diff --git a/core/frontend/src/app.component.html b/core/frontend/src/app.component.html
index c4b3320..3dfc334 100644
--- a/core/frontend/src/app.component.html
+++ b/core/frontend/src/app.component.html
@@ -21,7 +21,7 @@
     <!-- 第一行：站点编号 / 地图类型 / 预报源 / 图例 -->
     <div class="flex flex-wrap items-center gap-3 mb-3">
       <label class="text-sm text-gray-600">站点编号</label>
-      <input class="px-2 py-1 border rounded w-32 font-mono text-sm" [(ngModel)]="decimalId" placeholder="十进制ID" />
+      <input class="px-2 py-1 border rounded w-32 font-mono text-sm" [(ngModel)]="decimalId" placeholder="十六进制（如 29CA）" />
 
       <label class="text-sm text-gray-600">地图类型</label>
       <select class="px-2 py-1 border rounded text-sm" [(ngModel)]="mapType" (change)="switchLayer(mapType)">
diff --git a/core/frontend/src/app/api.service.ts b/core/frontend/src/app/api.service.ts
index 5a6fb8f..6d0a979 100644
--- a/core/frontend/src/app/api.service.ts
+++ b/core/frontend/src/app/api.service.ts
@@ -30,8 +30,8 @@ export class ApiService {
     try { const r = await fetch('/api/stations'); return await r.json(); } catch { return []; }
   }
 
-  async getHistory(decimalId: string, from: string, to: string, interval: string): Promise<WeatherPoint[]> {
-    const params = new URLSearchParams({ decimal_id: decimalId, start_time: from, end_time: to, interval });
+  async getHistory(hexId: string, from: string, to: string, interval: string): Promise<WeatherPoint[]> {
+    const params = new URLSearchParams({ hex_id: hexId, start_time: from, end_time: to, interval });
     const r = await fetch(`/api/data?${params.toString()}`);
     if (!r.ok) return [];
     return await r.json();
@@ -44,4 +44,3 @@ export class ApiService {
     return await r.json();
   }
 }
-
diff --git a/core/frontend/src/app/header.component.html b/core/frontend/src/app/header.component.html
index d4d421a..af160b6 100644
--- a/core/frontend/src/app/header.component.html
+++ b/core/frontend/src/app/header.component.html
@@ -7,11 +7,10 @@
     <div class="device-list" style="flex:1;overflow:auto;">
       <button class="device-item" *ngFor="let s of pageItems" (click)="choose(s)" style="padding:10px 16px;border-bottom:1px solid #f5f5f5;display:flex;justify-content:space-between;align-items:center;width:100%;text-align:left;">
         <div>
-          <div class="text-sm font-mono">{{s.station_id}}</div>
-          <div class="text-xs text-gray-500">十进制: {{decId(s)}}</div>
-          <div class="text-xs text-gray-500" *ngIf="s.location">位置: {{s.location}}</div>
+          <div class="text-sm" *ngIf="s.location">{{s.location}}</div>
+          <div class="text-xs text-gray-500">设备编号：{{s.station_id}}</div>
         </div>
-        <div class="text-xs text-gray-600">{{s.device_type}}</div>
+        <div class="text-xs" [class.text-green-600]="isOnline(s)" [class.text-gray-500]="!isOnline(s)">{{ isOnline(s) ? '在线' : '离线' }}</div>
       </button>
     </div>
     <div class="device-list-footer" style="padding:10px;border-top:1px solid #eee;display:flex;justify-content:space-between;align-items:center;">
diff --git a/core/frontend/src/app/header.component.ts b/core/frontend/src/app/header.component.ts
index 451ce2c..36a3269 100644
--- a/core/frontend/src/app/header.component.ts
+++ b/core/frontend/src/app/header.component.ts
@@ -1,7 +1,7 @@
 import { Component, EventEmitter, Input, Output } from '@angular/core';
 import { CommonModule } from '@angular/common';
 
