diff --git a/apps/stage-web/package.json b/apps/stage-web/package.json
index 085a803a6..f729f87a3 100644
--- a/apps/stage-web/package.json
+++ b/apps/stage-web/package.json
@@ -71,6 +71,7 @@
     "driver.js": "catalog:",
     "drizzle-orm": "catalog:",
     "embla-carousel-vue": "catalog:",
+    "es-toolkit": "catalog:",
     "gpuu": "catalog:",
     "hono": "catalog:",
     "html2canvas": "catalog:",
diff --git a/apps/stage-web/src/components/Devtools/PerformanceOverlay.vue b/apps/stage-web/src/components/Devtools/PerformanceOverlay.vue
index 39783683e..0f2518f62 100644
--- a/apps/stage-web/src/components/Devtools/PerformanceOverlay.vue
+++ b/apps/stage-web/src/components/Devtools/PerformanceOverlay.vue
@@ -1,24 +1,46 @@
 <script setup lang="ts">
 import type { LagMetric } from '../../stores/devtools-lag'
 
+import { Button, IconButton } from '@proj-airi/ui'
+import { useDraggable, useElementBounding } from '@vueuse/core'
+import { clamp } from 'es-toolkit/math'
 import { storeToRefs } from 'pinia'
-import { computed, ref } from 'vue'
+import { computed, shallowRef, useTemplateRef, watch } from 'vue'
+import { useI18n } from 'vue-i18n'
 
 import { useDevtoolsLagStore } from '../../stores/devtools-lag'
 
+const { n, t } = useI18n()
 const store = useDevtoolsLagStore()
-const { enabled, buffers, recording } = storeToRefs(store)
+const { enabled, buffers, lastRecording, recording, recordingElapsedMs, supported } = storeToRefs(store)
 
-const hovered = ref(false)
+const dragBoundary = useTemplateRef<HTMLElement>('dragBoundary')
+const overlay = useTemplateRef<HTMLElement>('overlay')
+const dragHandle = useTemplateRef<HTMLElement>('dragHandle')
+const positionInitialized = shallowRef(false)
 
-const metrics: Array<{ key: LagMetric, label: string, enabled: () => boolean }> = [
-  { key: 'fps', label: 'FPS', enabled: () => enabled.value.fps },
-  { key: 'frameDuration', label: 'Frame (ms)', enabled: () => enabled.value.frameDuration },
-  { key: 'longtask', label: 'Long task (ms)', enabled: () => enabled.value.longtask },
-  { key: 'memory', label: 'Memory (MB)', enabled: () => enabled.value.memory },
+const metrics: Array<{ key: LagMetric, labelKey: string }> = [
+  {
+    key: 'fps',
+    labelKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.fps.label',
+  },
+  {
+    key: 'frameDuration',
+    labelKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.frame-duration.label',
+  },
+  {
+    key: 'longtask',
+    labelKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.long-task.label',
+  },
+  {
+    key: 'memory',
+    labelKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.memory.label',
+  },
 ]
 
-const visibleMetrics = computed(() => metrics.filter(metric => metric.enabled()))
+const visibleMetrics = computed(() => metrics.filter(metric => (
+  enabled.value[metric.key] && supported.value[metric.key]
+)))
 const hasAnyEnabled = computed(() => visibleMetrics.value.length > 0)
 const metricStatsMap = computed<Record<LagMetric, ReturnType<typeof store.calcStats>>>(() => {
   const result = {} as Record<LagMetric, ReturnType<typeof store.calcStats>>
@@ -30,20 +52,66 @@ const metricStatsMap = computed<Record<LagMetric, ReturnType<typeof store.calcSt
 })
 const metricsWithStats = computed(() => visibleMetrics.value.map(metric => ({
   ...metric,
+  hasSamples: buffers.value[metric.key].length > 0,
   stats: metricStatsMap.value[metric.key],
 })))
+const recordingElapsedSeconds = computed(() => Math.min(60, Math.floor(recordingElapsedMs.value / 1000)))
+const recordingButtonLabel = computed(() => recording.value
+  ? t('tamagotchi.settings.devtools.pages.performance-visualizer.overlay.stop')
+  : t('tamagotchi.settings.devtools.pages.performance-visualizer.overlay.record'))
 
-function formatValue(metric: string, value: number) {
+const { width: boundaryWidth, height: boundaryHeight } = useElementBounding(dragBoundary)
+const { width: overlayWidth, height: overlayHeight } = useElementBounding(overlay)
+const { position, isDragging } = useDraggable(overlay, {
+  containerElement: dragBoundary,
+  handle: dragHandle,
+  preventDefault: true,
+  restrictInView: true,
+  onEnd() {
+    positionInitialized.value = true
+    clampPosition()
+  },
+})
+
+const overlayPosition = computed(() => ({
+  left: `${position.value.x}px`,
+  top: `${position.value.y}px`,
+}))
+
+watch(
+  [hasAnyEnabled, boundaryWidth, boundaryHeight, overlayWidth, overlayHeight],
+  ([visible, availableWidth, availableHeight, currentWidth, currentHeight]) => {
+    if (!visible || availableWidth <= 0 || availableHeight <= 0 || currentWidth <= 0 || currentHeight <= 0)
+      return
+
+    if (!positionInitialized.value) {
+      resetPosition()
+      return
+    }
+
+    clampPosition()
+  },
+  { flush: 'post' },
+)
+
+function formatValue(metric: LagMetric, value: number) {
   if (!Number.isFinite(value))
     return '--'
 
