diff --git a/public/academy-video/brew-physics-poster.jpg b/public/academy-video/brew-physics-poster.jpg
new file mode 100644
index 0000000..4a94824
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diff --git a/public/academy-video/brew-physics.mp4 b/public/academy-video/brew-physics.mp4
new file mode 100644
index 0000000..cd4206a
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diff --git a/public/academy-video/roast-physics-poster.jpg b/public/academy-video/roast-physics-poster.jpg
new file mode 100644
index 0000000..bd02a20
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diff --git a/public/academy-video/roast-physics.mp4 b/public/academy-video/roast-physics.mp4
new file mode 100644
index 0000000..078446d
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diff --git a/public/academy.html b/public/academy.html
index da46bc4..c6b3fc9 100644
--- a/public/academy.html
+++ b/public/academy.html
@@ -64,6 +64,48 @@
         <main class="page-content">
           <div id="academy-menu"></div>
 
+          <section class="panel-card" id="academy-films">
+            <div class="panel-head">
+              <h2>Films — the physics in motion</h2>
+            </div>
+            <div class="panel-body">
+              <p class="muted" style="margin-top: 0">
+                Two short macro films of what the lessons teach — every shot
+                generated on the local roaster's GPU.
+              </p>
+              <div class="academy-films-grid">
+                <figure class="academy-film">
+                  <video
+                    src="/academy-video/roast-physics.mp4?v=__ASSET_VERSION__"
+                    poster="/academy-video/roast-physics-poster.jpg?v=__ASSET_VERSION__"
+                    controls
+                    muted
+                    loop
+                    playsinline
+                    preload="metadata"
+                  ></video>
+                  <figcaption>
+                    The roast — charge · drying · Maillard · first crack · drop
+                  </figcaption>
+                </figure>
+                <figure class="academy-film">
+                  <video
+                    src="/academy-video/brew-physics.mp4?v=__ASSET_VERSION__"
+                    poster="/academy-video/brew-physics-poster.jpg?v=__ASSET_VERSION__"
+                    controls
+                    muted
+                    loop
+                    playsinline
+                    preload="metadata"
+                  ></video>
+                  <figcaption>
+                    The brew — grind · bloom · immersion · espresso
+                  </figcaption>
+                </figure>
+              </div>
+            </div>
+          </section>
+
           <section class="panel-card hidden" id="academy-player">
             <div class="panel-head">
               <div>
diff --git a/public/app.css b/public/app.css
index c3184a2..52b7820 100644
--- a/public/app.css
+++ b/public/app.css
@@ -3190,6 +3190,28 @@ select.f {
 	border-color: var(--ember);
 }
 
+.academy-films-grid {
+	display: grid;
+	grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
+	gap: 16px;
+}
+.academy-film {
+	margin: 0;
+}
+.academy-film video {
+	display: block;
+	width: 100%;
+	border-radius: var(--radius-lg);
+	border: 1px solid var(--line);
+	background: #1b1614;
+}
+.academy-film figcaption {
+	margin-top: 8px;
+	font-size: 12.5px;
+	color: var(--ink-2);
+	text-align: center;
+}
+
 /* Scene animations — restarted per slide because the SVG is rebuilt. */
 @keyframes ac-draw-kf { from { stroke-dashoffset: 900; } to { stroke-dashoffset: 0; } }
 .ac-draw { stroke-dasharray: 900; animation: ac-draw-kf 2.6s ease-out forwards; }
diff --git a/public/js/academy.js b/public/js/academy.js
index dc0928e..4553320 100644
--- a/public/js/academy.js
+++ b/public/js/academy.js
@@ -97,6 +97,9 @@ function renderMenu() {
 function openLesson(track, lesson, index) {
 	current = { track, lesson, index };
 	$("academy-menu").classList.add("hidden");
+	$("academy-films")?.classList.add("hidden");
+	// Pause any playing film so it doesn't run (and download) behind the lesson.
+	for (const video of document.querySelectorAll("#academy-films video")) video.pause();
 	$("academy-player").classList.remove("hidden");
 	renderSlide();
 }
@@ -106,6 +109,7 @@ function closeLesson() {
 	current = null;
 	$("academy-player").classList.add("hidden");
 	$("academy-menu").classList.remove("hidden");
+	$("academy-films")?.classList.remove("hidden");
 	renderMenu(); // reflect fresh progress
 }
 
diff --git a/public/sw.js b/public/sw.js
index 53bed2b..bde5386 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -64,7 +64,11 @@ self.addEventListener("fetch", (event) => {
 	if (
 		request.method !== "GET" ||
 		url.origin !== self.location.origin ||
-		url.pathname.startsWith("/api/")
+		url.pathname.startsWith("/api/") ||
+		// Media streams use Range requests (206 responses the Cache API rejects) and are far
+		// too large to belong in the static cache — let the browser handle them natively.
+		url.pathname.startsWith("/academy-video/") ||
+		url.pathname.startsWith("/academy-audio/")
 	)
 		return;
 
@@ -86,10 +90,12 @@ self.addEventListener("fetch", (event) => {
 	event.respondWith(
 		fetch(request)
 			.then((response) => {
-				if (response.ok)
+				// Only full 200 responses: cache.put() throws on 206 partials.
+				if (response.status === 200)
 					caches
 						.open(CACHE_NAME)
-						.then((cache) => cache.put(request, response.clone()));
+						.then((cache) => cache.put(request, response.clone()))
+						.catch(() => {});
 				return response;
 			})
 			.catch(() => caches.match(request)),