From 46144ef63a7f79ffb2b9c8922f1194df8ed17d3d Mon Sep 17 00:00:00 2001
From: t <tczk@tdeMacBook-Pro.local>
Date: Sun, 30 Aug 2026 12:29:22 +0800
Subject: [PATCH] fix(support-chat): support legacy mobile browsers

---
 internal/bootstrap/init.go                 |   8 +
 internal/builders/conversation_builder.go  |   4 +-
 internal/services/public_asset_url.go      |  75 +++++++++
 internal/services/public_asset_url_test.go |  42 +++++
 internal/services/ws_service.go            |   4 +-
 internal/web/supportchat/assets/chat.css   |  41 ++---
 internal/web/supportchat/assets/chat.js    | 180 ++++++++++++---------
 internal/web/supportchat/handler_test.go   |  49 ++++++
 8 files changed, 302 insertions(+), 101 deletions(-)
 create mode 100644 internal/services/public_asset_url.go
 create mode 100644 internal/services/public_asset_url_test.go

diff --git a/internal/bootstrap/init.go b/internal/bootstrap/init.go
index 1c32ffd..5a74ff1 100644
--- a/internal/bootstrap/init.go
+++ b/internal/bootstrap/init.go
@@ -8,6 +8,7 @@ import (
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/config"
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/i18nx"
 	"code.tczkiot.com/wlw/ai-agent/internal/pkg/logx"
+	"code.tczkiot.com/wlw/ai-agent/internal/services"
 	"code.tczkiot.com/wlw/ai-agent/internal/services/cronx"
 	_ "code.tczkiot.com/wlw/ai-agent/internal/services/event_handlers"
 	"code.tczkiot.com/wlw/ai-agent/internal/wxwork"
@@ -31,6 +32,13 @@ func InitModule(database *gorm.DB, tablePrefix string, loadSettings LoadSettings
 	}
 	config.SetCurrent(cfg)
 	i18nx.SetDefaultLocale(cfg.LanguageOrDefault())
+	assetSettings, assetErr := loadSettings(context.Background(), "oss_")
+	if assetErr != nil {
+		slog.Warn("load host asset settings failed", "error", assetErr)
+		services.SetPublicAssetURLResolver(nil)
+	} else {
+		services.SetPublicAssetURLSettings(assetSettings)
+	}
 
 	if err := UseDatabase(database, tablePrefix); err != nil {
 		return err
diff --git a/internal/builders/conversation_builder.go b/internal/builders/conversation_builder.go
index d9fc69a..eacd7b0 100644
--- a/internal/builders/conversation_builder.go
+++ b/internal/builders/conversation_builder.go
@@ -187,7 +187,7 @@ func BuildMessageWithReadStatesAndLocale(item *models.Message, agentReadState, c
 			}
 			if aiAgent != nil {
 				ret.SenderName = aiAgent.Name
-				ret.SenderAvatar = strings.TrimSpace(aiAgent.Avatar)
+				ret.SenderAvatar = services.ResolvePublicAssetURL(aiAgent.Avatar)
 			}
 		} else if item.SenderType == enums.IMSenderTypeAgent {
 			profile := agentProfiles[item.SenderID]
@@ -196,7 +196,7 @@ func BuildMessageWithReadStatesAndLocale(item *models.Message, agentReadState, c
 					ret.SenderName = dn
 				}
 				if av := strings.TrimSpace(profile.Avatar); av != "" {
-					ret.SenderAvatar = av
+					ret.SenderAvatar = services.ResolvePublicAssetURL(av)
 				}
 			}
 			if ret.SenderName == "" {
diff --git a/internal/services/public_asset_url.go b/internal/services/public_asset_url.go
new file mode 100644
index 0000000..683e146
--- /dev/null
+++ b/internal/services/public_asset_url.go
@@ -0,0 +1,75 @@
+package services
+
+import (
+	"strings"
+	"sync"
+)
+
+var publicAssetURLRuntime struct {
+	sync.RWMutex
+	resolver func(string) string
+}
+
+// SetPublicAssetURLResolver configures how host-owned asset keys are exposed
+// to standalone customer-service clients. A nil resolver keeps absolute URLs
+// and legacy values unchanged.
+func SetPublicAssetURLResolver(resolver func(string) string) {
+	publicAssetURLRuntime.Lock()
+	publicAssetURLRuntime.resolver = resolver
+	publicAssetURLRuntime.Unlock()
+}
+
+// SetPublicAssetURLSettings applies the same object-key joining rule used by
+// the management frontend: cloud material keys use the active oss_domain,
+// while absolute and same-origin URLs stay unchanged.
+func SetPublicAssetURLSettings(settings map[string]string) {
+	engine := strings.TrimSpace(settings["oss_default_engine"])
+	if engine == "" || engine == "local" {
+		SetPublicAssetURLResolver(nil)
+		return
+	}
+	domain := strings.TrimSpace(settings["oss_"+engine+"_domain"])
+	SetPublicAssetURLResolver(func(value string) string {
+		return resolvePublicAssetURLWithDomain(value, domain)
+	})
+}
+
+func resolvePublicAssetURLWithDomain(value, domain string) string {
+	value = strings.TrimSpace(value)
+	if value == "" || strings.HasPrefix(value, "/") {
+		return value
+	}
+	lower := strings.ToLower(value)
+	if strings.HasPrefix(lower, "http://") || strings.HasPrefix(lower, "https://") || strings.HasPrefix(lower, "data:") {
+		return value
+	}
+	domain = strings.TrimSpace(domain)
+	if domain == "" {
+		return value
+	}
+	if !strings.HasPrefix(strings.ToLower(domain), "http://") && !strings.HasPrefix(strings.ToLower(domain), "https://") {
+		domain = "https://" + domain
+	}
+	return strings.TrimRight(domain, "/") + "/" + strings.TrimLeft(value, "/")
+}
+
+// ResolvePublicAssetURL converts a host-owned object key into a browser-ready
+// URL. Resolver failures must fall back to the stored value so message delivery
+// is never affected by an optional avatar.
+func ResolvePublicAssetURL(value string) string {
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return value
+	}
+	publicAssetURLRuntime.RLock()
+	resolver := publicAssetURLRuntime.resolver
+	publicAssetURLRuntime.RUnlock()
+	if resolver == nil {
+		return value
+	}
+	resolved := strings.TrimSpace(resolver(value))
+	if resolved == "" {
+		return value
+	}
+	return resolved
+}
diff --git a/internal/services/public_asset_url_test.go b/internal/services/public_asset_url_test.go
new file mode 100644
index 0000000..4050b45
--- /dev/null
+++ b/internal/services/public_asset_url_test.go
@@ -0,0 +1,42 @@
+package services
+
+import "testing"
+
+func TestResolvePublicAssetURL(t *testing.T) {
+	SetPublicAssetURLResolver(func(value string) string {
+		return "https://cdn.example.com/" + value
+	})
+	t.Cleanup(func() { SetPublicAssetURLResolver(nil) })
+
+	if got := ResolvePublicAssetURL(" mall/materials/avatar.png "); got != "https://cdn.example.com/mall/materials/avatar.png" {
+		t.Fatalf("ResolvePublicAssetURL() = %q", got)
+	}
+}
+
+func TestResolvePublicAssetURLFallsBackToStoredValue(t *testing.T) {
+	SetPublicAssetURLResolver(func(string) string { return "" })
+	t.Cleanup(func() { SetPublicAssetURLResolver(nil) })
+
+	if got := ResolvePublicAssetURL(" /storage/avatar.png "); got != "/storage/avatar.png" {
+		t.Fatalf("ResolvePublicAssetURL() = %q", got)
+	}
+}
+
+func TestSetPublicAssetURLSettingsUsesManagementDomainRule(t *testing.T) {
+	SetPublicAssetURLSettings(map[string]string{
+		"oss_default_engine": "qiniu",
+		"oss_qiniu_domain":   "cdn.example.com",
+	})
+	t.Cleanup(func() { SetPublicAssetURLResolver(nil) })
+
+	tests := map[string]string{
+		"mall/materials/avatar.png":           "https://cdn.example.com/mall/materials/avatar.png",
+		"/storage/builtin-avatar.png":         "/storage/builtin-avatar.png",
+		"https://system.example.com/icon.png": "https://system.example.com/icon.png",
+	}
+	for input, want := range tests {
+		if got := ResolvePublicAssetURL(input); got != want {
+			t.Fatalf("ResolvePublicAssetURL(%q) = %q, want %q", input, got, want)
+		}
+	}
+}
diff --git a/internal/services/ws_service.go b/internal/services/ws_service.go
index e4601a1..2992e52 100644
--- a/internal/services/ws_service.go
+++ b/internal/services/ws_service.go
@@ -364,7 +364,7 @@ func (s *wsService) fillRealtimeMessageSender(ret *response.MessageResponse, ite
 	case enums.IMSenderTypeAI:
 		if aiAgent := AIAgentService.Get(item.SenderID); aiAgent != nil {
 			ret.SenderName = aiAgent.Name
-			ret.SenderAvatar = strings.TrimSpace(aiAgent.Avatar)
+			ret.SenderAvatar = ResolvePublicAssetURL(aiAgent.Avatar)
 		}
 	case enums.IMSenderTypeAgent:
 		if profile := AgentProfileService.GetByUserID(item.SenderID); profile != nil {
@@ -372,7 +372,7 @@ func (s *wsService) fillRealtimeMessageSender(ret *response.MessageResponse, ite
 				ret.SenderName = displayName
 			}
 			if avatar := strings.TrimSpace(profile.Avatar); avatar != "" {
-				ret.SenderAvatar = avatar
+				ret.SenderAvatar = ResolvePublicAssetURL(avatar)
 			}
 		}
 		if ret.SenderName == "" {
diff --git a/internal/web/supportchat/assets/chat.css b/internal/web/supportchat/assets/chat.css
index 8397d08..6eb1af4 100644
--- a/internal/web/supportchat/assets/chat.css
+++ b/internal/web/supportchat/assets/chat.css
@@ -18,6 +18,7 @@
 html, body { width: 100%; height: 100%; margin: 0; }
 body { min-width: 320px; overflow: hidden; background: var(--muted); }
 button, textarea, input { font: inherit; }
+button, textarea { -webkit-appearance: none; appearance: none; }
 button { color: inherit; }
 button:focus-visible, textarea:focus-visible { outline: 3px solid rgba(var(--theme-rgb), .2); outline-offset: 2px; }
 [hidden] { display: none !important; }
@@ -28,8 +29,8 @@ svg { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round
 .chat-shell { position: relative; display: flex; flex-direction: column; color: var(--foreground); background: var(--card); }
 
