diff --git a/.github/workflows/firebase-hosting-merge.yml b/.github/workflows/firebase-hosting-merge.yml
index ff2a0a7..ba24873 100644
--- a/.github/workflows/firebase-hosting-merge.yml
+++ b/.github/workflows/firebase-hosting-merge.yml
@@ -12,6 +12,13 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - run: sh tasker.sh build
+      # Pin Node to avoid the keep-alive socket regression in Node 22.23.0 /
+      # 24.17.0 (nodejs/node#63989), which makes firebase-tools fail channel
+      # deploys with "premature close" -> retried release -> FAILED_PRECONDITION.
+      - name: Pin Node for Firebase deploy
+        uses: actions/setup-node@v4
+        with:
+          node-version: "24.18.0"
       - uses: FirebaseExtended/action-hosting-deploy@v0
         with:
           repoToken: '${{ secrets.GITHUB_TOKEN }}'
diff --git a/.github/workflows/firebase-hosting-pull-request.yml b/.github/workflows/firebase-hosting-pull-request.yml
index 9369ea6..73ca921 100644
--- a/.github/workflows/firebase-hosting-pull-request.yml
+++ b/.github/workflows/firebase-hosting-pull-request.yml
@@ -10,6 +10,13 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - run: sh tasker.sh build
+      # Pin Node to avoid the keep-alive socket regression in Node 22.23.0 /
+      # 24.17.0 (nodejs/node#63989), which makes firebase-tools fail channel
+      # deploys with "premature close" -> retried release -> FAILED_PRECONDITION.
+      - name: Pin Node for Firebase deploy
+        uses: actions/setup-node@v4
+        with:
+          node-version: "24.18.0"
       - uses: FirebaseExtended/action-hosting-deploy@v0
         with:
           repoToken: '${{ secrets.GITHUB_TOKEN }}'
diff --git a/mkdocs.yml b/mkdocs.yml
index a58a58d..1209d86 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -205,5 +205,4 @@ markdown_extensions:
 
 extra_javascript:
   - js/config.js
-  - https://polyfill.io/v3/polyfill.min.js?features=es6
   - https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js