diff --git a/instructors/index.qmd b/instructors/index.qmd
index 73dbf7493c..020f1dca9e 100644
--- a/instructors/index.qmd
+++ b/instructors/index.qmd
@@ -609,3 +609,5 @@ subtitle: "Everything an instructor needs to teach AI Systems — two semesters
   <a href="https://github.com/harvard-edge/cs249r_book/discussions" class="btn-secondary">Community</a>
 </div>
 ```
+
+{{< include ../shared/config/_ecosystem-cards.qmd >}}
diff --git a/kits/index.qmd b/kits/index.qmd
index 842a4500df..25ed389425 100644
--- a/kits/index.qmd
+++ b/kits/index.qmd
@@ -165,37 +165,4 @@ Marcelo has also authored open companion books covering the Nicla Vision, XIAO,
 
 3. **Build & Deploy:** Work through the labs for your chosen platform. Start with [Getting Started](contents/getting-started.qmd) for an overview of available exercises.
 
-## Part of the MLSysBook Ecosystem
-
-::: {.content-visible when-format="html"}
-```{=html}
-<div class="row g-3 mt-3">
-  <div class="col-md-4">
-    <div class="p-3 border rounded h-100 ecosystem-link">
-      <h5><a href="https://mlsysbook.ai">Textbook</a></h5>
-      <p class="small text-muted mb-0">Comprehensive theory and concepts covering the full ML systems stack.</p>
-    </div>
-  </div>
-  <div class="col-md-4">
-    <div class="p-3 border rounded h-100 bg-light ecosystem-current">
-      <h5>Hardware Kits</h5>
-      <p class="small text-muted mb-0">Hands-on embedded deployment. <strong>You are here.</strong></p>
-    </div>
-  </div>
-  <div class="col-md-4">
-    <div class="p-3 border rounded h-100 ecosystem-link">
-      <h5><a href="https://mlsysbook.ai/tinytorch">TinyTorch</a></h5>
-      <p class="small text-muted mb-0">Build your own ML framework from scratch.</p>
-    </div>
-  </div>
-</div>
-```
-:::
-
-::: {.content-visible when-format="pdf"}
-These hardware labs complement the broader ML Systems learning experience:
-
-- **Textbook:** Comprehensive theory and concepts covering the full ML systems stack
-- **Hardware Kits:** Hands-on embedded deployment (you are here)
-- **TinyTorch:** Build your own ML framework from scratch
-:::
+{{< include ../shared/config/_ecosystem-cards.qmd >}}
diff --git a/labs/index.qmd b/labs/index.qmd
index 7f24e63436..448bce0c15 100644
--- a/labs/index.qmd
+++ b/labs/index.qmd
@@ -740,10 +740,6 @@ marimo run vol1/lab_01_ml_intro.py</code></pre>
 </div>
 ```
 
-## Part of the MLSysBook Ecosystem
-
-These labs bridge the gap between **reading** about ML systems (the [textbook](https://mlsysbook.ai)) and **building** them from scratch ([TinyTorch](https://mlsysbook.ai/tinytorch/)). Every computation is powered by the [mlsysim](https://mlsysbook.ai/mlsysim/) physics engine --- the same engine used in the textbook's quantitative examples.
-
-- [Share feedback](https://github.com/harvard-edge/cs249r_book/discussions) | [View source](https://github.com/harvard-edge/cs249r_book)
+{{< include ../shared/config/_ecosystem-cards.qmd >}}
 
 :::
diff --git a/mlsysim/docs/index.qmd b/mlsysim/docs/index.qmd
index 851887fef4..77bb880727 100644
--- a/mlsysim/docs/index.qmd
+++ b/mlsysim/docs/index.qmd
@@ -554,3 +554,5 @@ The slide decks, MLSys·im engine, tutorials, and textbook are all part of the s
 :::
 