 .chat-header { z-index: 5; min-height: 68px; padding: 10px 12px 10px 16px; display: flex; align-items: center; gap: 12px; flex: 0 0 auto; border-bottom: 1px solid rgba(226, 232, 240, .76); background: rgba(255, 255, 255, .88); box-shadow: 0 8px 28px rgba(15, 23, 42, .035); backdrop-filter: blur(20px) saturate(1.35); }
-.brand-mark { position: relative; width: 42px; height: 42px; display: inline-flex; align-items: center; justify-content: center; flex: 0 0 auto; border: 1px solid rgba(255, 255, 255, .65); border-radius: 14px; color: #fff; background: linear-gradient(145deg, color-mix(in srgb, var(--theme), #fff 14%), color-mix(in srgb, var(--theme), #6d5dfc 30%)); box-shadow: 0 10px 24px rgba(var(--theme-rgb), .24), inset 0 1px 0 rgba(255,255,255,.28); }
-.brand-mark::before { content: ""; position: absolute; inset: -5px; z-index: -1; border-radius: 17px; background: rgba(var(--theme-rgb), .08); }
+.brand-mark { position: relative; width: 42px; height: 42px; display: inline-flex; align-items: center; justify-content: center; flex: 0 0 auto; border: 1px solid rgba(255, 255, 255, .65); border-radius: 14px; color: #fff; background: linear-gradient(145deg, #4f8bfc, #456eea); background: linear-gradient(145deg, color-mix(in srgb, var(--theme), #fff 14%), color-mix(in srgb, var(--theme), #6d5dfc 30%)); box-shadow: 0 10px 24px rgba(var(--theme-rgb), .24), inset 0 1px 0 rgba(255,255,255,.28); }
+.brand-mark::before { content: ""; position: absolute; top: -5px; right: -5px; bottom: -5px; left: -5px; inset: -5px; z-index: -1; border-radius: 17px; background: rgba(var(--theme-rgb), .08); }
 .brand-mark svg { width: 20px; height: 20px; stroke-width: 1.9; }
 .header-status-dot { position: absolute; right: -3px; bottom: -3px; width: 12px; height: 12px; border: 3px solid var(--card); border-radius: 50%; background: #94a3b8; }
 .header-status-dot.connected { background: #10b981; box-shadow: 0 0 0 2px rgba(16,185,129,.14); }
@@ -50,7 +51,7 @@ svg { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round
 .icon-button svg { width: 16px; height: 16px; }
 .chat-header .icon-button { border: 1px solid rgba(226,232,240,.86); background: rgba(248,250,252,.76); box-shadow: 0 2px 8px rgba(15,23,42,.045), inset 0 1px 0 rgba(255,255,255,.8); backdrop-filter: blur(10px); }
 .chat-header .icon-button svg { width: 16px; height: 16px; stroke-width: 1.9; transition: transform .22s cubic-bezier(.2,.8,.2,1); }
-#retry-button { color: color-mix(in srgb, var(--theme), #475467 32%); border-color: rgba(var(--theme-rgb), .12); background: rgba(var(--theme-rgb), .055); }
+#retry-button { color: #326fd1; color: color-mix(in srgb, var(--theme), #475467 32%); border-color: rgba(var(--theme-rgb), .12); background: rgba(var(--theme-rgb), .055); }
 #retry-button:hover { color: var(--theme); border-color: rgba(var(--theme-rgb), .2); background: rgba(var(--theme-rgb), .1); box-shadow: 0 7px 18px rgba(var(--theme-rgb), .12); }
 #retry-button:hover svg { transform: rotate(45deg); }
 #retry-button:active svg { transform: rotate(120deg); transition-duration: .1s; }
@@ -59,7 +60,7 @@ svg { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round
 .close-button:hover svg { transform: scale(.88); }
 
