diff --git a/public/test-host.html b/public/test-host.html
index e8a9e9a..6dc8759 100644
--- a/public/test-host.html
+++ b/public/test-host.html
@@ -23,19 +23,32 @@
         .layout {
             display: grid;
             grid-template-columns: 360px minmax(0, 1fr);
-            min-height: 100vh;
+            height: 100vh;
         }
 
         .panel {
             padding: 24px;
             background: #ffffff;
             border-right: 1px solid #e5e7eb;
+            overflow: auto;
         }
 
         .preview {
-            padding: 24px;
+            width: 500px;
+            height: 800px;
+            overflow: auto;
         }
 
+        .preview-frame {
+            width: 800px;
+            height: 300px;
+            overflow: hidden;
+            border: 1px solid #d1d5db;
+            border-radius: 16px;
+            background: #ffffff;
+        }
+
+
         h1 {
             margin: 0 0 8px;
             font-size: 20px;
@@ -98,14 +111,15 @@
             font: 12px/1.5 ui-monospace, SFMono-Regular, Menlo, monospace;
             white-space: pre-wrap;
             min-height: 160px;
+            max-height: min(360px, calc(100vh - 260px));
+            overflow: auto;
         }
 
         iframe {
+            display: block;
             width: 100%;
-            height: calc(100vh - 48px);
-            border: 1px solid #d1d5db;
-            border-radius: 16px;
-            background: #ffffff;
+            height: 100%;
+            border: 0;
         }
 
         @media (max-width: 960px) {
@@ -118,7 +132,8 @@
                 border-bottom: 1px solid #e5e7eb;
             }
 
-            iframe {
+            .preview-frame {
+                width: 100%;
                 height: 70vh;
             }
         }
@@ -149,23 +164,46 @@
     </aside>
 
     <main class="preview">
-        <iframe id="playx-frame" title="PlayX App" src="/"></iframe>
+            <iframe id="playx-frame" title="PlayX App" src="/"></iframe>
     </main>
 </div>
 
 <script>
     const frame = document.getElementById('playx-frame')
+    const previewFrame = document.getElementById('preview-frame')
     const usernameInput = document.getElementById('username')
     const languageInput = document.getElementById('language')
     const sendButton = document.getElementById('send')
     const reloadButton = document.getElementById('reload')
     const logNode = document.getElementById('log')
     const iframeOrigin = window.location.origin
+    const maxLogEntries = 80
+    const logEntries = []
+    const heightLogDelay = 300
+    let pendingHeightLog = null
+    let heightLogTimer = null
 
     function appendLog(message, data) {
         const stamp = new Date().toLocaleTimeString()
         const payload = data ? ` ${JSON.stringify(data, null, 2)}` : ''
-        logNode.textContent = `[${stamp}] ${message}${payload}\n${logNode.textContent}`
+        logEntries.unshift(`[${stamp}] ${message}${payload}`)
+        logEntries.length = Math.min(logEntries.length, maxLogEntries)
+        logNode.textContent = logEntries.join('\n')
+        logNode.scrollTop = 0
+    }
+
+    function scheduleHeightLog(message) {
+        pendingHeightLog = message
+
+        if (heightLogTimer != null) {
+            window.clearTimeout(heightLogTimer)
+        }
+
+        heightLogTimer = window.setTimeout(() => {
+            appendLog('Received PLAYX_HEIGHT from iframe', pendingHeightLog)
+            pendingHeightLog = null
+            heightLogTimer = null
+        }, heightLogDelay)
     }
 
     function buildPayload() {
@@ -181,11 +219,9 @@
     function sendContext() {
         const message = buildPayload()
         frame.contentWindow?.postMessage(message, iframeOrigin)
-        appendLog('Sent IFRAME_CONTEXT to iframe', message)
     }
 
     frame.addEventListener('load', () => {
-        appendLog('Iframe loaded', {src: frame.getAttribute('src')})
     })
 
     sendButton.addEventListener('click', () => {
@@ -194,23 +230,24 @@
 
     reloadButton.addEventListener('click', () => {
         frame.contentWindow?.location.reload()
-        appendLog('Requested iframe reload')
     })
 
     window.addEventListener('message', (event) => {
         if (event.source === frame.contentWindow && event.data?.type === 'PLAYX_READY') {
-            appendLog('Received PLAYX_READY from iframe', {
-                origin: event.origin,
-                data: event.data,
-            })
             sendContext()
             return
         }
 