-  if (metric === 'memory')
-    return `${(value / 1048576).toFixed(1)}`
+  if (metric === 'memory') {
+    return n(value / 1048576, {
+      minimumFractionDigits: 1,
+      maximumFractionDigits: 1,
+    })
+  }
 
   if (metric === 'fps')
-    return value.toFixed(0)
+    return n(value, { maximumFractionDigits: 0 })
 
-  return value.toFixed(1)
+  return n(value, {
+    minimumFractionDigits: 1,
+    maximumFractionDigits: 1,
+  })
 }
 
 function barSeries(metric: LagMetric) {
@@ -56,72 +124,133 @@ function barSeries(metric: LagMetric) {
   }))
 }
 
-function toggleRecording() {
-  if (recording.value) {
-    const snapshot = store.stopRecording()
-    if (snapshot)
-      store.exportCsv(snapshot)
-    return
-  }
+function clampPosition(nextX = position.value.x, nextY = position.value.y) {
+  const maxX = Math.max(0, boundaryWidth.value - overlayWidth.value)
+  const maxY = Math.max(0, boundaryHeight.value - overlayHeight.value)
 
-  store.startRecording()
+  position.value = {
+    x: clamp(nextX, 0, maxX),
+    y: clamp(nextY, 0, maxY),
+  }
+}
+
+function resetPosition() {
+  clampPosition(0, boundaryHeight.value - overlayHeight.value)
+  positionInitialized.value = true
 }
 </script>
 
 <template>
-  <div
-    v-if="hasAnyEnabled"
-    :style="{ opacity: hovered ? 1 : 0.3 }"
-    class="fixed bottom-3 left-3 z-50"
-    p-3
-    flex="~ col gap-2"
-    rounded="xl"
-    bg="neutral-900/80"
-    text="white sm"
-    shadow="xl"
-    transition="opacity 200ms ease"
-    @mouseenter="hovered = true"
-    @mouseleave="hovered = false"
-  >
-    <div flex="~ row items-center gap-2" justify-between>
-      <div text="xs neutral-200" uppercase tracking="wide">
-        Performance Overlay
-      </div>
-      <button
-        type="button"
-        class="inline-flex items-center gap-1 rounded bg-white/10 px-2 py-1 text-xs transition-colors hover:bg-white/20"
-        @click="toggleRecording"
+  <Teleport to="body">
+    <div
+      v-if="hasAnyEnabled"
+      ref="dragBoundary"
+      :style="{
+        top: 'calc(env(safe-area-inset-top, 0px) + 0.75rem)',
+        right: 'calc(env(safe-area-inset-right, 0px) + 0.75rem)',
+        bottom: 'calc(env(safe-area-inset-bottom, 0px) + 0.75rem)',
+        left: 'calc(env(safe-area-inset-left, 0px) + 0.75rem)',
+      }"
+      :class="['pointer-events-none fixed z-[900]']"
+    >
+      <section
+        ref="overlay"
+        data-testid="performance-overlay"
+        :style="overlayPosition"
+        :class="[
+          'pointer-events-auto absolute w-72 max-h-full max-w-full overflow-y-auto rounded-xl p-3',
+          'flex flex-col gap-2',
+          'bg-neutral-950/92 text-sm text-white shadow-xl backdrop-blur-lg',
+          'transition-opacity duration-150 ease-out motion-reduce:transition-none',
+          positionInitialized ? 'opacity-100' : 'opacity-0',
+          isDragging ? 'select-none' : '',
+        ]"
       >
-        <span
-          class="inline-block h-2 w-2 rounded-full"
-          :class="recording ? 'bg-red-400' : 'bg-neutral-400'"
-        />
-        <span>{{ recording ? 'Stop' : 'Record' }}</span>
-      </button>
-    </div>
+        <header :class="['flex items-center gap-2']">
+          <div
+            ref="dragHandle"
+            :class="[
+              'shrink-0 touch-none select-none',
+              isDragging ? 'cursor-grabbing' : 'cursor-grab',
+            ]"
+          >
+            <IconButton
+              icon="i-solar:menu-dots-bold-duotone"
+              :aria-label="t('tamagotchi.settings.devtools.pages.performance-visualizer.overlay.move')"
+              :title="t('tamagotchi.settings.devtools.pages.performance-visualizer.overlay.move')"
+            />
+          </div>
+          <div :class="['min-w-0 flex-1 truncate text-xs font-medium text-neutral-200 uppercase tracking-wide']">
+            {{ t('tamagotchi.settings.devtools.pages.performance-visualizer.overlay.title') }}
+          </div>
+          <IconButton
+            icon="i-solar:restart-bold-duotone"
+            :aria-label="t('tamagotchi.settings.devtools.pages.performance-visualizer.overlay.reset-position')"
+            :title="t('tamagotchi.settings.devtools.pages.performance-visualizer.overlay.reset-position')"
+            @click="resetPosition"
+          />
+        </header>
 