 .chat-content { position: relative; min-height: 0; flex: 1; display: grid; grid-template-rows: minmax(0, 1fr) auto; overflow: hidden; background: linear-gradient(180deg, #f8faff 0%, #f5f8fd 55%, #f2f6fb 100%); }
-.chat-content::before { content: ""; position: absolute; inset: 0; pointer-events: none; background: radial-gradient(circle at 6% 8%, rgba(var(--theme-rgb), .075), transparent 30%), radial-gradient(circle at 96% 42%, rgba(124, 93, 252, .055), transparent 28%); }
+.chat-content::before { content: ""; position: absolute; top: 0; right: 0; bottom: 0; left: 0; inset: 0; pointer-events: none; background: radial-gradient(circle at 6% 8%, rgba(var(--theme-rgb), .075), transparent 30%), radial-gradient(circle at 96% 42%, rgba(124, 93, 252, .055), transparent 28%); }
 .message-scroller { position: relative; z-index: 1; min-height: 0; overflow-x: hidden; overflow-y: auto; padding: 20px 18px 24px; overscroll-behavior: contain; scroll-behavior: smooth; background: transparent; scrollbar-width: thin; scrollbar-color: var(--border) transparent; }
 .message-scroller::-webkit-scrollbar { width: 10px; }
 .message-scroller::-webkit-scrollbar-thumb { border: 2px solid transparent; border-radius: 999px; background: var(--border); background-clip: padding-box; }
@@ -75,16 +76,16 @@ svg { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round
 .message-row { width: 100%; min-width: 0; display: flex; align-items: flex-start; gap: 10px; font-size: 14px; }
 .message-row.mine { flex-direction: row-reverse; }
 .message-row.system { justify-content: center; }
-.message-avatar { width: 34px; height: 34px; display: inline-flex; align-items: center; justify-content: center; flex: 0 0 auto; overflow: hidden; border: 2px solid rgba(255,255,255,.92); border-radius: 12px; color: var(--theme); background: color-mix(in srgb, var(--theme), #fff 91%); box-shadow: 0 5px 16px rgba(15,23,42,.07); font-size: 11px; font-weight: 650; }
+.message-avatar { width: 34px; height: 34px; display: inline-flex; align-items: center; justify-content: center; flex: 0 0 auto; overflow: hidden; border: 2px solid rgba(255,255,255,.92); border-radius: 12px; color: var(--theme); background: #eaf2ff; background: color-mix(in srgb, var(--theme), #fff 91%); box-shadow: 0 5px 16px rgba(15,23,42,.07); font-size: 11px; font-weight: 650; }
 .message-avatar img { width: 100%; height: 100%; object-fit: cover; }
-.message-copy { min-width: 0; max-width: 84%; display: flex; flex-direction: column; gap: 6px; align-items: flex-start; overflow-wrap: anywhere; }
+.message-copy { min-width: 0; max-width: 84%; display: flex; flex-direction: column; gap: 6px; align-items: flex-start; word-break: break-word; overflow-wrap: anywhere; }
 .message-row.mine .message-copy { align-items: flex-end; }
 .message-row.system .message-copy { max-width: 85%; align-items: center; }
 .message-meta { padding: 0 5px; display: flex; flex-wrap: wrap; align-items: center; gap: 4px 7px; color: #7b8496; font-size: 10px; line-height: 15px; }
 .message-row.mine .message-meta { justify-content: flex-end; text-align: right; }
 .message-sender { color: #596579; font-weight: 600; }
-.message-bubble { width: fit-content; max-width: 100%; min-width: 0; padding: 10px 14px; overflow: hidden; border: 1px solid rgba(225,232,242,.78); border-radius: 18px 18px 18px 6px; color: var(--foreground); background: rgba(255,255,255,.93); box-shadow: 0 10px 30px rgba(15,23,42,.065), inset 0 1px 0 rgba(255,255,255,.8); font-size: 14px; line-height: 1.55; overflow-wrap: anywhere; }
-.message-row.mine .message-bubble { border-color: transparent; border-radius: 18px 18px 6px 18px; color: #fff; background: linear-gradient(135deg, color-mix(in srgb, var(--theme), #fff 6%), color-mix(in srgb, var(--theme), #7c5dfc 24%)); box-shadow: 0 12px 28px rgba(var(--theme-rgb), .22); }
+.message-bubble { width: fit-content; max-width: 100%; min-width: 0; padding: 10px 14px; overflow: hidden; border: 1px solid rgba(225,232,242,.78); border-radius: 18px 18px 18px 6px; color: var(--foreground); background: rgba(255,255,255,.93); box-shadow: 0 10px 30px rgba(15,23,42,.065), inset 0 1px 0 rgba(255,255,255,.8); font-size: 14px; line-height: 1.55; word-break: break-word; overflow-wrap: anywhere; }
+.message-row.mine .message-bubble { border-color: transparent; border-radius: 18px 18px 6px 18px; color: #fff; background: linear-gradient(135deg, #397ffb, #5368ed); background: linear-gradient(135deg, color-mix(in srgb, var(--theme), #fff 6%), color-mix(in srgb, var(--theme), #7c5dfc 24%)); box-shadow: 0 12px 28px rgba(var(--theme-rgb), .22); }
 .message-row.system .message-bubble { color: var(--muted-foreground); background: var(--muted); box-shadow: none; }
 .message-read { padding: 0 5px; color: var(--muted-foreground); font-size: 10px; }
 .message-bubble p { margin: 0; }
@@ -95,7 +96,7 @@ svg { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round
 .message-bubble pre { max-width: 100%; margin: 8px 0; padding: 8px 10px; overflow-x: auto; border-radius: 8px; background: rgba(15,23,42,.06); white-space: pre-wrap; }
 .message-bubble code { font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace; }
 .message-bubble img { display: block; max-width: 100%; max-height: 320px; border-radius: 12px; cursor: zoom-in; }
-.message-image-grid { width: min(100%, 360px); display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 6px; overflow: hidden; border-radius: 12px; }
+.message-image-grid { width: 100%; max-width: 360px; width: min(100%, 360px); display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 6px; overflow: hidden; border-radius: 12px; }
 .message-image-grid.count-1 { display: block; }
 .message-image-grid img { width: 100%; height: 150px; max-height: none; object-fit: cover; border-radius: 8px; }
 .message-image-grid.count-1 img { width: auto; max-width: 100%; height: auto; max-height: 320px; object-fit: contain; border-radius: 12px; }
@@ -110,25 +111,25 @@ svg { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round
 
