diff --git a/src/admin/components/odin/OdinChat.tsx b/src/admin/components/odin/OdinChat.tsx
index 8950490..1850d59 100644
--- a/src/admin/components/odin/OdinChat.tsx
+++ b/src/admin/components/odin/OdinChat.tsx
@@ -437,8 +437,13 @@ export default function OdinChat() {
         // page never scrolls and the chat's message list scrolls internally.
         // Desktop: svh === vh.
         // Mobile is immersive (AppShell hides its header and main padding on
-        // /odin): the chat owns the whole viewport, full-bleed.
-        height: { xs: "100svh", md: "calc(100svh - 100px)" },
+        // /odin): the chat owns the whole viewport, full-bleed. --app-height
+        // is AppShell's live window.innerHeight measurement — standalone-PWA
+        // viewports misreport svh/dvh (MIUI), only the measured value fits.
+        height: {
+          xs: "var(--app-height, 100svh)",
+          md: "calc(100svh - 100px)",
+        },
         display: "flex",
         // Longhand on purpose: a responsive `border` shorthand lands in a
         // media query AFTER borderColor and resets the color to black.
diff --git a/src/admin/ui/AppShell.tsx b/src/admin/ui/AppShell.tsx
index df71825..f1e7f5a 100644
--- a/src/admin/ui/AppShell.tsx
+++ b/src/admin/ui/AppShell.tsx
@@ -28,6 +28,27 @@ export default function AppShell() {
   // button. Desktop keeps the normal shell.
   const immersiveOnMobile = location.pathname === "/odin";
 
+  // Installed-PWA (standalone) viewports lie to CSS units: on MIUI/Android
+  // svh/dvh are computed against a viewport that includes system UI the real
+  // layout viewport doesn't have, leaving scroll room no unit can remove
+  // (and Chrome can serve a stale viewport after minimize/restore). Measure
+  // the truth — window.innerHeight — into --app-height and keep it fresh;
+  // immersive layouts size from it with an svh fallback.
+  useEffect(() => {
+    if (!immersiveOnMobile) return;
+    const root = document.documentElement;
+    const set = () =>
+      root.style.setProperty("--app-height", `${window.innerHeight}px`);
+    set();
+    window.addEventListener("resize", set);
+    window.visualViewport?.addEventListener("resize", set);
+    return () => {
+      window.removeEventListener("resize", set);
+      window.visualViewport?.removeEventListener("resize", set);
+      root.style.removeProperty("--app-height");
+    };
+  }, [immersiveOnMobile]);
+
   const handleLogout = useCallback(() => {
     setLoggingOut(true);
     setMobileOpen(false);
@@ -92,7 +113,7 @@ export default function AppShell() {
             // makes body scroll impossible regardless of dvh interpretation.
             minHeight: immersiveOnMobile ? { xs: 0, md: "100dvh" } : "100dvh",
             ...(immersiveOnMobile && {
-              height: { xs: "100svh", md: "auto" },
+              height: { xs: "var(--app-height, 100svh)", md: "auto" },
               overflow: { xs: "hidden", md: "visible" },
             }),
           }}