diff --git a/404.html b/404.html
index 3c4a766..7c6f339 100644
--- a/404.html
+++ b/404.html
@@ -2,13 +2,22 @@
 <html lang="ko">
 <head>
 <meta charset="utf-8">
-<script async src="https://www.googletagmanager.com/gtag/js?id=G-BEBVKYH8HL"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-C5V0X2SGD3"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
-  gtag('config', 'G-BEBVKYH8HL');
+  gtag('config', 'G-C5V0X2SGD3', { page_location: location.href });
+  /* GA has the campaign from page_location; keep shared URLs free of utm_* */
+  (function () {
+    try {
+      var u = new URL(location.href), drop = [];
+      u.searchParams.forEach(function (v, k) { if (k.indexOf("utm_") === 0) drop.push(k); });
+      if (drop.length) { drop.forEach(function (k) { u.searchParams.delete(k); }); history.replaceState(history.state, "", u.pathname + u.search + u.hash); }
+    } catch (e) {}
+  })();
 </script>
+<script src="/assets/js/track.js" defer></script>
 <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
 <title>페이지를 찾을 수 없습니다 | Causal Inference Hub</title>
 <link rel="icon" href="/assets/img/team-mark.png">
diff --git a/article.html b/article.html
index 4627f28..1ca2ac5 100644
--- a/article.html
+++ b/article.html
@@ -2,13 +2,22 @@
 <html lang="ko">
 <head>
 <meta charset="utf-8">
-<script async src="https://www.googletagmanager.com/gtag/js?id=G-BEBVKYH8HL"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-C5V0X2SGD3"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
-  gtag('config', 'G-BEBVKYH8HL');
+  gtag('config', 'G-C5V0X2SGD3', { page_location: location.href });
+  /* GA has the campaign from page_location; keep shared URLs free of utm_* */
+  (function () {
+    try {
+      var u = new URL(location.href), drop = [];
+      u.searchParams.forEach(function (v, k) { if (k.indexOf("utm_") === 0) drop.push(k); });
+      if (drop.length) { drop.forEach(function (k) { u.searchParams.delete(k); }); history.replaceState(history.state, "", u.pathname + u.search + u.hash); }
+    } catch (e) {}
+  })();
 </script>
+<script src="assets/js/track.js" defer></script>
 <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
 <title>읽을거리 | Causal Inference Hub</title>
 <meta name="description" content="가짜연구소 인과추론팀이 쓴 글과 독자를 위한 자료입니다.">
diff --git a/assets/js/hub.js b/assets/js/hub.js
index 88ab80c..059df26 100644
--- a/assets/js/hub.js
+++ b/assets/js/hub.js
@@ -782,6 +782,7 @@
   function openStation(id) {
     const r = state.repos.get(id);
     if (!r) return;
+    if (window.hubTrack) window.hubTrack("station_open", { repo: id, level: r.level || "", from_link: stationFromHash() === id ? "yes" : "no" });
     if (r.kind !== "paid") {
       state.recent = [{ id, t: Date.now() }, ...state.recent.filter((x) => x.id !== id)].slice(0, 6);
       saveRecent(); renderWeek();
diff --git a/assets/js/track.js b/assets/js/track.js
new file mode 100644
index 0000000..ddfc17d
--- /dev/null
+++ b/assets/js/track.js
@@ -0,0 +1,51 @@
+/* Analytics helpers shared by every hub page.
+   - hubTrack(name, params): send a GA4 event when the tag is present.
+   - Links to the team's other sites on this domain (the web book, causal-studio, ...) open in the same tab,
+     carry utm_* so the other site's GA property can see the visit came from the hub, and send a click event. */
+(function () {
+  "use strict";
+  window.hubTrack = function (name, params) {
+    try { if (typeof window.gtag === "function") window.gtag("event", name, params || {}); } catch (e) {}
+  };
+
+  const HUB_PATHS = /^\/(?:$|index\.html$|article\.html$|404\.html$|assets\/|data\/|articles\/)/;
+  const WEBBOOK = "Causal-Inference-with-Python";
+
+  function teamSite(a) {
+    let u;
+    try { u = new URL(a.href, location.href); } catch (e) { return null; }
+    if (u.origin !== location.origin || HUB_PATHS.test(u.pathname)) return null;
+    const site = u.pathname.split("/")[1];
+    return site ? { url: u, site } : null;
+  }
+
+  function placement(a) {
+    const spots = [
+      ["#featured", "featured"], [".partner", "partner"], ["#station-dialog", "station"],
+      ["#shelf, #week, .spot", "curriculum"], [".reader, .prose", "article"], [".site-footer", "footer"], [".banner", "banner"]
+    ];
+    for (const [sel, name] of spots) if (a.closest(sel)) return name;
+    return "other";
+  }
+
+  function decorate(e) {
+    const a = e.target.closest && e.target.closest("a[href]");
+    if (!a) return;
+    const t = teamSite(a);
+    if (!t) return;
+    const where = placement(a);
+    const u = t.url;
+    if (!u.searchParams.has("utm_source")) {
+      u.searchParams.set("utm_source", "hub");
+      u.searchParams.set("utm_medium", "referral");
+      u.searchParams.set("utm_campaign", "crosslink");
+      u.searchParams.set("utm_content", where);
+      a.href = u.toString();
+    }
+    /* team sites are one family: open them in place, unless the reader asked for a new tab */
+    if (e.type === "click" && e.button === 0 && !e.metaKey && !e.ctrlKey && !e.shiftKey && !e.altKey) a.removeAttribute("target");
+    window.hubTrack(t.site === WEBBOOK ? "webbook_click" : "team_site_click", { site: t.site, placement: where, link_url: u.origin + u.pathname });
+  }
+  document.addEventListener("click", decorate, true);
+  document.addEventListener("auxclick", decorate, true);
+})();
diff --git a/index.html b/index.html
index 87c031c..53332aa 100644
--- a/index.html
+++ b/index.html
@@ -2,13 +2,22 @@
 <html lang="ko">
 <head>
 <meta charset="utf-8">
-<script async src="https://www.googletagmanager.com/gtag/js?id=G-BEBVKYH8HL"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-C5V0X2SGD3"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
-  gtag('config', 'G-BEBVKYH8HL');
+  gtag('config', 'G-C5V0X2SGD3', { page_location: location.href });
+  /* GA has the campaign from page_location; keep shared URLs free of utm_* */
+  (function () {
+    try {
+      var u = new URL(location.href), drop = [];
+      u.searchParams.forEach(function (v, k) { if (k.indexOf("utm_") === 0) drop.push(k); });
+      if (drop.length) { drop.forEach(function (k) { u.searchParams.delete(k); }); history.replaceState(history.state, "", u.pathname + u.search + u.hash); }
+    } catch (e) {}
+  })();
 </script>
+<script src="assets/js/track.js" defer></script>
 <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
 <title>Causal Inference Hub | 가짜연구소 인과추론팀</title>
 <meta name="description" content="인과추론에서 AI 시대의 데이터 리터러시까지. 가짜연구소 인과추론팀이 2022년부터 함께 만든 오픈소스와 커리큘럼을 한곳에 모은 허브입니다.">