 .composer-area { position: relative; z-index: 2; width: 100%; min-width: 0; max-width: 100%; flex: 0 0 auto; overflow: hidden; border-top: 1px solid rgba(226,232,240,.68); background: rgba(255,255,255,.86); box-shadow: 0 -16px 40px rgba(15,23,42,.055); backdrop-filter: blur(20px) saturate(1.2); }
 .queue-status { margin: 10px 12px 2px; padding: 12px; display: flex; align-items: flex-start; gap: 11px; overflow: hidden; border: 1px solid rgba(var(--theme-rgb), .16); border-radius: 16px; background: linear-gradient(135deg, rgba(var(--theme-rgb), .1), rgba(124,93,252,.055)); box-shadow: 0 10px 26px rgba(var(--theme-rgb), .08), inset 0 1px 0 rgba(255,255,255,.64); }
-.queue-status-icon { width: 34px; height: 34px; display: grid; place-items: center; flex: 0 0 auto; border-radius: 11px; color: #fff; background: linear-gradient(145deg, var(--theme), color-mix(in srgb, var(--theme), #7257f5 30%)); box-shadow: 0 8px 18px rgba(var(--theme-rgb), .22); }
+.queue-status-icon { width: 34px; height: 34px; display: grid; place-items: center; flex: 0 0 auto; border-radius: 11px; color: #fff; background: linear-gradient(145deg, #2475fc, #4f62e9); background: linear-gradient(145deg, var(--theme), color-mix(in srgb, var(--theme), #7257f5 30%)); box-shadow: 0 8px 18px rgba(var(--theme-rgb), .22); }
 .queue-status-icon svg { width: 17px; height: 17px; }
 .queue-status-copy { min-width: 0; flex: 1; }
 .queue-status-heading { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
 .queue-status-heading strong { min-width: 0; overflow: hidden; font-size: 13px; font-weight: 680; line-height: 20px; text-overflow: ellipsis; white-space: nowrap; }
 .queue-position { padding: 3px 8px; flex: 0 0 auto; border: 1px solid rgba(var(--theme-rgb), .16); border-radius: 999px; color: var(--theme); background: rgba(255,255,255,.7); font-size: 10px; font-weight: 700; }
 .queue-status p { margin: 3px 0 7px; color: var(--muted-foreground); font-size: 11px; line-height: 17px; }
-.queue-status-meta { display: flex; flex-wrap: wrap; gap: 5px 12px; color: color-mix(in srgb, var(--theme), #475467 42%); font-size: 10px; font-weight: 550; }
+.queue-status-meta { display: flex; flex-wrap: wrap; gap: 5px 12px; color: #496ea6; color: color-mix(in srgb, var(--theme), #475467 42%); font-size: 10px; font-weight: 550; }
 .queue-status-meta span { display: inline-flex; align-items: center; gap: 5px; }
 .queue-status-meta span::before { width: 5px; height: 5px; content: ""; border-radius: 50%; background: currentColor; opacity: .55; }
 .quick-section { padding: 10px 14px 4px; }
-.quick-button { height: 32px; padding: 0 12px; display: inline-flex; align-items: center; gap: 7px; border: 1px solid rgba(var(--theme-rgb), .13); border-radius: 999px; color: color-mix(in srgb, var(--theme), #1f2937 36%); background: rgba(var(--theme-rgb), .065); font-size: 12px; font-weight: 550; cursor: pointer; transition: transform .18s ease, color .18s ease, background .18s ease, box-shadow .18s ease; }
+.quick-button { height: 32px; padding: 0 12px; display: inline-flex; align-items: center; gap: 7px; border: 1px solid rgba(var(--theme-rgb), .13); border-radius: 999px; color: #315f9f; color: color-mix(in srgb, var(--theme), #1f2937 36%); background: rgba(var(--theme-rgb), .065); font-size: 12px; font-weight: 550; cursor: pointer; transition: transform .18s ease, color .18s ease, background .18s ease, box-shadow .18s ease; }
 .quick-button:hover { color: var(--theme); border-color: rgba(var(--theme-rgb), .24); background: rgba(var(--theme-rgb), .1); box-shadow: 0 7px 18px rgba(var(--theme-rgb), .1); transform: translateY(-1px); }
 .quick-button svg { width: 14px; height: 14px; }
-.composer-shell { width: 100%; min-width: 0; max-width: 100%; padding: 8px 12px max(12px, env(safe-area-inset-bottom)); overflow: hidden; }
+.composer-shell { width: 100%; min-width: 0; max-width: 100%; padding: 8px 12px 12px; padding: 8px 12px max(12px, env(safe-area-inset-bottom)); overflow: hidden; }
 .composer { width: 100%; min-width: 0; max-width: 100%; padding: 9px; overflow: hidden; border: 1px solid rgba(218,226,237,.92); border-radius: 18px; background: rgba(255,255,255,.9); box-shadow: 0 12px 34px rgba(15,23,42,.09), inset 0 1px 0 rgba(255,255,255,.9); transition: border-color .18s ease, box-shadow .18s ease, transform .18s ease; }
 .composer:focus-within { border-color: rgba(var(--theme-rgb), .5); box-shadow: 0 0 0 4px rgba(var(--theme-rgb), .08), 0 16px 38px rgba(15,23,42,.1); transform: translateY(-1px); }
 .pending-uploads { width: 100%; min-width: 0; max-width: 100%; margin-bottom: 6px; padding: 2px 8px 4px 2px; display: flex; gap: 8px; overflow-x: auto; overflow-y: hidden; overscroll-behavior-x: contain; scrollbar-width: thin; }
-.pending-upload { width: min(240px, 78%); padding: 7px; display: flex; flex: 0 0 auto; align-items: center; gap: 9px; border: 1px solid rgba(var(--theme-rgb), .14); border-radius: 12px; background: rgba(var(--theme-rgb), .055); }
+.pending-upload { width: 78%; max-width: 240px; width: min(240px, 78%); padding: 7px; display: flex; flex: 0 0 auto; align-items: center; gap: 9px; border: 1px solid rgba(var(--theme-rgb), .14); border-radius: 12px; background: rgba(var(--theme-rgb), .055); }
 .pending-upload-image { position: relative; width: 66px; height: 66px; padding: 0; overflow: visible; border-radius: 12px; background: transparent; }
 .pending-upload-preview { width: 42px; height: 42px; display: grid; place-items: center; flex: 0 0 auto; overflow: hidden; border-radius: 9px; color: var(--theme); background: rgba(var(--theme-rgb), .11); }
 .pending-upload-image .pending-upload-preview { width: 100%; height: 100%; border-radius: 11px; }
@@ -150,14 +151,14 @@ svg { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round
 .attachment-actions { min-width: 0; display: flex; flex: 0 1 auto; align-items: center; gap: 6px; }
 .attachment-actions .icon-button { color: var(--muted-foreground); background: transparent; }
 .send-hint { min-width: 0; margin-left: auto; overflow: hidden; color: var(--muted-foreground); font-size: 10px; text-overflow: ellipsis; white-space: nowrap; }
-.send-button { width: 40px; height: 40px; margin-left: 8px; padding: 0; display: inline-flex; flex: 0 0 40px; align-items: center; justify-content: center; border: 0; border-radius: 13px; color: #fff; background: linear-gradient(145deg, color-mix(in srgb, var(--theme), #fff 8%), color-mix(in srgb, var(--theme), #6d5dfc 25%)); box-shadow: 0 10px 22px rgba(var(--theme-rgb), .28), inset 0 1px 0 rgba(255,255,255,.24); cursor: pointer; transition: filter .18s ease, transform .18s ease, box-shadow .18s ease; }
+.send-button { width: 40px; height: 40px; margin-left: 8px; padding: 0; display: inline-flex; flex: 0 0 40px; align-items: center; justify-content: center; border: 0; border-radius: 13px; color: #fff; background: linear-gradient(145deg, #3c80fb, #4c66ea); background: linear-gradient(145deg, color-mix(in srgb, var(--theme), #fff 8%), color-mix(in srgb, var(--theme), #6d5dfc 25%)); box-shadow: 0 10px 22px rgba(var(--theme-rgb), .28), inset 0 1px 0 rgba(255,255,255,.24); cursor: pointer; transition: filter .18s ease, transform .18s ease, box-shadow .18s ease; }
 .send-button:hover { filter: brightness(1.04); transform: translateY(-1px); box-shadow: 0 13px 28px rgba(var(--theme-rgb), .32); }
 .send-button svg { width: 18px; height: 18px; }
 .send-button:disabled, .quick-button:disabled, .icon-button:disabled { opacity: .45; cursor: not-allowed; }
 .status-bar { padding: 8px 14px; border-top: 1px solid #fecaca; color: #b91c1c; background: #fef2f2; text-align: center; font-size: 12px; }
 