-        appendLog('Received postMessage on host page', {
-            origin: event.origin,
-            data: event.data,
-        })
+        if (event.source === frame.contentWindow && event.data?.type === 'PLAYX_HEIGHT') {
+            const height = Number(event.data?.payload?.height)
+
+            if (!Number.isFinite(height) || height <= 0) {
+                return
+            }
+
+            scheduleHeightLog(event.data)
+            return
+        }
     })
 </script>
 </body>
diff --git a/src/features/authGuide.tsx b/src/features/authGuide.tsx
index 4da46c4..4d9e308 100644
--- a/src/features/authGuide.tsx
+++ b/src/features/authGuide.tsx
@@ -10,8 +10,10 @@ import {useUserStore} from '@/store/user.ts'
 import type {HostContextMessage} from '@/types'
 
 const HOST_READY_MESSAGE = 'PLAYX_READY'
+const HOST_HEIGHT_MESSAGE = 'PLAYX_HEIGHT'
 const HOST_READY_INTERVAL = 500
 const HOST_READY_RETRY_LIMIT = 20
+const HOST_HEIGHT_REPORT_INTERVAL = 250
 const TEST_BOOTSTRAP_ENABLED = import.meta.env.VITE_BYPASS_IFRAME_CONTEXT === 'true'
 const TEST_BOOTSTRAP_USERNAME = '+60777777777'
 const TEST_BOOTSTRAP_LANGUAGE = 'zh'
@@ -142,6 +144,97 @@ export function AuthGuide({children}: PropsWithChildren) {
         clearUserInfo()
     }, [authBootstrapQuery.isError, clearUserInfo])
 
+    useEffect(() => {
+        if (window.parent === window) {
+            return
+        }
+
+        let frameId = 0
+        let timeoutId: number | null = null
+        let lastReportedHeight = 0
+        let lastReportedAt = 0
+
+        const measureHeight = () =>
+            Math.max(
+                document.body.scrollHeight,
+                document.documentElement.scrollHeight,
+                document.body.offsetHeight,
+                document.documentElement.offsetHeight,
+            )
+
+        const postHeight = (height: number) => {
+            lastReportedHeight = height
+            lastReportedAt = Date.now()
+            window.parent.postMessage(
+                {
+                    type: HOST_HEIGHT_MESSAGE,
+                    payload: {
+                        height,
+                    },
+                },
+                '*',
+            )
+        }
+
+        const flushPostHeight = () => {
+            frameId = 0
+
+            const nextHeight = measureHeight()
+            if (nextHeight === lastReportedHeight) {
+                return
+            }
+
+            const elapsed = Date.now() - lastReportedAt
+            if (elapsed >= HOST_HEIGHT_REPORT_INTERVAL) {
+                postHeight(nextHeight)
+                return
+            }
+
+            if (timeoutId != null) {
+                return
+            }
+
+            timeoutId = window.setTimeout(() => {
+                timeoutId = null
+                postHeight(measureHeight())
+            }, HOST_HEIGHT_REPORT_INTERVAL - elapsed)
+        }
+
+        const schedulePostHeight = () => {
+            if (frameId) {
+                window.cancelAnimationFrame(frameId)
+            }
+
+            frameId = window.requestAnimationFrame(() => {
+                flushPostHeight()
+            })
+        }
+
+        schedulePostHeight()
+
+        const resizeObserver = new ResizeObserver(() => {
+            schedulePostHeight()
+        })
+
+        resizeObserver.observe(document.body)
+        resizeObserver.observe(document.documentElement)
+
+        window.addEventListener('load', schedulePostHeight)
+        window.addEventListener('resize', schedulePostHeight)
+
+        return () => {
+            resizeObserver.disconnect()
+            window.removeEventListener('load', schedulePostHeight)
+            window.removeEventListener('resize', schedulePostHeight)
+            if (frameId) {
+                window.cancelAnimationFrame(frameId)
+            }
+            if (timeoutId != null) {
+                window.clearTimeout(timeoutId)
+            }
+        }
+    }, [])
+
     if (!username || authBootstrapQuery.isPending) {
         return (
             <div className="flex min-h-screen items-center justify-center bg-[#08070E] px-6 text-center text-[14px] text-white/68">