-type Station = { station_id: string; device_type?: string; name?: string; station_alias?: string; location?: string };
+type Station = { station_id: string; device_type?: string; name?: string; station_alias?: string; location?: string; last_update?: string };
 
 @Component({
   selector: 'app-header',
@@ -12,7 +12,7 @@ type Station = { station_id: string; device_type?: string; name?: string; statio
 export class HeaderComponent {
   @Input() onlineDevices = 0;
   @Input() stations: Station[] = [];
-  @Output() selectStation = new EventEmitter<{ stationId: string, decimalId: string }>();
+  @Output() selectStation = new EventEmitter<{ stationId: string, hex: string }>();
 
   modalOpen = false;
   currentPage = 1;
@@ -30,17 +30,23 @@ export class HeaderComponent {
   prev() { if (this.currentPage > 1) this.currentPage--; }
   next() { if (this.currentPage < this.totalPages) this.currentPage++; }
 
-  decId(s: Station): string {
+  hexSuffix(s: Station): string {
     const id = s.station_id || '';
-    if (id.length <= 6) return '';
-    const hex = id.slice(-6);
-    const n = parseInt(hex, 16);
-    return isNaN(n) ? '' : String(n);
+    if (id.length <= 6) return id.toUpperCase();
+    return id.slice(-6).toUpperCase();
+  }
+
+  isOnline(s: Station): boolean {
+    const lu = (s as any).last_update as string | undefined;
+    if (!lu) return false;
+    const t = new Date(lu.replace(' ', 'T')).getTime();
+    if (isNaN(t)) return false;
+    return Date.now() - t <= 5 * 60 * 1000;
   }
 
   choose(s: Station) {
-    const dec = this.decId(s);
-    if (dec) this.selectStation.emit({ stationId: s.station_id, decimalId: dec });
+    const hex = this.hexSuffix(s);
+    if (hex) this.selectStation.emit({ stationId: s.station_id, hex });
     this.close();
   }
 }
diff --git a/core/frontend/src/main.ts b/core/frontend/src/main.ts
index 040607a..4b81764 100644
--- a/core/frontend/src/main.ts
+++ b/core/frontend/src/main.ts
@@ -190,9 +190,15 @@ export class AppComponent implements OnInit, AfterViewInit {
           image: new ol.style.Circle({ radius, fill: new ol.style.Fill({ color: 'rgba(0,123,255,0.8)' }), stroke: new ol.style.Stroke({ color: '#fff', width: 2 }) }),
           text: new ol.style.Text({ text: String(size), fill: new ol.style.Fill({ color: '#fff' }), font: `bold ${fontSize}px Arial`, offsetY: 1 })
         });
+      } else {
+        const f0 = features[0];
+        const last = f0?.get('lastUpdate');
+        const online = last ? (new Date(last).getTime() > Date.now() - 5*60*1000) : false;
+        const color = online ? 'rgba(0,123,255,0.8)' : 'rgba(108,117,125,0.8)';
+        return new ol.style.Style({
+          image: new ol.style.Circle({ radius: 6, fill: new ol.style.Fill({ color }), stroke: new ol.style.Stroke({ color: '#fff', width: 2 }) })
+        });
       }
-      const f0 = features[0];
-      return this.createStationStyle(f0);
     }
     return this.createStationStyle(features[0]);
   }
@@ -214,17 +220,21 @@ export class AppComponent implements OnInit, AfterViewInit {
         let f = features[0];
         const subs = f.get('features');
         if (subs && subs.length>0) {
-          // zoom in on cluster instead of selecting
           const view = this.map.getView();
-          const z = view.getZoom();
-          view.animate({ zoom: z + 1, center: evt.coordinate, duration: 200 });
+          const ex = olAny.extent.createEmpty();
+          for (const sf of subs) {
+            olAny.extent.extend(ex, sf.getGeometry().getExtent());
+          }
+          view.fit(ex, { duration: 300, maxZoom: 14, padding: [40,40,40,40] });
           return;
         }
         const sid = f.get('stationId');
         const loc = f.get('location') || '';
         if (!sid) return;
-        const hex = String(sid).slice(-6); const dec = parseInt(hex, 16);
-        if (!isNaN(dec)) { this.decimalId = String(dec); await this.query(); this.scrollToChart(); }
+        const hex = String(sid).slice(-6).toUpperCase();
+        this.decimalId = hex;
+        await this.query();
+        this.scrollToChart();
       });
       this.map.on('pointermove', (evt:any) => {
         const features = this.map.getFeaturesAtPixel(evt.pixel, { layerFilter: (l:any)=> l===this.stationLayer || l===this.clusterLayer });
@@ -319,17 +329,17 @@ export class AppComponent implements OnInit, AfterViewInit {
     await this.loadTileTimes(this.tileProduct);
   }
 