-    <div v-for="metric in metricsWithStats" :key="metric.key" flex="~ col gap-1">
-      <div flex="~ row items-center justify-between">
-        <span text="xs neutral-100">{{ metric.label }}</span>
-        <span text="xs neutral-300">
-          <template v-if="metric.stats.latest">
-            avg {{ formatValue(metric.key, metric.stats.avg) }}
-            /
-            p95 {{ formatValue(metric.key, metric.stats.p95) }}
-          </template>
-          <template v-else>
-            --
-          </template>
-        </span>
-      </div>
-      <div class="h-10 flex items-end gap-0.5 overflow-hidden rounded bg-white/5 px-1 py-1">
         <div
-          v-for="(bar, index) in barSeries(metric.key)"
-          :key="index"
-          :style="{ width: bar.width, height: bar.height }"
-          class="bg-white/50"
-        />
-      </div>
+          v-for="metric in metricsWithStats"
+          :key="metric.key"
+          :class="['flex flex-col gap-1']"
+        >
+          <div :class="['flex items-center justify-between gap-3']">
+            <span :class="['min-w-0 truncate text-xs text-neutral-100']">
+              {{ t(metric.labelKey) }}
+            </span>
+            <span :class="['shrink-0 font-mono text-xs text-neutral-300 tabular-nums']">
+              <template v-if="metric.hasSamples">
+                {{ t('tamagotchi.settings.devtools.pages.performance-visualizer.overlay.average') }}
+                {{ formatValue(metric.key, metric.stats.avg) }}
+                /
+                p95 {{ formatValue(metric.key, metric.stats.p95) }}
+              </template>
+              <template v-else>
+                --
+              </template>
+            </span>
+          </div>
+          <div
+            :class="['h-10 overflow-hidden rounded bg-white/5 px-1 py-1', 'flex items-end gap-0.5']"
+            aria-hidden="true"
+          >
+            <div
+              v-for="(bar, index) in barSeries(metric.key)"
+              :key="index"
+              :style="{ width: bar.width, height: bar.height }"
+              :class="['bg-white/50']"
+            />
+          </div>
+        </div>
+
+        <footer :class="['flex items-center gap-2 pt-2']">
+          <Button
+            size="sm"
+            :icon="recording ? 'i-solar:stop-circle-bold-duotone' : 'i-solar:record-circle-bold-duotone'"
+            :label="recordingButtonLabel"
+            :color="recording ? 'red' : 'neutral'"
+            :outline="false"
+            @click="store.toggleRecording"
+          />
+          <span
+            v-if="recording"
+            :class="['font-mono text-xs text-neutral-300 tabular-nums']"
+            aria-hidden="true"
+          >
+            {{ n(recordingElapsedSeconds) }}s / 60s
+          </span>
+          <span v-else :class="['flex-1']" />
+          <IconButton
+            icon="i-solar:export-bold-duotone"
+            :disabled="!lastRecording"
+            :aria-label="t('tamagotchi.settings.devtools.pages.performance-visualizer.overlay.export')"
+            :title="t('tamagotchi.settings.devtools.pages.performance-visualizer.overlay.export')"
+            @click="store.exportCsv()"
+          />
+        </footer>
+      </section>
     </div>
-  </div>
+  </Teleport>
 </template>
diff --git a/apps/stage-web/src/components/Devtools/performance-overlay.browser.test.ts b/apps/stage-web/src/components/Devtools/performance-overlay.browser.test.ts
new file mode 100644
index 000000000..9cf740028
--- /dev/null
+++ b/apps/stage-web/src/components/Devtools/performance-overlay.browser.test.ts
@@ -0,0 +1,50 @@
+import en from '@proj-airi/i18n/locales/en'
+
+import { createPinia } from 'pinia'
+import { describe, expect, it, vi } from 'vitest'
+import { render } from 'vitest-browser-vue'
+import { createI18n } from 'vue-i18n'
+
+import PerformanceOverlay from './PerformanceOverlay.vue'
+
+import { useDevtoolsLagStore } from '../../stores/devtools-lag'
+
+import 'virtual:uno.css'
+
+describe('performance overlay recording controls', () => {
+  it('keeps CSV export separate from stopping a recording', async () => {
+    // ROOT CAUSE:
+    //
+    // The overlay exported a CSV file when the user stopped a recording.
+    // The settings page only saved the recording, so the same action had two
+    // different outcomes. We keep export as a separate explicit action.
+    const pinia = createPinia()
+    const store = useDevtoolsLagStore(pinia)
+    const exportCsv = vi.spyOn(store, 'exportCsv')
+    store.enabled.fps = true
+
+    const screen = await render(PerformanceOverlay, {
+      global: {
+        plugins: [
+          pinia,
+          createI18n({
+            legacy: false,
+            locale: 'en',
+            messages: {
+              en,
+            },
+          }),
+        ],
+      },
+    })
+
+    await screen.getByRole('button', { name: 'Record', exact: true }).click()
+    expect(store.recording).toBe(true)
+
+    await screen.getByRole('button', { name: 'Stop', exact: true }).click()
+    expect(store.recording).toBe(false)
+    expect(exportCsv).not.toHaveBeenCalled()
+
+    store.toggleAll(false)
+  })
+})
diff --git a/apps/stage-web/src/composables/perf/register-lag-sampler.ts b/apps/stage-web/src/composables/perf/register-lag-sampler.ts
index 092316909..298b26f51 100644
--- a/apps/stage-web/src/composables/perf/register-lag-sampler.ts
+++ b/apps/stage-web/src/composables/perf/register-lag-sampler.ts
@@ -7,12 +7,28 @@ interface LagEnabled {
   memory: boolean
 }
 
