diff --git a/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue b/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
index 68b902bd..5fd38bf5 100644
--- a/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
+++ b/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
@@ -28,14 +28,6 @@ const { following, keepBottomAfterUpdate, onScroll: onPanelScroll, scrollToBotto
 const detailMessageId = ref<string | null>(null);
 const displayedDurationFloorMs = new Map<string, number>();
 const sealedDurationMs = new Map<string, number>();
-type VisibleTimingSample = {
-  durationMs?: number;
-  durationObservedAtMs?: number;
-  lastEventAgeMs?: number;
-  lastEventObservedAtMs?: number;
-  lastEventSourceMs?: number;
-};
-const visibleTimingSamples = new Map<string, VisibleTimingSample>();
 const visibleMessages = computed(() => workbench.sessionDetailLoading ? [] : workbench.activeMessages);
 const hasRunningAgentMessages = computed(() => visibleMessages.value.some(isRunningMessage));
 const { nowMs } = useWorkbenchNowTicker(hasRunningAgentMessages);
@@ -74,9 +66,6 @@ watch(visibleMessages, (messages) => {
   for (const key of Array.from(sealedDurationMs.keys())) {
     if (!visibleKeys.has(key)) sealedDurationMs.delete(key);
   }
-  for (const key of Array.from(visibleTimingSamples.keys())) {
-    if (!visibleKeys.has(key)) visibleTimingSamples.delete(key);
-  }
 }, { immediate: true });
 
 function openDetails(message: ChatMessage): void {
@@ -280,12 +269,8 @@ function messageDurationMeta(message: ChatMessage): { text: string; label: strin
 function monotonicDisplayDurationMs(message: ChatMessage, durationMs: number | null): number | null {
   if (durationMs === null) return null;
   const key = messageDurationFloorKey(message);
-  const sample = visibleTimingSamples.get(key) ?? {};
-  const previous = sample.durationMs ?? displayedDurationFloorMs.get(key);
-  const next = smoothVisibleIncreasingDurationMs(previous, sample.durationObservedAtMs, durationMs, nowMs.value);
-  sample.durationMs = next;
-  sample.durationObservedAtMs = nowMs.value;
-  visibleTimingSamples.set(key, sample);
+  const previous = displayedDurationFloorMs.get(key);
+  const next = previous === undefined ? durationMs : Math.max(previous, durationMs);
   if (next !== previous) displayedDurationFloorMs.set(key, next);
   return next;
 }
@@ -296,21 +281,12 @@ function sealedDisplayDurationMs(message: ChatMessage, durationMs: number | null
   const sealedFloor = sealedDurationMs.get(key);
   const previous = maxDefinedDurationMs(runningFloor, sealedFloor);
   displayedDurationFloorMs.delete(key);
-  visibleTimingSamples.delete(key);
   if (durationMs === null) return previous ?? null;
   const next = previous === null ? durationMs : Math.max(previous, durationMs);
   if (next !== previous) sealedDurationMs.set(key, next);
   return next;
 }
 
-function smoothVisibleIncreasingDurationMs(previous: number | undefined, previousObservedAtMs: number | undefined, targetMs: number, observedAtMs: number): number {
-  const target = Math.max(0, Math.trunc(targetMs));
-  if (previous === undefined || !Number.isFinite(previous)) return target;
-  const elapsedSincePreviousSample = Number.isFinite(previousObservedAtMs) ? Math.max(0, observedAtMs - Number(previousObservedAtMs)) : 0;
-  const visibleCeiling = previous + elapsedSincePreviousSample;
-  return Math.max(previous, Math.min(target, Math.trunc(visibleCeiling)));
-}
-
 function maxDefinedDurationMs(...values: Array<number | undefined>): number | null {
   let maximum: number | null = null;
   for (const value of values) {
@@ -343,34 +319,12 @@ function migrateVisibleTimingAliases(primary: string, aliases: unknown[]): void
 function messageActivityMeta(message: ChatMessage): { text: string; label: string } | null {
   if (!isRunningMessage(message)) return null;
   const timing = messageTimingForDisplay(message);
-  const ageMs = visibleLastEventAgeMs(message, timing?.lastEventAt);
+  const ageMs = durationSince(timing?.lastEventAt);
   if (ageMs === null) return null;
   const value = formatDuration(ageMs) + "前";
   return { text: `最近 ${value}`, label: `最近事件：${value}` };
 }
 