-.dialog-overlay { position: fixed; z-index: 20; inset: 0; display: flex; align-items: center; justify-content: center; padding: 16px; background: rgba(15,23,42,.46); backdrop-filter: blur(8px); animation: fade-in .15s ease-out; }
-.dialog-card { position: relative; width: min(100%, 360px); padding: 24px; border: 1px solid rgba(255,255,255,.72); border-radius: 20px; color: var(--foreground); background: rgba(255,255,255,.96); box-shadow: 0 24px 70px rgba(15,23,42,.24), inset 0 1px 0 #fff; animation: dialog-in .18s ease-out; }
+.dialog-overlay { position: fixed; z-index: 20; top: 0; right: 0; bottom: 0; left: 0; inset: 0; display: flex; align-items: center; justify-content: center; padding: 16px; background: rgba(15,23,42,.46); backdrop-filter: blur(8px); animation: fade-in .15s ease-out; }
+.dialog-card { position: relative; width: 100%; max-width: 360px; width: min(100%, 360px); padding: 24px; border: 1px solid rgba(255,255,255,.72); border-radius: 20px; color: var(--foreground); background: rgba(255,255,255,.96); box-shadow: 0 24px 70px rgba(15,23,42,.24), inset 0 1px 0 #fff; animation: dialog-in .18s ease-out; }
 .dialog-card header { padding-right: 18px; }
 .dialog-card h2 { margin: 0; font-size: 18px; line-height: 26px; font-weight: 600; }
 .dialog-card header p { margin: 6px 0 0; color: var(--muted-foreground); font-size: 13px; line-height: 20px; }
@@ -166,7 +167,7 @@ svg { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round
 .quick-item { height: 44px; min-width: 0; padding: 0 12px; overflow: hidden; border: 1px solid var(--border); border-radius: 12px; color: var(--foreground); background: var(--background); font-size: 14px; font-weight: 500; text-align: left; text-overflow: ellipsis; white-space: nowrap; cursor: pointer; }
 .quick-item:hover { color: var(--theme); border-color: rgba(var(--theme-rgb), .4); background: rgba(var(--theme-rgb), .05); }
 .quick-empty { padding: 28px 0 8px; color: var(--muted-foreground); text-align: center; font-size: 13px; }
-.close-dialog { width: min(100%, 320px); }
+.close-dialog { width: 100%; max-width: 320px; width: min(100%, 320px); }
 .dialog-actions { margin-top: 20px; display: flex; justify-content: flex-end; gap: 8px; }
 .secondary-button, .primary-button, .danger-button { height: 38px; padding: 0 15px; border-radius: 11px; font-size: 14px; cursor: pointer; }
 .secondary-button { border: 1px solid var(--border); background: var(--background); }
@@ -177,7 +178,7 @@ svg { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round
 @keyframes fade-in { from { opacity: 0; } }
 @keyframes dialog-in { from { transform: scale(.97); opacity: .4; } }
 
-.toast-region { position: fixed; z-index: 40; top: max(14px, env(safe-area-inset-top)); left: 50%; width: min(90vw, 420px); transform: translateX(-50%); pointer-events: none; }
+.toast-region { position: fixed; z-index: 40; top: 14px; top: max(14px, env(safe-area-inset-top)); left: 50%; width: 90vw; max-width: 420px; width: min(90vw, 420px); transform: translateX(-50%); pointer-events: none; }
 .toast { margin-bottom: 8px; padding: 11px 14px; border: 1px solid rgba(255,255,255,.75); border-radius: 13px; color: var(--foreground); background: rgba(255,255,255,.92); box-shadow: 0 14px 36px rgba(15,23,42,.16); backdrop-filter: blur(16px); text-align: center; font-size: 13px; animation: toast-in .18s ease-out; }
 .toast.error { color: #b42318; border-color: #fecdca; background: #fff6f5; }
 @keyframes toast-in { from { transform: translateY(-8px); opacity: 0; } }
@@ -204,7 +205,7 @@ svg { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round
   .brand-mark { border-color: rgba(255,255,255,.16); }
   .connection-badge.connecting { color: #fcd34d; border-color: rgba(245,158,11,.35); background: rgba(120,53,15,.35); }
   .chat-header .icon-button { border-color: rgba(255,255,255,.08); background: rgba(255,255,255,.045); box-shadow: 0 2px 8px rgba(0,0,0,.12), inset 0 1px 0 rgba(255,255,255,.045); }
-  #retry-button { color: color-mix(in srgb, var(--theme), #fff 22%); border-color: rgba(var(--theme-rgb), .2); background: rgba(var(--theme-rgb), .12); }
+  #retry-button { color: #8cb5ff; color: color-mix(in srgb, var(--theme), #fff 22%); border-color: rgba(var(--theme-rgb), .2); background: rgba(var(--theme-rgb), .12); }
   .close-button:hover { color: #fca5a5; border-color: rgba(248,113,113,.18); background: rgba(127,29,29,.3); }
   .message-avatar { border-color: rgba(255,255,255,.08); background: rgba(var(--theme-rgb),.16); }
   .message-bubble { border-color: rgba(255,255,255,.08); background: rgba(22,31,48,.95); box-shadow: 0 12px 30px rgba(0,0,0,.18); }
diff --git a/internal/web/supportchat/assets/chat.js b/internal/web/supportchat/assets/chat.js
index dc44641..295637e 100644
--- a/internal/web/supportchat/assets/chat.js
+++ b/internal/web/supportchat/assets/chat.js
@@ -89,13 +89,13 @@
     const userId = (params.get("user_id") || "").trim();
     if (!external_id && userId) {
       external_id = `mall_user:${userId}`;
-      external_name ||= `商城用户 ${userId}`;
+      if (!external_name) external_name = `商城用户 ${userId}`;
     }
     if (!external_id) {
       const storageKey = "agent_desk_guest_id";
       external_id = localStorage.getItem(storageKey) || `guest_${randomId()}`;
       localStorage.setItem(storageKey, external_id);
-      external_name ||= `访客${external_id.slice(-8)}`;
+      if (!external_name) external_name = `访客${external_id.slice(-8)}`;
     }
     return {
       external_id,
@@ -124,7 +124,7 @@
     }
     try {
       const stored = JSON.parse(readSessionStorage(accessTargetStorageKey()) || "null");
-      if ((stored?.type === "card" || stored?.type === "device") && validAccessNumber(stored?.number)) {
+      if (stored && (stored.type === "card" || stored.type === "device") && validAccessNumber(stored.number)) {
         return { type: stored.type, number: String(stored.number).trim() };
       }
     } catch (_) {
@@ -176,10 +176,19 @@
   }
 
   function randomId() {
-    if (window.crypto?.randomUUID) return window.crypto.randomUUID().replaceAll("-", "");
+    if (window.crypto && window.crypto.randomUUID) return window.crypto.randomUUID().replace(/-/g, "");
     return `${Date.now().toString(36)}${Math.random().toString(36).slice(2, 12)}`;
   }
 