+type LagMetricSupport = Readonly<Record<keyof LagEnabled, boolean>>
+
+/**
+ * Creates a browser-local sampler for live performance metrics.
+ *
+ * Unsupported metrics stay disabled because their Web APIs do not produce
+ * comparable fallback values.
+ */
 export function createLagSampler(tracer: PerfTracer) {
   let rafId: number | undefined
   let lastTs: number | undefined
   let longTaskObserver: PerformanceObserver | undefined
   let memoryTimer: ReturnType<typeof setInterval> | undefined
 
+  const supported: LagMetricSupport = {
+    fps: typeof requestAnimationFrame === 'function',
+    frameDuration: typeof requestAnimationFrame === 'function',
+    longtask: typeof PerformanceObserver !== 'undefined'
+      && PerformanceObserver.supportedEntryTypes.includes('longtask'),
+    memory: typeof performance !== 'undefined' && 'memory' in performance,
+  }
+
   function stopRaf() {
     if (rafId !== undefined) {
       cancelAnimationFrame(rafId)
@@ -58,7 +74,7 @@ export function createLagSampler(tracer: PerfTracer) {
 
   function startLongTaskObserver() {
     stopLongTaskObserver()
-    if (!('PerformanceObserver' in window))
+    if (!supported.longtask)
       return
 
     try {
@@ -89,7 +105,7 @@ export function createLagSampler(tracer: PerfTracer) {
   function startMemoryTimer() {
     stopMemoryTimer()
     const perfWithMemory = performance as Performance & { memory?: { usedJSHeapSize: number } }
-    if (!perfWithMemory.memory)
+    if (!supported.memory || !perfWithMemory.memory)
       return
 
     memoryTimer = setInterval(() => {
@@ -105,13 +121,13 @@ export function createLagSampler(tracer: PerfTracer) {
   function start(enabled: LagEnabled) {
     stop()
 
-    if (enabled.fps || enabled.frameDuration)
+    if ((enabled.fps && supported.fps) || (enabled.frameDuration && supported.frameDuration))
       startRaf()
 
-    if (enabled.longtask)
+    if (enabled.longtask && supported.longtask)
       startLongTaskObserver()
 
-    if (enabled.memory)
+    if (enabled.memory && supported.memory)
       startMemoryTimer()
   }
 
@@ -122,6 +138,7 @@ export function createLagSampler(tracer: PerfTracer) {
   }
 
   return {
+    supported,
     start,
     stop,
   }
diff --git a/apps/stage-web/src/pages/devtools/performance-visualizer.vue b/apps/stage-web/src/pages/devtools/performance-visualizer.vue
index eafa829ee..da8fdfab5 100644
--- a/apps/stage-web/src/pages/devtools/performance-visualizer.vue
+++ b/apps/stage-web/src/pages/devtools/performance-visualizer.vue
@@ -1,111 +1,161 @@
 <script setup lang="ts">
-import { ButtonBar, CheckBar } from '@proj-airi/stage-ui/components'
+import type { LagMetric } from '../../stores/devtools-lag'
+
+import { Button, FieldCheckbox } from '@proj-airi/ui'
 import { useMagicKeys, whenever } from '@vueuse/core'
 import { storeToRefs } from 'pinia'
 import { computed } from 'vue'
+import { useI18n } from 'vue-i18n'
 
 import { useDevtoolsLagStore } from '../../stores/devtools-lag'
 
+const { n, t } = useI18n()
 const lagStore = useDevtoolsLagStore()
-const { enabled, lastRecording, recording } = storeToRefs(lagStore)
+const { enabled, lastRecording, recording, recordingElapsedMs, supported } = storeToRefs(lagStore)
 
-const recordingLabel = computed(() => recording.value ? 'Stop recording (max 60s)' : 'Start recording')
+const metricDefinitions: Array<{
+  key: LagMetric
+  labelKey: string
+  descriptionKey: string
+  unsupportedKey?: string
+}> = [
+  {
+    key: 'fps',
+    labelKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.fps.label',
+    descriptionKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.fps.description',
+  },
+  {
+    key: 'frameDuration',
+    labelKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.frame-duration.label',
+    descriptionKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.frame-duration.description',
+  },
+  {
+    key: 'longtask',
+    labelKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.long-task.label',
+    descriptionKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.long-task.description',
+    unsupportedKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.long-task.unsupported',
+  },
+  {
+    key: 'memory',
+    labelKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.memory.label',
+    descriptionKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.memory.description',
+    unsupportedKey: 'tamagotchi.settings.devtools.pages.performance-visualizer.metrics.memory.unsupported',
+  },
+]
+
+const metricControls = computed(() => metricDefinitions.map(metric => ({
+  ...metric,
+  supported: supported.value[metric.key],
+})))
+const recordingElapsedSeconds = computed(() => Math.min(60, Math.floor(recordingElapsedMs.value / 1000)))
+const recordingLabel = computed(() => recording.value
+  ? t('tamagotchi.settings.devtools.pages.performance-visualizer.controls.stop-recording', { seconds: recordingElapsedSeconds.value })
+  : t('tamagotchi.settings.devtools.pages.performance-visualizer.controls.start-recording'))
 const hasRecording = computed(() => !!lastRecording.value)
-const allEnabled = computed(() => enabled.value.fps && enabled.value.frameDuration && enabled.value.longtask && enabled.value.memory)
+const allEnabled = computed({
+  get() {
+    const supportedMetrics = metricDefinitions.filter(metric => supported.value[metric.key])
+    return supportedMetrics.length > 0
+      && supportedMetrics.every(metric => enabled.value[metric.key])
+  },
+  set(value: boolean) {
+    lagStore.toggleAll(value)
+  },
+})
 
