath);
       const transformServices = {
         options: {
           filename: id,