+  function lastItem(items) {
+    return Array.isArray(items) && items.length ? items[items.length - 1] : undefined;
+  }
+
+  function replaceChildrenCompat(element, children) {
+    while (element.firstChild) element.removeChild(element.firstChild);
+    (children || []).forEach((child) => element.appendChild(child));
+  }
+
   function clientMessageId(prefix = "support_chat") {
     return `${prefix}_${Date.now()}_${randomId().slice(0, 8)}`;
   }
@@ -199,7 +208,11 @@
     }
     let response;
     try {
-      response = await fetch(`${apiBase}${path}`, { ...options, headers, cache: "no-store", credentials: "include" });
+      response = await fetch(`${apiBase}${path}`, Object.assign({}, options, {
+        headers,
+        cache: "no-store",
+        credentials: "include",
+      }));
     } catch (_) {
       throw new Error("网络连接失败，请检查网络后重试");
     }
@@ -209,8 +222,8 @@
     } catch (_) {
       throw new Error("客服服务暂时不可用，请稍后重试");
     }
-    if (!response.ok || payload?.ok === false || payload?.success === false) {
-      const value = payload?.msg || payload?.message || payload?.code;
+    if (!response.ok || (payload && payload.ok === false) || (payload && payload.success === false)) {
+      const value = payload && (payload.msg || payload.message || payload.code);
       if (accessTarget && isCustomerSessionError(value, response.status)) {
         clearChatBinding();
         window.location.reload();
@@ -228,8 +241,8 @@
 
   function targetQuery(target = accessTarget) {
     const query = new URLSearchParams();
-    if (target?.type === "card") query.set("card_no", target.number);
-    if (target?.type === "device") query.set("device_no", target.number);
+    if (target && target.type === "card") query.set("card_no", target.number);
+    if (target && target.type === "device") query.set("device_no", target.number);
     return query;
   }
 
@@ -243,12 +256,11 @@
   async function h5AccessRequest(path, options = {}) {
     let response;
     try {
-      response = await fetch(h5AccessURL(path), {
-        ...options,
+      response = await fetch(h5AccessURL(path), Object.assign({}, options, {
         cache: "no-store",
         credentials: "include",
-        headers: { Accept: "application/json", ...(options.headers || {}) },
-      });
+        headers: Object.assign({ Accept: "application/json" }, options.headers || {}),
+      }));
     } catch (_) {
       throw new Error("网络连接失败，请检查网络后重试");
     }
@@ -258,8 +270,8 @@
     } catch (_) {
       throw new Error("客服入口暂时不可用，请稍后重试");
     }
-    if (!response.ok || payload?.ok === false || payload?.success === false) {
-      throw new Error(chineseError(payload?.msg || payload?.message || payload?.code));
+    if (!response.ok || (payload && payload.ok === false) || (payload && payload.success === false)) {
+      throw new Error(chineseError(payload && (payload.msg || payload.message || payload.code)));
     }
     return Object.prototype.hasOwnProperty.call(payload || {}, "data") ? payload.data : payload;
   }
@@ -272,8 +284,8 @@
         body: "{}",
         headers: { "Content-Type": "application/json" },
       });
-      const ticket = String(entry?.ticket || "").trim();
-      const binding = String(entry?.session_binding || "").trim();
+      const ticket = String((entry && entry.ticket) || "").trim();
+      const binding = String((entry && entry.session_binding) || "").trim();
       if (!ticket || !binding) throw new Error("客服入口无效，请重试");
       state.chatBinding = binding;
       writeSessionStorage(chatBindingStorageKey(accessTarget), binding);
@@ -366,11 +378,11 @@
   }
 
   async function loadMessages(initial = false) {
-    if (!state.conversation?.id) return;
+    if (!state.conversation || !state.conversation.id) return;
     const result = await request(`/message/list?conversation_id=${state.conversation.id}&limit=50`);
-    const incoming = Array.isArray(result?.results) ? result.results : [];
-    state.cursor = result?.cursor || "";
-    state.hasMore = Boolean(result?.has_more) || incoming.length >= 50;
+    const incoming = result && Array.isArray(result.results) ? result.results : [];
+    state.cursor = (result && result.cursor) || "";
+    state.hasMore = Boolean(result && result.has_more) || incoming.length >= 50;
     state.messages = mergeMessages(state.messages, incoming);
     if (initial) state.initialScrollSettling = true;
     renderMessages();
@@ -382,16 +394,16 @@
   }
 
   async function loadOlder() {
-    if (!state.hasMore || state.loadingOlder || !state.cursor || !state.conversation?.id) return;
+    if (!state.hasMore || state.loadingOlder || !state.cursor || !state.conversation || !state.conversation.id) return;
     state.loadingOlder = true;
     dom.loadMore.disabled = true;
     dom.loadMore.textContent = "正在加载…";
     const oldHeight = dom.scroller.scrollHeight;
     try {
       const result = await request(`/message/list?conversation_id=${state.conversation.id}&limit=50&cursor=${encodeURIComponent(state.cursor)}`);
-      state.cursor = result?.cursor || "";
-      state.hasMore = Boolean(result?.has_more);
-      state.messages = mergeMessages(result?.results || [], state.messages);
+      state.cursor = (result && result.cursor) || "";
+      state.hasMore = Boolean(result && result.has_more);
+      state.messages = mergeMessages((result && result.results) || [], state.messages);
       renderMessages();
       requestAnimationFrame(() => {
         dom.scroller.scrollTop = dom.scroller.scrollHeight - oldHeight;
@@ -406,12 +418,12 @@
     }
   }
 
-  function mergeMessages(...groups) {
+  function mergeMessages(first, second) {
     const map = new Map();
-    groups.flat().forEach((item) => {
-      if (item?.id != null) map.set(String(item.id), item);
-    });
-    return [...map.values()].sort((a, b) => Number(a.id) - Number(b.id));
+    [first, second].forEach((group) => (group || []).forEach((item) => {
+      if (item && item.id != null) map.set(String(item.id), item);
+    }));
+    return Array.from(map.values()).sort((a, b) => Number(a.id) - Number(b.id));
   }
 
   function renderMessages() {
@@ -428,7 +440,7 @@
       }
       fragment.append(createMessageElement(message));
     });
-    dom.list.replaceChildren(fragment);
+    replaceChildrenCompat(dom.list, [fragment]);
     dom.empty.hidden = state.messages.length > 0;
   }
 
@@ -466,15 +478,20 @@
   function avatar(message) {
     const node = document.createElement("span");
     node.className = "message-avatar";
+    const name = senderName(message);
+    const fallback = (name || "客服").slice(0, 1).toUpperCase();
     if (message.sender_avatar) {
       const image = document.createElement("img");
       image.src = message.sender_avatar;
       image.alt = "";
+      image.addEventListener("error", () => {
+        image.remove();
+        node.textContent = fallback;
+      }, { once: true });
       node.append(image);
       return node;
     }
-    const name = senderName(message);
-    node.textContent = (name || "客服").slice(0, 1).toUpperCase();
+    node.textContent = fallback;
     return node;
   }
 