 const magicKeys = useMagicKeys()
-whenever(magicKeys['ctrl+alt+l'], () => toggleAll(true))
-whenever(magicKeys['ctrl+alt+k'], () => toggleAll(false))
-
-function toggleAll(on: boolean) {
-  lagStore.toggleAll(on)
-}
+whenever(magicKeys['ctrl+alt+l'], () => lagStore.toggleAll(true))
+whenever(magicKeys['ctrl+alt+k'], () => lagStore.toggleAll(false))
 
 function exportCsv() {
   lagStore.exportCsv()
 }
+
+function metricDescription(metric: typeof metricControls.value[number]) {
+  if (metric.supported || !metric.unsupportedKey)
+    return t(metric.descriptionKey)
+
+  return t(metric.unsupportedKey)
+}
 </script>
 
 <template>
-  <div flex="~ col gap-4" pb-6>
-    <div flex="~ col gap-2">
-      <div flex="~ row items-center gap-2">
-        <CheckBar
-          :model-value="allEnabled"
-          icon-on="i-solar:sledgehammer-bold-duotone"
-          icon-off="i-solar:sledgehammer-bold-duotone"
-          text="Enable all metrics"
-          description="Toggle all lag metrics (FPS, frame time, long task, memory)"
-          @update:model-value="value => toggleAll(Boolean(value))"
-        />
-        <ButtonBar
-          :icon="recording ? 'i-solar:stop-circle-bold-duotone' : 'i-solar:recive-bold-duotone'"
-          text="Recording"
-          @click="recording ? lagStore.stopRecording() : lagStore.startRecording()"
-        >
-          {{ recordingLabel }}
-        </ButtonBar>
-        <ButtonBar
-          icon="i-solar:export-bold-duotone"
-          text="Export CSV"
-          :disabled="!hasRecording"
-          @click="exportCsv"
-        >
-          Export last recording
-        </ButtonBar>
-      </div>
+  <div :class="['flex flex-col gap-4', 'pb-6']">
+    <section
+      :class="[
+        'rounded-2xl p-4',
+        'bg-neutral-50/80 dark:bg-neutral-900/50',
+      ]"
+    >
+      <FieldCheckbox
+        v-model="allEnabled"
+        :label="t('tamagotchi.settings.devtools.pages.performance-visualizer.controls.enable-all.label')"
+        :description="t('tamagotchi.settings.devtools.pages.performance-visualizer.controls.enable-all.description')"
+      />
+    </section>
 
-      <div flex="~ col gap-2">
-        <CheckBar
-          v-model="enabled.fps"
-          icon-on="i-solar:activity-bold-duotone"
-          icon-off="i-solar:activity-bold-duotone"
-          text="FPS"
-          description="Collect FPS histogram"
-        />
-        <CheckBar
-          v-model="enabled.frameDuration"
-          icon-on="i-solar:chart-bold-duotone"
-          icon-off="i-solar:chart-bold-duotone"
-          text="Frame time (ms)"
-          description="Collect frame duration histogram"
-        />
-        <CheckBar
-          v-model="enabled.longtask"
-          icon-on="i-solar:timer-bold-duotone"
-          icon-off="i-solar:timer-bold-duotone"
-          text="Long tasks"
-          description="PerformanceObserver('longtask')"
-        />
-        <CheckBar
-          v-model="enabled.memory"
-          icon-on="i-solar:database-bold-duotone"
-          icon-off="i-solar:database-bold-duotone"
-          text="Memory"
-          description="Sample performance.memory every second"
-        />
-      </div>
+    <div :class="['flex flex-wrap items-center gap-2']">
+      <Button
+        :icon="recording ? 'i-solar:stop-circle-bold-duotone' : 'i-solar:record-circle-bold-duotone'"
+        :label="recordingLabel"
+        :color="recording ? 'red' : 'primary'"
+        variant="secondary"
+        @click="lagStore.toggleRecording"
+      />
+      <Button
+        icon="i-solar:export-bold-duotone"
+        :label="t('tamagotchi.settings.devtools.pages.performance-visualizer.controls.export-last-recording')"
+        :disabled="!hasRecording"
+        @click="exportCsv"
+      />
+      <span :class="['text-xs text-neutral-500 dark:text-neutral-400']">
+        {{ t('tamagotchi.settings.devtools.pages.performance-visualizer.recording.limit') }}
+      </span>
     </div>
 
