diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index fe9609c..5b9bbbf 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -55,6 +55,21 @@ jobs:
           mkdir _site
           cp -r index.html article.html game.html lab.html 404.html .nojekyll assets data articles builders badges _site/
 
+      # Browsers keep scripts and styles for up to ten minutes; a version on their URLs makes each deploy load
+      # its own files instead of new HTML running last deploy's scripts.
+      - name: Version script and style URLs
+        run: |
+          python3 - "${GITHUB_SHA::8}" <<'PY'
+          import pathlib, re, sys
+          v = sys.argv[1]
+          pat = re.compile(r'((?:src|href)="(?:\.\./|/)?assets/(?:js|css)/[\w.-]+\.(?:js|css))"')
+          for p in pathlib.Path("_site").rglob("*.html"):
+              t = p.read_text(encoding="utf-8")
+              n = pat.sub(lambda m: f'{m.group(1)}?v={v}"', t)
+              if n != t:
+                  p.write_text(n, encoding="utf-8")
+          PY
+
       - name: Publish to gh-pages
         uses: peaceiris/actions-gh-pages@84c30a85c19949d7eee79c4ff27748b70285e453 # v4
         with:
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 20c4d7b..2dd0e8e 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -89,6 +89,10 @@ python3 scripts/builder_cards.py
 
 `assets/js/track.js`의 `hubTrack(이름, 파라미터)`가 GA4로 이벤트를 보냅니다. GA4가 설치되지 않았으면 아무 일도 하지 않습니다. 이벤트 이름과 파라미터는 PM 문서의 이벤트 사전을 따르고, 새 이벤트를 넣을 때는 사전에도 같이 적습니다. HTML에서는 `data-event="click_join" data-event-params='{"target":"template","source":"builder_page"}'`처럼 속성만으로도 보낼 수 있습니다. 로컬에서 확인하려면 콘솔에서 `window.HUB_DEBUG = true`를 켭니다.
 
+## 배포
+
+`main`에 머지되면 Deploy site 워크플로가 사이트를 만들어 `gh-pages` 브랜치에 올리고, GitHub Pages가 그 브랜치를 공개합니다. **`gh-pages`는 지우지 마세요.** 지우면 Pages 설정이 꺼지고 사이트 전체가 404가 됩니다. 머지된 브랜치를 한꺼번에 지울 때도 `gh-pages`와 `main`은 남겨 두세요.
+
 ## 로컬에서 보기
 
 ```bash
diff --git a/assets/js/ga.js b/assets/js/ga.js
index b296bf3..21cffcf 100644
--- a/assets/js/ga.js
+++ b/assets/js/ga.js
@@ -2,10 +2,9 @@
    counted. Incoming utm_* (from shared links or other team sites) reach GA through page_location
    and are then removed from the address bar so the URL people copy stays clean. */
 (() => {
-  /* ID is the hub's GA4 stream. Google serves no tag script for that ID on its own (gtag/js?id=ID is a 404);
-     the stream's Google tag is TAG, so the script loads from TAG and only ID is configured, which keeps the
-     hub's events in the hub's property. */
-  const ID = "G-C5V0X2SGD3";
+  /* The hub's GA4 stream (measurement ID G-C5V0X2SGD3) is reached through its Google tag, TAG: Google serves
+     the script only for TAG (gtag/js?id=G-C5V0X2SGD3 is a 404), and a page only sends when TAG itself is
+     configured. GA's own install guide for the stream gives this snippet; hits land in the hub property. */
   const TAG = "G-BEBVKYH8HL";
   if (location.hostname === "causalinferencelab.github.io") {
     const s = document.createElement("script");
@@ -15,7 +14,7 @@
     window.dataLayer = window.dataLayer || [];
     window.gtag = function gtag() { window.dataLayer.push(arguments); };
     window.gtag("js", new Date());
-    window.gtag("config", ID, { page_location: location.href, allow_google_signals: false, allow_ad_personalization_signals: false });
+    window.gtag("config", TAG, { page_location: location.href, allow_google_signals: false, allow_ad_personalization_signals: false });
   }
   try {
     const u = new URL(location.href);
diff --git a/scripts/update_stats.py b/scripts/update_stats.py
index 8f88fe7..74169e2 100644
--- a/scripts/update_stats.py
+++ b/scripts/update_stats.py
@@ -6,6 +6,7 @@
 import json
 import os
 import sys
+import urllib.error
 import urllib.parse
 import urllib.request
 from collections import Counter
@@ -90,4 +91,8 @@ def main(out_path):
 
 
 if __name__ == "__main__":
-    main(sys.argv[1] if len(sys.argv) > 1 else "data/stats.json")
+    # A refused or failed GitHub call keeps last week's stats rather than stopping the deploy.
+    try:
+        main(sys.argv[1] if len(sys.argv) > 1 else "data/stats.json")
+    except (urllib.error.HTTPError, urllib.error.URLError) as e:
+        print(f"stats not refreshed, kept as is: {e}", file=sys.stderr)