diff --git a/components/StaffReportView.tsx b/components/StaffReportView.tsx
index 3c610e7..2ff795d 100644
--- a/components/StaffReportView.tsx
+++ b/components/StaffReportView.tsx
@@ -76,22 +76,39 @@ export function StaffReportView({
   // When embedded, post our content height to the parent so the Civi tab's
   // iframe can resize to fit (no nested scrollbars). The receiving script
   // lives in the WebForm-mw Civi extension's tab template.
+  //
+  // The root layout sets `html.h-full` and `body.min-h-full`, which tie
+  // document height to the iframe's viewport height. Combined with the
+  // parent setting `iframe.height = postedHeight + 24` on every message,
+  // that creates an unbounded feedback loop (viewport grows -> measured
+  // height grows -> parent grows the iframe -> repeat). Inside the iframe
+  // we decouple html/body from the viewport, measure `body.scrollHeight`
+  // (the actual content), observe the body, and skip duplicate posts.
   useEffect(() => {
     if (!framed || typeof window === "undefined") return;
     if (window.parent === window) return;
+    const html = document.documentElement;
+    const body = document.body;
+    const prevHtmlHeight = html.style.height;
+    const prevBodyMinHeight = body.style.minHeight;
+    html.style.height = "auto";
+    body.style.minHeight = "0";
+    let lastHeight = -1;
     const post = () => {
-      window.parent.postMessage(
-        { type: "webform-mw-height", height: document.documentElement.scrollHeight },
-        "*",
-      );
+      const h = body.scrollHeight;
+      if (h === lastHeight) return;
+      lastHeight = h;
+      window.parent.postMessage({ type: "webform-mw-height", height: h }, "*");
     };
     post();
     const ro = new ResizeObserver(post);
-    ro.observe(document.documentElement);
+    ro.observe(body);
     window.addEventListener("load", post);
     return () => {
       ro.disconnect();
       window.removeEventListener("load", post);
+      html.style.height = prevHtmlHeight;
+      body.style.minHeight = prevBodyMinHeight;
     };
   }, [framed, load]);