-    <div v-if="hasRecording" flex="~ col gap-2" rounded="lg" border="1 dashed neutral-700" p-3>
-      <div text="sm neutral-200">
-        Last recording
-      </div>
-      <div text="xs neutral-400">
-        Started at {{ lastRecording?.startedAt.toFixed(0) }} ms, duration
-        {{ (lastRecording!.stoppedAt - lastRecording!.startedAt).toFixed(0) }} ms
-      </div>
-      <div text="xs neutral-400">
-        Samples:
-        FPS {{ lastRecording?.samples.fps.length }},
-        Frames {{ lastRecording?.samples.frameDuration.length }},
-        Long tasks {{ lastRecording?.samples.longtask.length }},
-        Memory {{ lastRecording?.samples.memory.length }}
-      </div>
+    <div :class="['grid gap-3', 'md:grid-cols-2']">
+      <section
+        v-for="metric in metricControls"
+        :key="metric.key"
+        :class="[
+          'min-w-0 rounded-2xl p-4',
+          'bg-neutral-50/80 dark:bg-neutral-900/50',
+        ]"
+      >
+        <FieldCheckbox
+          v-model="enabled[metric.key]"
+          :label="t(metric.labelKey)"
+          :description="metricDescription(metric)"
+          :disabled="!metric.supported"
+        />
+      </section>
     </div>
 
-    <div text="xs neutral-500">
-      Overlay is visible when any metric is enabled. Recording caps at 60s.
+    <section
+      v-if="lastRecording"
+      :class="[
+        'flex flex-col gap-2 rounded-2xl p-4',
+        'border border-dashed border-neutral-300 dark:border-neutral-700',
+      ]"
+    >
+      <div :class="['text-sm font-medium text-neutral-800 dark:text-neutral-200']">
+        {{ t('tamagotchi.settings.devtools.pages.performance-visualizer.recording.title') }}
+      </div>
+      <div :class="['text-xs text-neutral-500 dark:text-neutral-400']">
+        {{ t('tamagotchi.settings.devtools.pages.performance-visualizer.recording.duration', {
+          duration: n(lastRecording.stoppedAt - lastRecording.startedAt, { maximumFractionDigits: 0 }),
+        }) }}
+      </div>
+      <div :class="['grid gap-1 text-xs text-neutral-500 dark:text-neutral-400', 'sm:grid-cols-2 lg:grid-cols-4']">
+        <span>{{ t('tamagotchi.settings.devtools.pages.performance-visualizer.metrics.fps.label') }}: {{ n(lastRecording.samples.fps.length) }}</span>
+        <span>{{ t('tamagotchi.settings.devtools.pages.performance-visualizer.metrics.frame-duration.label') }}: {{ n(lastRecording.samples.frameDuration.length) }}</span>
+        <span>{{ t('tamagotchi.settings.devtools.pages.performance-visualizer.metrics.long-task.label') }}: {{ n(lastRecording.samples.longtask.length) }}</span>
+        <span>{{ t('tamagotchi.settings.devtools.pages.performance-visualizer.metrics.memory.label') }}: {{ n(lastRecording.samples.memory.length) }}</span>
+      </div>
+    </section>
+
+    <div :class="['text-xs text-neutral-500 dark:text-neutral-400']">
+      {{ t('tamagotchi.settings.devtools.pages.performance-visualizer.description') }}
     </div>
   </div>
 </template>
diff --git a/apps/stage-web/src/stores/devtools-lag.ts b/apps/stage-web/src/stores/devtools-lag.ts
index 6acc5bc19..7c3efe1df 100644
--- a/apps/stage-web/src/stores/devtools-lag.ts
+++ b/apps/stage-web/src/stores/devtools-lag.ts
@@ -2,7 +2,7 @@ import type { TraceEvent } from '@proj-airi/stage-shared'
 
 import { defaultPerfTracer, exportCsv as exportCsvFile } from '@proj-airi/stage-shared'
 import { defineStore } from 'pinia'
-import { reactive, ref, watch } from 'vue'
+import { onScopeDispose, reactive, ref, shallowRef, watch } from 'vue'
 
 import { createLagSampler } from '../composables/perf/register-lag-sampler'
 
@@ -11,7 +11,7 @@ export type LagMetric = 'fps' | 'frameDuration' | 'longtask' | 'memory'
 interface Sample {
   ts: number
   value: number
-  meta?: Record<string, any>
+  meta?: Record<string, unknown>
 }
 
 interface RecordingSnapshot {
@@ -49,7 +49,7 @@ function calcStats(values: number[]) {
   const sorted = [...values].sort((a, b) => a - b)
   const idx = Math.max(0, Math.floor(0.95 * (sorted.length - 1)))
   const p95 = sorted[idx]
-  const latest = values.at(-1)
+  const latest = values.at(-1) ?? 0
 
   return { avg, p95, latest }
 }
@@ -99,11 +99,14 @@ export const useDevtoolsLagStore = defineStore('devtoolsLag', () => {
 
   const recording = ref(false)
   const recordingStartedAt = ref<number | null>(null)
+  const recordingElapsedMs = ref(0)
   const recordingSamples = reactive(createEmptySamples())
   const lastRecording = ref<RecordingSnapshot>()
   let recordingTimeout: ReturnType<typeof setTimeout> | undefined
+  let recordingElapsedTimer: ReturnType<typeof setInterval> | undefined
 
   const sampler = createLagSampler(defaultPerfTracer)
+  const supported = shallowRef(sampler.supported)
   let unsubscribeTracer: (() => void) | undefined
   let releaseTracer: (() => void) | undefined
 
