feat：语音对话优化

frontend/src/App.css

@@ -590,7 +590,6 @@ body {
   animation: pulse 1.5s cubic-bezier(0.25, 0.46, 0.45, 0.94) infinite;
 }
 
-.video-indicator--loading { color: var(--color-warning); }
 .video-indicator--audio { left: auto; right: 16px; color: var(--color-primary); }
 .video-indicator--error { color: var(--color-error); animation: none; }
 
@@ -651,26 +650,6 @@ body {
   animation: pulse 2s cubic-bezier(0.25, 0.46, 0.45, 0.94) infinite;
 }
 
-.video-overlay {
-  position: absolute;
-  inset: 0;
-  background: rgba(10, 10, 15, 0.4);
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  backdrop-filter: blur(3px);
-  -webkit-backdrop-filter: blur(3px);
-}
-
-.video-overlay__spinner {
-  width: 36px;
-  height: 36px;
-  border: 2.5px solid rgba(255, 255, 255, 0.15);
-  border-top-color: rgba(255, 255, 255, 0.8);
-  border-radius: 50%;
-  animation: spin 0.8s linear infinite;
-}
-
 /* ---- 视频控制栏 ---- */
 
 .video-controls {
@@ -998,6 +977,52 @@ body {
   border: 1px solid rgba(251, 191, 36, 0.15);
 }
 
+.system-message--info {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 8px;
+  background: rgba(59, 130, 246, 0.06);
+  color: var(--color-text-muted);
+  border: 1px solid rgba(59, 130, 246, 0.12);
+}
+
+/* ---- Typing Indicator（跳动点） ---- */
+
+.typing-indicator {
+  display: inline-flex;
+  align-items: center;
+  gap: 4px;
+  padding: 2px 0;
+}
+
+.typing-indicator__dot {
+  width: 6px;
+  height: 6px;
+  border-radius: 50%;
+  background: var(--color-text-muted);
+  animation: typing-bounce 1.2s ease-in-out infinite;
+}
+
+.typing-indicator__dot:nth-child(2) {
+  animation-delay: 0.2s;
+}
+
+.typing-indicator__dot:nth-child(3) {
+  animation-delay: 0.4s;
+}
+
+@keyframes typing-bounce {
+  0%, 60%, 100% {
+    opacity: 0.3;
+    transform: translateY(0);
+  }
+  30% {
+    opacity: 1;
+    transform: translateY(-4px);
+  }
+}
+
 /* ---- Drawer (Config Panel) ---- */
 
 .drawer-overlay {