diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index dae0c42..9ce1f4f 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -39,6 +39,9 @@ jobs:
         run: npm install
       - name: Build
         run: npm run build
+      - name: Copy index.html to 404.html
+        # see https://stackoverflow.com/a/76148302
+        run: cp ./dist/index.html ./dist/404.html
       - name: Setup Pages
         uses: actions/configure-pages@v3
       - name: Upload artifact