diff --git a/src/components/proxy/ClaudeDesktopRouteToggle.tsx b/src/components/proxy/ClaudeDesktopRouteToggle.tsx
index bf9aa950f..df6e8ffab 100644
--- a/src/components/proxy/ClaudeDesktopRouteToggle.tsx
+++ b/src/components/proxy/ClaudeDesktopRouteToggle.tsx
@@ -84,7 +84,7 @@ export function ClaudeDesktopRouteToggle({
           className={cn(
             "h-4 w-4 transition-colors",
             isRunning
-              ? "text-emerald-500 animate-pulse"
+              ? "text-emerald-500 status-heartbeat"
               : "text-muted-foreground",
           )}
         />
diff --git a/src/components/proxy/FailoverToggle.tsx b/src/components/proxy/FailoverToggle.tsx
index 739fb03b7..8f44079c6 100644
--- a/src/components/proxy/FailoverToggle.tsx
+++ b/src/components/proxy/FailoverToggle.tsx
@@ -72,7 +72,7 @@ export function FailoverToggle({ className, activeApp }: FailoverToggleProps) {
           className={cn(
             "h-4 w-4 transition-colors",
             isEnabled
-              ? "text-emerald-500 animate-pulse"
+              ? "text-emerald-500 status-heartbeat"
               : "text-muted-foreground",
           )}
         />
diff --git a/src/components/proxy/ProxyToggle.tsx b/src/components/proxy/ProxyToggle.tsx
index fa2993d40..3c566556a 100644
--- a/src/components/proxy/ProxyToggle.tsx
+++ b/src/components/proxy/ProxyToggle.tsx
@@ -75,7 +75,7 @@ export function ProxyToggle({ className, activeApp }: ProxyToggleProps) {
           className={cn(
             "h-4 w-4 transition-colors",
             takeoverEnabled
-              ? "text-emerald-500 animate-pulse"
+              ? "text-emerald-500 status-heartbeat"
               : "text-muted-foreground",
           )}
         />
diff --git a/src/components/settings/ProxyTabContent.tsx b/src/components/settings/ProxyTabContent.tsx
index 6f33cf6bc..4c985ebbe 100644
--- a/src/components/settings/ProxyTabContent.tsx
+++ b/src/components/settings/ProxyTabContent.tsx
@@ -118,7 +118,7 @@ export function ProxyTabContent({
                 className="gap-1.5 h-6 ml-auto mr-2"
               >
                 <Activity
-                  className={`h-3 w-3 ${isRunning ? "animate-pulse" : ""}`}
+                  className={`h-3 w-3 ${isRunning ? "status-heartbeat" : ""}`}
                 />
                 {isRunning
                   ? t("settings.advanced.proxy.running")
diff --git a/src/index.css b/src/index.css
index 5a1fbcb9e..f44492a0d 100644
--- a/src/index.css
+++ b/src/index.css
@@ -145,6 +145,35 @@ html.dark {
   color-scheme: dark;
 }
 
+.status-heartbeat {
+  opacity: 1;
+  transition-property: color, opacity;
+  transition-duration: 150ms, 300ms;
+  transition-timing-function: ease, ease-out;
+}
+
+html[data-window-active="true"][data-status-heartbeat="true"]
+  .status-heartbeat {
+  opacity: 0.5;
+}
+
+html[data-window-active="false"] .status-heartbeat {
+  opacity: 1;
+  transition-duration: 0s;
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .status-heartbeat {
+    opacity: 1;
+    transition-property: color;
+  }
+
+  html[data-window-active="true"][data-status-heartbeat="true"]
+    .status-heartbeat {
+    opacity: 1;
+  }
+}
+
 ::-webkit-scrollbar {
   display: none;
 }
diff --git a/src/lib/windowActivity.ts b/src/lib/windowActivity.ts
new file mode 100644
index 000000000..3fbd1be27
--- /dev/null
+++ b/src/lib/windowActivity.ts
@@ -0,0 +1,61 @@
+import { isTauri } from "@tauri-apps/api/core";
+import { getCurrentWindow } from "@tauri-apps/api/window";
+
+const HEARTBEAT_INTERVAL_MS = 3000;
+const HEARTBEAT_DIM_MS = 300;
+
+let initialized = false;
+let heartbeatInterval: number | undefined;
+let heartbeatReset: number | undefined;
+
+function stopHeartbeat() {
+  if (heartbeatInterval !== undefined) {
+    window.clearInterval(heartbeatInterval);
+    heartbeatInterval = undefined;
+  }
+  if (heartbeatReset !== undefined) {
+    window.clearTimeout(heartbeatReset);
+    heartbeatReset = undefined;
+  }
+  delete document.documentElement.dataset.statusHeartbeat;
+}
+
+function startHeartbeat() {
+  stopHeartbeat();
+  heartbeatInterval = window.setInterval(() => {
+    document.documentElement.dataset.statusHeartbeat = "true";
+    heartbeatReset = window.setTimeout(() => {
+      delete document.documentElement.dataset.statusHeartbeat;
+      heartbeatReset = undefined;
+    }, HEARTBEAT_DIM_MS);
+  }, HEARTBEAT_INTERVAL_MS);
+}
+
+function setWindowActive(active: boolean) {
+  document.documentElement.dataset.windowActive = String(active);
+
+  if (active) {
+    startHeartbeat();
+  } else {
+    stopHeartbeat();
+  }
+}
+
+export function initializeWindowActivity() {
+  if (initialized) return;
+  initialized = true;
+
+  setWindowActive(document.hasFocus());
+
+  // Browser focus events are a fallback for non-Tauri renderer tests and dev mode.
+  window.addEventListener("focus", () => setWindowActive(true));
+  window.addEventListener("blur", () => setWindowActive(false));
+
+  if (isTauri()) {
+    void getCurrentWindow()
+      .onFocusChanged(({ payload }) => setWindowActive(payload))
+      .catch((error) => {
+        console.error("Failed to observe window focus changes", error);
+      });
+  }
+}
diff --git a/src/main.tsx b/src/main.tsx
index bc15c43ee..2022fb43a 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -23,6 +23,7 @@ import {
   MODELS_DEV_SYNC_CONFIG_QUERY_KEY,
   syncModelsDevPricingOnStartup,
 } from "./lib/modelsDevAutoSync";
+import { initializeWindowActivity } from "@/lib/windowActivity";
 
 installGlobalErrorHandlers();
 
@@ -114,6 +115,8 @@ async function bootstrap() {
     reportFrontendError("get_init_error", e);
   }
 
+  initializeWindowActivity();
+
   ReactDOM.createRoot(document.getElementById("root")!).render(
     <React.StrictMode>
       <FrontendErrorBoundary>