diff --git a/examples/nextjs/pages/my.md b/examples/nextjs/pages/my.md
index d71c32e4..8450e8bd 100644
--- a/examples/nextjs/pages/my.md
+++ b/examples/nextjs/pages/my.md
@@ -2,7 +2,7 @@
 
 Lorem ipsum dolor sit amet.
 
-```python hello.py
+```python hello.py mark=1[22:30]
 print("Rendered with Code Hike")
 ```
 
diff --git a/packages/mdx/package.json b/packages/mdx/package.json
index b5e871aa..acc0c34a 100644
--- a/packages/mdx/package.json
+++ b/packages/mdx/package.json
@@ -5,16 +5,16 @@
     "dist"
   ],
   "main": "./dist/index.cjs.js",
-  "module": "./dist/index.esm.js",
+  "module": "./dist/index.esm.mjs",
   "types": "./dist/index.d.ts",
   "exports": {
     ".": {
-      "import": "./dist/index.esm.js",
+      "import": "./dist/index.esm.mjs",
       "require": "./dist/index.cjs.js",
       "style": "./dist/index.css"
     },
     "./components": {
-      "import": "./dist/components.esm.js",
+      "import": "./dist/components.esm.mjs",
       "require": "./dist/components.cjs.js",
       "default": "./dist/components.cjs.js"
     },
@@ -23,13 +23,13 @@
     "./styles.css": "./dist/index.css",
     "./dist/index.css": "./dist/index.css",
     "./dist/components.cjs.js": {
-      "import": "./dist/components.esm.js",
+      "import": "./dist/components.esm.mjs",
       "require": "./dist/components.cjs.js",
       "default": "./dist/components.cjs.js"
     }
   },
   "browser": {
-    "./dist/index.esm.js": "./dist/index.browser.mjs"
+    "./dist/index.esm.mjs": "./dist/index.browser.mjs"
   },
   "scripts": {
     "dev": "next",
diff --git a/packages/mdx/rollup.config.js b/packages/mdx/rollup.config.js
index 81d875d0..6a6b6701 100644
--- a/packages/mdx/rollup.config.js
+++ b/packages/mdx/rollup.config.js
@@ -34,7 +34,7 @@ export default function makeConfig(commandOptions) {
           format: "cjs",
         },
         {
-          file: `./dist/index.esm.js`,
+          file: `./dist/index.esm.mjs`,
           format: "es",
         },
       ],
@@ -84,7 +84,7 @@ export default function makeConfig(commandOptions) {
           format: "cjs",
         },
         {
-          file: `./dist/components.esm.js`,
+          file: `./dist/components.esm.mjs`,
           format: "es",
         },
       ],