diff --git a/src/main/main.ts b/src/main/main.ts
index b4e5e83..ac349c6 100644
--- a/src/main/main.ts
+++ b/src/main/main.ts
@@ -25,15 +25,17 @@ let mainWindow: BrowserWindow | null = null;
 let loadingWindow: BrowserWindow | null = null;
 let nodecgProcess: ChildProcess | null = null;
 let lastNodeCGOutput = "";
+let stopNodeCGPromise: Promise<void> | null = null;
+let isQuitting = false;
 
 function createMainWindow(): BrowserWindow {
   const win = new BrowserWindow({
     show: false,
     title: APP_TITLE,
-    width: 1440,
-    height: 900,
-    minWidth: 960,
-    minHeight: 640,
+    width: 1280,
+    height: 800,
+    minWidth: 800,
+    minHeight: 500,
     backgroundColor: "#0f0f0f",
     webPreferences: {
       contextIsolation: true,
@@ -73,8 +75,8 @@ function createLoadingWindow(): BrowserWindow {
     show: false,
     frame: false,
     title: APP_TITLE,
-    width: 420,
-    height: 280,
+    width: 300,
+    height: 300,
     resizable: false,
     movable: true,
     minimizable: false,
@@ -180,6 +182,7 @@ function startNodeCG(): ChildProcess {
       ...(USE_SYSTEM_NODE ? {} : { ELECTRON_RUN_AS_NODE: "1" }),
     },
     stdio: ["ignore", "pipe", "pipe"],
+    detached: process.platform !== "win32",
     shell: process.platform === "win32",
   });
 
@@ -277,23 +280,76 @@ async function launch(): Promise<void> {
   }
 }
 
-function stopNodeCG(): void {
+function killNodeCGProcessTree(pid: number, signal: NodeJS.Signals): boolean {
+  if (process.platform === "win32") {
+    const force = signal === "SIGKILL" ? "/F" : "";
+    const killer = spawn("taskkill", ["/pid", String(pid), "/T", ...(force ? [force] : [])], {
+      stdio: "ignore",
+      shell: true,
+    });
+
+    killer.on("error", (error) => {
+      log(`taskkill error for pid=${pid}`, error);
+    });
+
+    return true;
+  }
+
+  try {
+    process.kill(-pid, signal);
+    return true;
+  } catch {
+    try {
+      process.kill(pid, signal);
+      return true;
+    } catch {
+      return false;
+    }
+  }
+}
+
+function stopNodeCG(): Promise<void> {
+  if (stopNodeCGPromise) {
+    return stopNodeCGPromise;
+  }
+
   if (!nodecgProcess || nodecgProcess.killed) {
-    return;
+    return Promise.resolve();
   }
 
   const processToStop = nodecgProcess;
   const pid = processToStop.pid;
 
-  log(`Stopping NodeCG pid=${pid}`);
-  processToStop.kill("SIGTERM");
+  if (typeof pid !== "number") {
+    log("NodeCG pid unavailable, skipping graceful stop");
+    return Promise.resolve();
+  }
 
-  setTimeout(() => {
-    if (processToStop.exitCode === null && processToStop.signalCode === null) {
-      log(`NodeCG did not exit after SIGTERM, forcing SIGKILL pid=${pid}`);
-      processToStop.kill("SIGKILL");
-    }
-  }, Math.max(0, NODECG_KILL_TIMEOUT_MS));
+  log(`Stopping NodeCG pid=${pid}`);
+  killNodeCGProcessTree(pid, "SIGTERM");
+
+  stopNodeCGPromise = new Promise((resolve) => {
+    const complete = () => {
+      if (nodecgProcess === processToStop) {
+        nodecgProcess = null;
+      }
+      stopNodeCGPromise = null;
+      resolve();
+    };
+
+    processToStop.once("exit", () => {
+      complete();
+    });
+
+    setTimeout(() => {
+      if (processToStop.exitCode === null && processToStop.signalCode === null) {
+        log(`NodeCG did not exit after SIGTERM, forcing SIGKILL pid=${pid}`);
+        killNodeCGProcessTree(pid, "SIGKILL");
+      }
+    }, Math.max(0, NODECG_KILL_TIMEOUT_MS));
+  });
+
+  return stopNodeCGPromise;
 }
 
 function log(...args: unknown[]): void {
@@ -331,8 +387,17 @@ app.on("window-all-closed", () => {
   }
 });
 
-app.on("before-quit", () => {
-  stopNodeCG();
+app.on("before-quit", (event) => {
+  if (isQuitting) {
+    return;
+  }
+
+  event.preventDefault();
+  isQuitting = true;
+
+  stopNodeCG().finally(() => {
+    app.quit();
+  });
 });
 
 app.on("will-quit", () => {