-  private makeStationId(dec: string): string | null {
-    const n = Number(dec);
-    if (!isFinite(n)) return null;
-    const hex = Math.trunc(n).toString(16).toUpperCase().padStart(6,'0');
+  private makeStationIdFromHex(hexRaw: string): string | null {
+    if (!hexRaw) return null;
+    const hex = String(hexRaw).toUpperCase().replace(/[^0-9A-F]/g, '').padStart(6, '0').slice(-6);
+    if (!hex) return null;
     return `RS485-${hex}`;
   }
 
   async query() {
     const dec = this.decimalId.trim();
     if (!dec) return;
-    const sid = this.makeStationId(dec);
+    const sid = this.makeStationIdFromHex(dec);
     if (!sid) return;
     const toFmt = (s: string) => s.replace('T',' ') + ':00';
     const from = toFmt(this.start);
@@ -357,8 +367,8 @@ export class AppComponent implements OnInit, AfterViewInit {
     this.scrollToChart();
   }
 
-  onSelectStation(ev: { stationId: string, decimalId: string }) {
-    this.decimalId = ev.decimalId;
+  onSelectStation(ev: { stationId: string, hex: string }) {
+    this.decimalId = ev.hex;
     this.query();
   }
 
diff --git a/core/internal/server/handlers.go b/core/internal/server/handlers.go
index e3a835f..3c34986 100644
--- a/core/internal/server/handlers.go
+++ b/core/internal/server/handlers.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/http"
 	"strconv"
+	"strings"
 	"time"
 	"weatherstation/core/internal/data"
 )
@@ -40,18 +41,34 @@ func handleStations(c *gin.Context) {
 }
 
 func handleData(c *gin.Context) {
-	dec := c.Query("decimal_id")
+	idParam := c.Query("hex_id")
 	startTime := c.Query("start_time")
 	endTime := c.Query("end_time")
 	interval := c.DefaultQuery("interval", "1hour")
 
-	decimalNum, err := strconv.ParseInt(dec, 10, 64)
-	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid decimal_id"})
+	if idParam == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "missing hex_id"})
 		return
 	}
-	hexID := fmt.Sprintf("%06X", decimalNum)
-	stationID := fmt.Sprintf("RS485-%s", hexID)
+	upper := strings.ToUpper(idParam)
+	var b strings.Builder
+	for i := 0; i < len(upper); i++ {
+		ch := upper[i]
+		if (ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'F') {
+			b.WriteByte(ch)
+		}
+	}
+	hex := b.String()
+	if hex == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid hex_id"})
+		return
+	}
+	if len(hex) < 6 {
+		hex = strings.Repeat("0", 6-len(hex)) + hex
+	} else if len(hex) > 6 {
+		hex = hex[len(hex)-6:]
+	}
+	stationID := fmt.Sprintf("RS485-%s", hex)
 
 	loc, _ := time.LoadLocation("Asia/Shanghai")
 	if loc == nil {