@@ -500,8 +517,8 @@
       gallery.className = `message-image-grid count-${Math.min(assets.length, 9)}`;
       assets.slice(0, 9).forEach((asset) => {
         const image = document.createElement("img");
-        image.src = asset?.url || "";
-        image.alt = asset?.filename || "聊天图片";
+        image.src = (asset && asset.url) || "";
+        image.alt = (asset && asset.filename) || "聊天图片";
         image.loading = "eager";
         image.addEventListener("load", () => {
           if (state.initialScrollSettling) scrollToBottom(false);
@@ -557,23 +574,28 @@
       "EMBED", "FORM", "IFRAME", "INPUT", "LINK", "META", "OBJECT",
       "SCRIPT", "STYLE", "TEMPLATE",
     ]);
-    [...root.querySelectorAll("*")].forEach((node) => {
+    Array.from(root.querySelectorAll("*")).forEach((node) => {
       if (blockedTags.has(node.tagName)) {
-        node.remove();
+        if (node.parentNode) node.parentNode.removeChild(node);
         return;
       }
       if (!allowedTags.has(node.tagName)) {
-        node.replaceWith(...node.childNodes);
+        const parent = node.parentNode;
+        if (parent) {
+          while (node.firstChild) parent.insertBefore(node.firstChild, node);
+          parent.removeChild(node);
+        }
         return;
       }
-      [...node.attributes].forEach((attr) => {
+      Array.from(node.attributes).forEach((attr) => {
         if (node.tagName !== "A" || !["href", "title"].includes(attr.name.toLowerCase())) {
           node.removeAttribute(attr.name);
         }
       });
       if (node.tagName === "A") {
         const href = String(node.getAttribute("href") || "").trim();
-        const scheme = href.match(/^([a-z][a-z0-9+.-]*):/i)?.[1]?.toLowerCase();
+        const schemeMatch = href.match(/^([a-z][a-z0-9+.-]*):/i);
+        const scheme = schemeMatch && schemeMatch[1] ? schemeMatch[1].toLowerCase() : "";
         if (scheme && !["http", "https", "mailto", "tel"].includes(scheme)) {
           node.removeAttribute("href");
         }
@@ -584,7 +606,7 @@
       }
     });
     const fragment = document.createDocumentFragment();
-    [...root.childNodes].forEach((node) => fragment.append(document.importNode(node, true)));
+    Array.from(root.childNodes).forEach((node) => fragment.appendChild(document.importNode(node, true)));
     return fragment;
   }
 
@@ -667,17 +689,19 @@
     }
     const remaining = kind === "image" ? Math.max(0, 9 - state.pendingUploads.length) : 1;
     if (accepted.length > remaining) toast("每次最多发送 9 张图片", true);
-    state.pendingUploads.push(...accepted.slice(0, remaining).map((file) => ({
-      file,
-      kind,
-      previewUrl: kind === "image" ? URL.createObjectURL(file) : "",
-    })));
+    accepted.slice(0, remaining).forEach((file) => {
+      state.pendingUploads.push({
+        file,
+        kind,
+        previewUrl: kind === "image" ? URL.createObjectURL(file) : "",
+      });
+    });
     renderPendingUploads();
     updateAvailability();
   }
 
   function renderPendingUploads() {
-    dom.pendingUploads.replaceChildren();
+    replaceChildrenCompat(dom.pendingUploads, []);
     dom.pendingUploads.hidden = state.pendingUploads.length === 0;
     state.pendingUploads.forEach((pending) => {
       const image = pending.kind === "image";
@@ -740,7 +764,7 @@
       if (pending.previewUrl) URL.revokeObjectURL(pending.previewUrl);
     });
     state.pendingUploads = [];
-    dom.pendingUploads.replaceChildren();
+    replaceChildrenCompat(dom.pendingUploads, []);
     dom.pendingUploads.hidden = true;
     dom.imageInput.value = "";
     dom.fileInput.value = "";
@@ -779,7 +803,7 @@
 
   async function sendComposer() {
     const content = dom.input.value.trim();
-    const pending = [...state.pendingUploads];
+    const pending = state.pendingUploads.slice();
     if ((!content && !pending.length) || state.sending || !canSend()) return;
 
     state.sending = true;
@@ -823,7 +847,7 @@
   }
 
   function renderQuickActions() {
-    dom.quickList.replaceChildren(...state.quickActions.map((action) => {
+    replaceChildrenCompat(dom.quickList, state.quickActions.map((action) => {
       const button = document.createElement("button");
       button.type = "button";
       button.className = "quick-item";
@@ -850,7 +874,7 @@
           client_msg_id: clientMessageId("support_chat_quick"),
         }),
       });
-      state.messages = mergeMessages(state.messages, [result?.customer_message, result?.reply_message].filter(Boolean));
+      state.messages = mergeMessages(state.messages, [result && result.customer_message, result && result.reply_message].filter(Boolean));
       renderMessages();
       scrollToBottom();
     } catch (error) {
@@ -862,8 +886,8 @@
   }
 
   async function markLatestRead() {
-    const latest = state.messages.at(-1);
-    if (!latest || !state.conversation?.id) return;
+    const latest = lastItem(state.messages);
+    if (!latest || !state.conversation || !state.conversation.id) return;
     try {
       await request("/message/read", {
         method: "POST",
@@ -875,7 +899,7 @@
   }
 
   function canSend() {
-    return Boolean(state.conversation?.id) && Number(state.conversation.status) !== 4;
+    return Boolean(state.conversation && state.conversation.id) && Number(state.conversation.status) !== 4;
   }
 
   function updateAvailability() {
@@ -897,7 +921,7 @@
 
   function updateQueueStatus() {
     const conversation = state.conversation;
-    const queued = Number(conversation?.status) === 2 && Number(conversation?.current_assignee_id || 0) === 0;
+    const queued = Number(conversation && conversation.status) === 2 && Number((conversation && conversation.current_assignee_id) || 0) === 0;
     dom.queueStatus.hidden = !queued;
     if (!queued) return;
 
@@ -924,7 +948,7 @@
   }
 
   function currentQueueWaitSeconds() {
-    const baseline = Math.max(0, Number(state.conversation?.queue_wait_seconds || 0));
+    const baseline = Math.max(0, Number((state.conversation && state.conversation.queue_wait_seconds) || 0));
     if (!state.queueSyncedAt) return baseline;
     return baseline + Math.max(0, Math.floor((Date.now() - state.queueSyncedAt) / 1000));
   }
@@ -939,7 +963,7 @@
   }
 
   function syncQueueTimers() {
-    const queued = Number(state.conversation?.status) === 2 && Number(state.conversation?.current_assignee_id || 0) === 0;
+    const queued = Number(state.conversation && state.conversation.status) === 2 && Number((state.conversation && state.conversation.current_assignee_id) || 0) === 0;
     if (!queued) {
       clearQueueTimers();
       return;
@@ -960,10 +984,10 @@
   }
 
   async function refreshConversationQueue() {
-    if (!state.conversation?.id || Number(state.conversation.status) !== 2) return;
+    if (!state.conversation || !state.conversation.id || Number(state.conversation.status) !== 2) return;
     try {
       const latest = await request(`/conversation/${state.conversation.id}`);
-      state.conversation = { ...state.conversation, ...latest };
+      state.conversation = Object.assign({}, state.conversation, latest);
       state.queueSyncedAt = Date.now();
       updateAvailability();
     } catch (_) {
@@ -982,7 +1006,8 @@
     const base = apiBase.startsWith("http://") || apiBase.startsWith("https://")
       ? apiBase.replace(/^http/, "ws")
       : `${window.location.protocol === "https:" ? "wss:" : "ws:"}//${window.location.host}${apiBase.startsWith("/") ? "" : "/"}${apiBase}`;
-    const query = new URLSearchParams({ channel_id: channelId });
+    const query = new URLSearchParams();
+    query.set("channel_id", channelId);
     if (accessTarget) {
       query.set("h5_chat_session", "required");
       query.set("h5_chat_binding", state.chatBinding);
@@ -993,7 +1018,7 @@
   }
 