@@ -112,7 +115,7 @@ export const useDevtoolsLagStore = defineStore('devtoolsLag', () => {
       recordingSamples[metric] = []
   }
 
-  function applySample(metric: LagMetric, value: number, meta?: Record<string, any>) {
+  function applySample(metric: LagMetric, value: number, meta?: Record<string, unknown>) {
     const ts = performance.now()
     const cutoff = ts - windowMs
 
@@ -132,8 +135,15 @@ export const useDevtoolsLagStore = defineStore('devtoolsLag', () => {
 
     recording.value = true
     recordingStartedAt.value = performance.now()
+    recordingElapsedMs.value = 0
     resetRecordingSamples()
 
+    recordingElapsedTimer = setInterval(() => {
+      if (recordingStartedAt.value === null)
+        return
+
+      recordingElapsedMs.value = performance.now() - recordingStartedAt.value
+    }, 1000)
     recordingTimeout = setTimeout(stopRecording, 60000)
   }
 
@@ -145,10 +155,17 @@ export const useDevtoolsLagStore = defineStore('devtoolsLag', () => {
       clearTimeout(recordingTimeout)
       recordingTimeout = undefined
     }
+    if (recordingElapsedTimer) {
+      clearInterval(recordingElapsedTimer)
+      recordingElapsedTimer = undefined
+    }
 
     const stoppedAt = performance.now()
+    recordingElapsedMs.value = recordingStartedAt.value === null
+      ? 0
+      : stoppedAt - recordingStartedAt.value
     const snapshot: RecordingSnapshot = {
-      startedAt: recordingStartedAt.value || stoppedAt,
+      startedAt: recordingStartedAt.value ?? stoppedAt,
       stoppedAt,
       samples: {
         fps: [...recordingSamples.fps],
@@ -165,6 +182,13 @@ export const useDevtoolsLagStore = defineStore('devtoolsLag', () => {
     return snapshot
   }
 
+  function toggleRecording(): RecordingSnapshot | undefined {
+    if (recording.value)
+      return stopRecording()
+
+    startRecording()
+  }
+
   function stopAll() {
     sampler.stop()
     if (unsubscribeTracer) {
@@ -176,7 +200,10 @@ export const useDevtoolsLagStore = defineStore('devtoolsLag', () => {
   }
 
   function ensureSampler() {
-    const anyEnabled = enabled.fps || enabled.frameDuration || enabled.longtask || enabled.memory
+    const anyEnabled = (enabled.fps && supported.value.fps)
+      || (enabled.frameDuration && supported.value.frameDuration)
+      || (enabled.longtask && supported.value.longtask)
+      || (enabled.memory && supported.value.memory)
     if (!anyEnabled) {
       stopAll()
       return
@@ -206,18 +233,18 @@ export const useDevtoolsLagStore = defineStore('devtoolsLag', () => {
     if (!releaseTracer)
       releaseTracer = defaultPerfTracer.acquire('lag-overlay')
     sampler.start({
-      fps: enabled.fps,
-      frameDuration: enabled.frameDuration,
-      longtask: enabled.longtask,
-      memory: enabled.memory,
+      fps: enabled.fps && supported.value.fps,
+      frameDuration: enabled.frameDuration && supported.value.frameDuration,
+      longtask: enabled.longtask && supported.value.longtask,
+      memory: enabled.memory && supported.value.memory,
     })
   }
 
   function toggleAll(on: boolean) {
-    enabled.fps = on
-    enabled.frameDuration = on
-    enabled.longtask = on
-    enabled.memory = on
+    enabled.fps = on && supported.value.fps
+    enabled.frameDuration = on && supported.value.frameDuration
+    enabled.longtask = on && supported.value.longtask
+    enabled.memory = on && supported.value.memory
     ensureSampler()
   }
 
@@ -250,11 +277,16 @@ export const useDevtoolsLagStore = defineStore('devtoolsLag', () => {
     { deep: true },
   )
 
-  // Cleanup on tab close
+  function dispose() {
+    stopRecording()
+    stopAll()
+  }
+
   if (typeof window !== 'undefined') {
-    window.addEventListener('beforeunload', () => {
-      stopRecording()
-      stopAll()
+    window.addEventListener('beforeunload', dispose)
+    onScopeDispose(() => {
+      window.removeEventListener('beforeunload', dispose)
+      dispose()
     })
   }
 
