diff --git a/.changeset/real-cars-greet.md b/.changeset/real-cars-greet.md
new file mode 100644
index 0000000..e24fb32
--- /dev/null
+++ b/.changeset/real-cars-greet.md
@@ -0,0 +1,5 @@
+---
+"bright": major
+---
+
+Remove CJS support. [ESM only](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c).
diff --git a/lib/package.json b/lib/package.json
index 4029a0b..4de5792 100644
--- a/lib/package.json
+++ b/lib/package.json
@@ -1,8 +1,9 @@
 {
   "name": "bright",
   "version": "0.8.6",
+  "type": "module",
+  "module": "./dist/index.js",
   "main": "./dist/index.js",
-  "module": "./dist/index.mjs",
   "types": "./dist/index.d.ts",
   "repository": "https://github.com/code-hike/bright",
   "homepage": "https://bright.codehike.org",
@@ -12,11 +13,11 @@
     "dist/**"
   ],
   "scripts": {
-    "build": "tsup src/index.tsx --format esm,cjs --dts",
-    "watch": "tsup src/index.tsx --format esm,cjs --watch --dts"
+    "build": "tsup src/index.tsx --format esm --dts",
+    "watch": "tsup src/index.tsx --format esm --watch --dts"
   },
   "dependencies": {
-    "@code-hike/lighter": "^1.0.0",
+    "@code-hike/lighter": "^1.0.2",
     "server-only": "^0.0.1"
   },
   "devDependencies": {
diff --git a/web/app/test/page.tsx b/web/app/test/page.tsx
index 51ae039..a517d3a 100644
--- a/web/app/test/page.tsx
+++ b/web/app/test/page.tsx
@@ -33,4 +33,4 @@ export default function Page() {
   )
 }
 
-export const runtime = "edge"
+// export const runtime = "edge"