   function connectSocket() {
-    if (!state.conversation?.id || Number(state.conversation.status) === 4) return;
+    if (!state.conversation || !state.conversation.id || Number(state.conversation.status) === 4) return;
     clearRealtimeTimers();
     if (state.socket) {
       const oldSocket = state.socket;
@@ -1043,33 +1068,35 @@
     } catch (_) {
       return;
     }
-    const payload = event?.data;
-    if (event?.type === "resyncRequired") {
+    const payload = event && event.data;
+    if (event && event.type === "resyncRequired") {
       loadMessages(false).catch(() => {});
       return;
     }
-    if (!payload || Number(payload.conversation_id) !== Number(state.conversation?.id)) return;
+    if (!payload || Number(payload.conversation_id) !== Number(state.conversation && state.conversation.id)) return;
     if (event.type === "message.created") {
       const message = normalizeRealtimeMessage(payload);
       if (!message) {
         loadMessages(false).catch(() => {});
         return;
       }
-      const previousLastId = state.messages.at(-1)?.id;
+      const previousLast = lastItem(state.messages);
+      const previousLastId = previousLast && previousLast.id;
       state.messages = mergeMessages(state.messages, [message]);
       state.conversation.last_message_id = message.id;
       state.conversation.last_message_at = message.sent_at || state.conversation.last_message_at;
       renderMessages();
-      if (state.messages.at(-1)?.id !== previousLastId) {
+      const currentLast = lastItem(state.messages);
+      if ((currentLast && currentLast.id) !== previousLastId) {
         scrollToBottom();
         markLatestRead();
       }
       return;
     }
     if (String(event.type || "").startsWith("conversation.")) {
-      const patch = { ...payload };
+      const patch = Object.assign({}, payload);
       delete patch.conversation_id;
-      state.conversation = { ...state.conversation, ...patch };
+      state.conversation = Object.assign({}, state.conversation, patch);
       state.queueSyncedAt = Date.now();
       applyReadState(payload);
       renderMessages();
@@ -1082,7 +1109,7 @@
   }
 
   function normalizeRealtimeMessage(payload) {
-    if (payload.message?.id) return payload.message;
+    if (payload.message && payload.message.id) return payload.message;
     const id = Number(payload.message_id || 0);
     const conversationId = Number(payload.conversation_id || 0);
     if (!id || !conversationId) return null;
@@ -1106,15 +1133,14 @@
   function applyReadState(payload) {
     const agentReadId = Number(payload.agent_last_read_message_id || 0);
     const customerReadId = Number(payload.customer_last_read_message_id || 0);
-    state.messages = state.messages.map((message) => ({
-      ...message,
+    state.messages = state.messages.map((message) => Object.assign({}, message, {
       agent_read: message.agent_read || (agentReadId > 0 && Number(message.id) <= agentReadId),
       customer_read: message.customer_read || (customerReadId > 0 && Number(message.id) <= customerReadId),
     }));
   }
 
   function scheduleReconnect() {
-    if (!state.allowReconnect || state.reconnectTimer || !state.conversation?.id || Number(state.conversation.status) === 4) return;
+    if (!state.allowReconnect || state.reconnectTimer || !state.conversation || !state.conversation.id || Number(state.conversation.status) === 4) return;
     const delay = Math.min(2000 * 2 ** state.reconnectAttempt, 30000);
     state.reconnectTimer = window.setTimeout(() => {
       state.reconnectTimer = null;
@@ -1144,7 +1170,7 @@
   }
 
   async function retry() {
-    if (!state.initialized || !state.conversation?.id) {
+    if (!state.initialized || !state.conversation || !state.conversation.id) {
       dom.loading.hidden = false;
       dom.empty.hidden = true;
       await init();
@@ -1161,7 +1187,7 @@
 
   async function closeConversation() {
     if (state.closing) return;
-    if (!state.conversation?.id) {
+    if (!state.conversation || !state.conversation.id) {
       closeCloseDialog();
       closePage();
       return;
@@ -1175,7 +1201,7 @@
         method: "POST",
         body: JSON.stringify({ conversation_id: state.conversation.id }),
       });
-      state.conversation = { ...state.conversation, status: 4 };
+      state.conversation = Object.assign({}, state.conversation, { status: 4 });
       disconnectSocket(false);
       clearCustomerAccessState();
       clearPendingUploads();
@@ -1229,7 +1255,7 @@
       const height = dom.scroller.scrollHeight;
       stableTicks = height === lastHeight ? stableTicks + 1 : 0;
       lastHeight = height;
-      const imagesReady = [...dom.list.querySelectorAll("img")].every((image) => image.complete);
+      const imagesReady = Array.from(dom.list.querySelectorAll("img")).every((image) => image.complete);
       if ((imagesReady && stableTicks >= 4) || Date.now() - startedAt >= 6000) {
         dom.scroller.scrollTop = dom.scroller.scrollHeight;
         state.initialScrollSettling = false;
@@ -1323,7 +1349,7 @@
       }
     });
     window.addEventListener("message", (event) => {
-      const type = event.data?.type;
+      const type = event.data && event.data.type;
       if (type === "agent-desk:open" && state.initialized && !state.socket) connectSocket();
       if (type === "agent-desk:minimize") disconnectSocket(false);
     });
diff --git a/internal/web/supportchat/handler_test.go b/internal/web/supportchat/handler_test.go
index 1bb2e5a..49cf1cf 100644
--- a/internal/web/supportchat/handler_test.go
+++ b/internal/web/supportchat/handler_test.go
@@ -116,6 +116,7 @@ func TestSupportChatUsesRealtimeUIWithoutMessagePolling(t *testing.T) {
 		"你可以继续留言",
 		"等待期间可以继续留言",
 		`String(event.type || "").startsWith("conversation.")`,
+		`image.addEventListener("error"`,
 	} {
 		if !strings.Contains(source, marker) {
 			t.Fatalf("support chat queue flow does not contain %q", marker)
@@ -129,6 +130,54 @@ func TestSupportChatUsesRealtimeUIWithoutMessagePolling(t *testing.T) {
 	}
 }
 
+func TestSupportChatKeepsOlderMobileWebViewsCompatible(t *testing.T) {
+	script, err := assets.ReadFile("assets/chat.js")
+	if err != nil {
+		t.Fatalf("read support chat script: %v", err)
+	}
+	source := string(script)
+	for _, forbidden := range []string{
+		"?.",
+		"??",
+		"||=",
+		".at(",
+		".flat(",
+		".replaceAll(",
+		".replaceChildren(",
+	} {
+		if strings.Contains(source, forbidden) {
+			t.Fatalf("support chat must not require newer mobile JavaScript API or syntax %q", forbidden)
+		}
+	}
+	for _, marker := range []string{
+		"function lastItem",
+		"function replaceChildrenCompat",
+		`window.crypto && window.crypto.randomUUID`,
+		`Array.from(map.values())`,
+	} {
+		if !strings.Contains(source, marker) {
+			t.Fatalf("support chat compatibility flow does not contain %q", marker)
+		}
+	}
+
+	stylesheet, err := assets.ReadFile("assets/chat.css")
+	if err != nil {
+		t.Fatalf("read support chat stylesheet: %v", err)
+	}
+	css := string(stylesheet)
+	for _, fallback := range []string{
+		`background: linear-gradient(145deg, #3c80fb, #4c66ea);`,
+		`background: linear-gradient(135deg, #397ffb, #5368ed);`,
+		`background: #eaf2ff;`,
+		`top: 0; right: 0; bottom: 0; left: 0; inset: 0;`,
+		`width: 100%; max-width: 360px; width: min(100%, 360px);`,
+	} {
+		if !strings.Contains(css, fallback) {
+			t.Fatalf("support chat stylesheet does not contain older mobile fallback %q", fallback)
+		}
+	}
+}
+
 func TestSupportChatStagesUploadsUntilExplicitSend(t *testing.T) {
 	script, err := assets.ReadFile("assets/chat.js")
 	if err != nil {