diff --git a/internal/web/ui/templates/devices.html b/internal/web/ui/templates/devices.html
index 704ef07..3c88644 100644
--- a/internal/web/ui/templates/devices.html
+++ b/internal/web/ui/templates/devices.html
@@ -47,10 +47,7 @@
         {{if $allOffline}}
         <button type="submit" id="cleanup-btn" name="action" value="cleanup_offline" class="danger" style="display:none" onclick="var n=document.querySelectorAll('input[name=device_id]:checked').length;return confirm('确认清理选中的 '+n+' 台离线设备及其全部关联数据？此操作不可恢复。')">清理选中离线设备</button>
         {{end}}
-        {{$drift := false}}{{range .DeviceRows}}{{if and (gt .TimeDriftSec $.TimeSyncThreshold) (hasString $.SelectedDeviceIDs .Device.DeviceID)}}{{$drift = true}}{{end}}{{end}}
-        {{if $drift}}
-        <button type="submit" name="action" value="time_sync" class="secondary">⏱ 时间同步</button>
-        {{end}}
+        <button type="submit" id="time-sync-btn" name="action" value="time_sync" class="secondary" style="display:none">⏱ 时间同步</button>
         <a class="btn secondary" href="{{.BatchConfigURL}}">下发设备分配</a>
         <a class="btn secondary" href="/devices">清空选择</a>
       </div>
@@ -178,6 +175,19 @@
       });
       cleanupBtn.style.display = allOffline ? '' : 'none';
     }
+    // Show/hide time sync button if any selected device has time drift
+    const syncBtn = document.getElementById('time-sync-btn');
+    if (syncBtn) {
+      let hasDrift = false;
+      checked.forEach(cb => {
+        const row = cb.closest('tr');
+        if (row) {
+          const driftEl = row.querySelector('.pill.bad');
+          if (driftEl && driftEl.textContent.includes('偏差')) hasDrift = true;
+        }
+      });
+      syncBtn.style.display = hasDrift ? '' : 'none';
+    }
   };
   for (const box of selectedBoxes) {
     box.addEventListener('change', syncSelected);
diff --git a/safesightd.json b/safesightd.json
index 8c21f99..2146aa1 100644
--- a/safesightd.json
+++ b/safesightd.json
@@ -8,8 +8,10 @@
   "data_dir": "data",
   "db_path": "data/app.db",
   "log_dir": "data/logs",
+  "alarm_retention_days": 30,
+  "company_name": "金航数码有限公司",
+  "time_sync_threshold_sec": 10,
   "device_aliases": {
     "d12a4719c91641df91b76ab271280797": "盒子A"
-  },
-  "alarm_retention_days": 30
-}
+  }
+}
\ No newline at end of file