 :::
+
+{{< include ../../shared/config/_ecosystem-cards.qmd >}}
diff --git a/shared/config/_ecosystem-cards.qmd b/shared/config/_ecosystem-cards.qmd
new file mode 100644
index 0000000000..4909878d3e
--- /dev/null
+++ b/shared/config/_ecosystem-cards.qmd
@@ -0,0 +1,62 @@
+<!--
+  Shared "Part of the MLSysBook Ecosystem" section.
+  Include on a site's landing page with:  {{< include ../shared/config/_ecosystem-cards.qmd >}}
+
+  One source of truth for the cross-site ecosystem links. Every card is a link;
+  a small script marks the CURRENT site "You are here" by reading that site's own
+  <meta name="release-manifest" content="/<site>/release-manifest.json"> — the same
+  per-site signal the footer version pill uses. So one shared block shows each
+  landing page its own state, with no per-page editing.
+-->
+
+## Part of the MLSysBook Ecosystem
+
+::: {.content-visible when-format="html"}
+```{=html}
+<div class="ecosystem-grid row g-3 mt-3">
+  <div class="col-6 col-md-3"><div class="p-3 border rounded h-100 ecosystem-link" data-site="book"><h5><a href="https://mlsysbook.ai/">Textbook</a></h5><p class="small text-muted mb-0">Comprehensive theory across the full ML systems stack.</p></div></div>
+  <div class="col-6 col-md-3"><div class="p-3 border rounded h-100 ecosystem-link" data-site="slides"><h5><a href="https://mlsysbook.ai/slides/">Lecture Slides</a></h5><p class="small text-muted mb-0">Beamer decks and teaching materials for every chapter.</p></div></div>
+  <div class="col-6 col-md-3"><div class="p-3 border rounded h-100 ecosystem-link" data-site="labs"><h5><a href="https://mlsysbook.ai/labs/">Labs</a></h5><p class="small text-muted mb-0">Interactive Marimo notebooks that measure the book's claims.</p></div></div>
+  <div class="col-6 col-md-3"><div class="p-3 border rounded h-100 ecosystem-link" data-site="kits"><h5><a href="https://mlsysbook.ai/kits/">Hardware Kits</a></h5><p class="small text-muted mb-0">Hands-on embedded ML deployment on real devices.</p></div></div>
+  <div class="col-6 col-md-3"><div class="p-3 border rounded h-100 ecosystem-link" data-site="instructors"><h5><a href="https://mlsysbook.ai/instructors/">Instructor Hub</a></h5><p class="small text-muted mb-0">Course maps, syllabi, and adoption resources for teaching.</p></div></div>
+  <div class="col-6 col-md-3"><div class="p-3 border rounded h-100 ecosystem-link" data-site="tinytorch"><h5><a href="https://mlsysbook.ai/tinytorch/">TinyTorch</a></h5><p class="small text-muted mb-0">Build your own ML framework from scratch, module by module.</p></div></div>
+  <div class="col-6 col-md-3"><div class="p-3 border rounded h-100 ecosystem-link" data-site="mlsysim"><h5><a href="https://mlsysbook.ai/mlsysim/">MLSysIM</a></h5><p class="small text-muted mb-0">The physics engine behind every quantitative figure in the book.</p></div></div>
+</div>
+<style>
+  .ecosystem-grid .ecosystem-link h5 a { text-decoration: none; }
+  .ecosystem-grid .ecosystem-link:hover { box-shadow: 0 2px 8px rgba(0,0,0,0.08); }
+  .ecosystem-grid .ecosystem-current { background: var(--bs-light, #f8f9fa); }
+  .ecosystem-grid .ecosystem-current h5 { font-weight: 600; }
+</style>
+<script>
+  (function () {
+    var grid = document.querySelector('.ecosystem-grid');
+    if (!grid) return;
+    var meta = document.querySelector('meta[name="release-manifest"]');
+    var seg = meta ? (meta.getAttribute('content') || '').split('/').filter(Boolean)[0] : '';
+    if (seg === 'vol1' || seg === 'vol2') seg = 'book';
+    if (!seg) return;
+    var card = grid.querySelector('[data-site="' + seg + '"]');
+    if (!card) return;
+    card.classList.remove('ecosystem-link');
+    card.classList.add('ecosystem-current');
+    var h = card.querySelector('h5');
+    if (h) { h.textContent = h.textContent.trim(); }   // drop the link on the current site
+    var p = card.querySelector('p');
+    if (p) { p.innerHTML += ' <strong>You are here.</strong>'; }
+  })();
+</script>
+```
+:::
+
+::: {.content-visible when-format="pdf"}
+The Machine Learning Systems ecosystem:
+
+- **Textbook** --- comprehensive theory across the full ML systems stack
+- **Lecture Slides** --- Beamer decks and teaching materials for every chapter
+- **Labs** --- interactive Marimo notebooks that measure the book's claims
+- **Hardware Kits** --- hands-on embedded ML deployment on real devices
+- **Instructor Hub** --- course maps, syllabi, and adoption resources
+- **TinyTorch** --- build your own ML framework from scratch
+- **MLSysIM** --- the physics engine behind the book's quantitative figures
+:::
diff --git a/slides/index.qmd b/slides/index.qmd
index ad2112b50b..cf09015598 100644
--- a/slides/index.qmd
+++ b/slides/index.qmd
@@ -394,3 +394,5 @@ toc: true
   <a href="https://github.com/harvard-edge/cs249r_book" class="btn-outline" target="_blank">GitHub</a>
 </div>
 ```
+
+{{< include ../shared/config/_ecosystem-cards.qmd >}}