-function visibleLastEventAgeMs(message: ChatMessage, timestamp: unknown): number | null {
-  const eventAtMs = timestampMs(timestamp);
-  if (eventAtMs === null) return null;
-  const key = messageDurationFloorKey(message);
-  const sample = visibleTimingSamples.get(key) ?? {};
-  const now = nowMs.value;
-  const targetAgeMs = Math.max(0, now - eventAtMs);
-  let nextAgeMs: number;
-  if (sample.lastEventAgeMs === undefined || !Number.isFinite(sample.lastEventAgeMs)) {
-    nextAgeMs = targetAgeMs;
-  } else if (sample.lastEventSourceMs !== undefined && eventAtMs > sample.lastEventSourceMs) {
-    nextAgeMs = 0;
-  } else {
-    nextAgeMs = smoothVisibleIncreasingDurationMs(sample.lastEventAgeMs, sample.lastEventObservedAtMs, targetAgeMs, now);
-  }
-  sample.lastEventAgeMs = nextAgeMs;
-  sample.lastEventObservedAtMs = now;
-  sample.lastEventSourceMs = eventAtMs;
-  visibleTimingSamples.set(key, sample);
-  return nextAgeMs;
-}
-
 function messageTimingForDisplay(message: ChatMessage): ChatMessage["timing"] {
   // The main message card consumes only the durable message timing projection.
   // Trace timing belongs to TraceTimeline/details; letting trace hydration drive the
diff --git a/web/hwlab-cloud-web/src/composables/useWorkbenchNowTicker.ts b/web/hwlab-cloud-web/src/composables/useWorkbenchNowTicker.ts
index a635a92d..f8e7a93d 100644
--- a/web/hwlab-cloud-web/src/composables/useWorkbenchNowTicker.ts
+++ b/web/hwlab-cloud-web/src/composables/useWorkbenchNowTicker.ts
@@ -4,7 +4,6 @@
 import { onBeforeUnmount, readonly, ref, watch, type Ref } from "vue";
 
 const TICK_INTERVAL_MS = 1000;
-const MAX_VISIBLE_TICK_STEP_MS = TICK_INTERVAL_MS;
 
 const nowMs = ref(Date.now());
 const activeSubscribers = new Map<symbol, boolean>();
@@ -31,18 +30,8 @@ export function useWorkbenchNowTicker(enabled: Ref<boolean>) {
   return { nowMs: readonly(nowMs), refreshNow };
 }
 
-function refreshNow(reset = false): void {
-  const wallNow = Date.now();
-  if (reset) {
-    nowMs.value = wallNow;
-    return;
-  }
-  const previous = Number(nowMs.value);
-  if (!Number.isFinite(previous) || wallNow <= previous) {
-    nowMs.value = wallNow;
-    return;
-  }
-  nowMs.value = Math.min(wallNow, previous + MAX_VISIBLE_TICK_STEP_MS);
+function refreshNow(): void {
+  nowMs.value = Date.now();
 }
 
 function reconcileTimer(): void {
@@ -51,7 +40,7 @@ function reconcileTimer(): void {
   // elapsed/recent labels advance monotonically instead of jumping on resume.
   const shouldRun = isBrowser() && hasActiveSubscriber();
   if (shouldRun && timer === null) {
-    refreshNow(true);
+    refreshNow();
     timer = window.setInterval(refreshNow, TICK_INTERVAL_MS);
     return;
   }