diff --git a/next.config.js b/next.config.js
deleted file mode 100644
index 591435d..0000000
--- a/next.config.js
+++ /dev/null
@@ -1,12 +0,0 @@
-const { PHASE_EXPORT, PHASE_PRODUCTION_BUILD } = require("next/constants");
-
-module.exports = (phase, { defaultConfig }) => {
-  if (phase === PHASE_EXPORT || phase === PHASE_PRODUCTION_BUILD) {
-    return {
-      output: "export",
-      basePath: "/vanjs.github.io",
-    };
-  }
-
-  return {};
-};
diff --git a/next.config.mjs b/next.config.mjs
new file mode 100644
index 0000000..684d175
--- /dev/null
+++ b/next.config.mjs
@@ -0,0 +1,19 @@
+// /** @type {import('next').NextConfig} */
+// const nextConfig = {
+//   output: "export",
+//   basePath: "/vanjs.github.io",
+// };
+
+// export default nextConfig;
+
+export default (phase, { defaultConfig }) => {
+  /**
+   * @type {import('next').NextConfig}
+   */
+
+  const nextConfig = {
+    basePath: phase !== "phase-development-server" ? "/vanjs.github.io" : "",
+  };
+
+  return nextConfig;
+};