@@ -262,9 +294,12 @@ export const useDevtoolsLagStore = defineStore('devtoolsLag', () => {
     enabled,
     buffers,
     recording,
+    recordingElapsedMs,
     lastRecording,
+    supported,
     startRecording,
     stopRecording,
+    toggleRecording,
     exportCsv,
     toggleAll,
     calcStats,
diff --git a/packages/i18n/src/locales/en/settings.yaml b/packages/i18n/src/locales/en/settings.yaml
index 1337bb80e..e020a1b4c 100644
--- a/packages/i18n/src/locales/en/settings.yaml
+++ b/packages/i18n/src/locales/en/settings.yaml
@@ -1542,7 +1542,7 @@ pages:
             section:
               performance-visualizer:
                 title: Performance Visualizer
-                description: Toggle FPS/long task/memory overlay
+                description: Show FPS, frame time, long tasks, and supported browser memory metrics
               markdown-stress:
                 title: Markdown Stress
                 description: Stress markdown parsing and rendering with heavy chat payloads
diff --git a/packages/i18n/src/locales/en/tamagotchi/settings.yaml b/packages/i18n/src/locales/en/tamagotchi/settings.yaml
index 94d137943..ae9dbed89 100644
--- a/packages/i18n/src/locales/en/tamagotchi/settings.yaml
+++ b/packages/i18n/src/locales/en/tamagotchi/settings.yaml
@@ -57,7 +57,41 @@ devtools:
       title: Lag Visualizer
     performance-visualizer:
       title: Performance Visualizer
-      description: Toggle FPS/long task/memory overlay
+      description: Inspect live performance metrics and runtime diagnostics
+      controls:
+        enable-all:
+          label: Enable all available metrics
+          description: Enable each metric that this browser supports.
+        start-recording: Start recording
+        stop-recording: Stop recording ({seconds}s)
+        export-last-recording: Export last recording
+      metrics:
+        fps:
+          label: FPS
+          description: Frames per second during the last 10 seconds.
+        frame-duration:
+          label: Frame time (ms)
+          description: Time between animation frames during the last 10 seconds.
+        long-task:
+          label: Long tasks
+          description: Main-thread tasks that take at least 50 ms.
+          unsupported: This browser does not expose long-task timing.
+        memory:
+          label: JS heap (MB)
+          description: JavaScript heap usage from Chromium's performance.memory API.
+          unsupported: This browser does not expose JavaScript heap usage.
+      recording:
+        title: Last recording
+        duration: Duration {duration} ms
+        limit: Recording stops after 60 seconds.
+      overlay:
+        title: Performance
+        move: Move performance overlay
+        reset-position: Reset overlay position
+        record: Record
+        stop: Stop
+        export: Export last recording
+        average: avg
     markdown-stress:
       title: Markdown Stress
       description: Stress markdown parsing and rendering with heavy chat payloads
diff --git a/packages/i18n/src/locales/zh-Hans/settings.yaml b/packages/i18n/src/locales/zh-Hans/settings.yaml
index 62f8a7e0b..60faa1903 100644
--- a/packages/i18n/src/locales/zh-Hans/settings.yaml
+++ b/packages/i18n/src/locales/zh-Hans/settings.yaml
@@ -1476,7 +1476,7 @@ pages:
             section:
               performance-visualizer:
                 title: 性能可视化工具
-                description: 切换 FPS/长任务/内存叠加
+                description: 显示 FPS、帧时间、长任务和浏览器支持的内存指标
               markdown-stress:
                 title: Markdown Stress
                 description: 用大量聊天负载来测试 Markdown 的解析和渲染能力
diff --git a/packages/i18n/src/locales/zh-Hans/tamagotchi/settings.yaml b/packages/i18n/src/locales/zh-Hans/tamagotchi/settings.yaml
index 8bc352096..beaf08f07 100644
--- a/packages/i18n/src/locales/zh-Hans/tamagotchi/settings.yaml
+++ b/packages/i18n/src/locales/zh-Hans/tamagotchi/settings.yaml
@@ -57,7 +57,41 @@ devtools:
       title: Lag 可视化
     performance-visualizer:
       title: 性能可视化
-      description: 切换 FPS/长任务/内存叠加
+      description: 检查实时性能指标和运行时诊断数据
+      controls:
+        enable-all:
+          label: 启用所有可用指标
+          description: 启用当前浏览器支持的所有指标。
+        start-recording: 开始录制
+        stop-recording: 停止录制（{seconds} 秒）
+        export-last-recording: 导出上次录制
+      metrics:
+        fps:
+          label: FPS
+          description: 最近 10 秒内的每秒帧数。
+        frame-duration:
+          label: 帧时间（毫秒）
+          description: 最近 10 秒内动画帧之间的时间。
+        long-task:
+          label: 长任务
+          description: 耗时至少 50 毫秒的主线程任务。
+          unsupported: 当前浏览器不提供长任务计时。
+        memory:
+          label: JS 堆（MB）
+          description: Chromium performance.memory API 提供的 JavaScript 堆用量。
+          unsupported: 当前浏览器不提供 JavaScript 堆用量。
+      recording:
+        title: 上次录制
+        duration: 时长 {duration} 毫秒
+        limit: 录制会在 60 秒后停止。
+      overlay:
+        title: 性能
+        move: 移动性能浮窗
+        reset-position: 重置浮窗位置
+        record: 录制
+        stop: 停止
+        export: 导出上次录制
+        average: 平均
     markdown-stress:
       title: Markdown 压力测试
       description: 用大量聊天负载来测试 Markdown 的解析和渲染能力
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index d4aeecf45..c6ece547f 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -2491,6 +2491,9 @@ importers:
       embla-carousel-vue:
         specifier: 'catalog:'
         version: 9.0.0-rc02(vue@3.5.32(typescript@5.9.3))
+      es-toolkit:
+        specifier: 'catalog:'
+        version: 1.50.0
       gpuu:
         specifier: 'catalog:'
         version: 1.0.7