diff --git a/src/components/usage/RequestEventsDetailsCard.tsx b/src/components/usage/RequestEventsDetailsCard.tsx
index 1c6d4b2..14e7bf1 100644
--- a/src/components/usage/RequestEventsDetailsCard.tsx
+++ b/src/components/usage/RequestEventsDetailsCard.tsx
@@ -12,6 +12,7 @@ import {
   collectUsageDetails,
   extractTotalTokens
 } from '@/utils/usage';
+import { downloadBlob } from '@/utils/download';
 import styles from '@/pages/UsagePage.module.scss';
 
 const ALL_FILTER = '__all__';
@@ -53,17 +54,9 @@ const toNumber = (value: unknown): number => {
 
 const encodeCsv = (value: string | number): string => {
   const text = String(value ?? '');
-  return `"${text.replace(/"/g, '""')}"`;
-};
-
-const downloadFile = (filename: string, content: string, mimeType: string) => {
-  const blob = new Blob([content], { type: mimeType });
-  const url = window.URL.createObjectURL(blob);
-  const a = document.createElement('a');
-  a.href = url;
-  a.download = filename;
-  a.click();
-  window.URL.revokeObjectURL(url);
+  const trimmedLeft = text.replace(/^\s+/, '');
+  const safeText = trimmedLeft && /^[=+\-@]/.test(trimmedLeft) ? `'${text}` : text;
+  return `"${safeText.replace(/"/g, '""')}"`;
 };
 
 type CredentialInfo = {
@@ -370,7 +363,10 @@ export function RequestEventsDetailsCard({
 
     const content = [csvHeader.join(','), ...csvRows].join('\n');
     const fileTime = new Date().toISOString().replace(/[:.]/g, '-');
-    downloadFile(`usage-events-${fileTime}.csv`, content, 'text/csv;charset=utf-8');
+    downloadBlob({
+      filename: `usage-events-${fileTime}.csv`,
+      blob: new Blob([content], { type: 'text/csv;charset=utf-8' })
+    });
   };
 
   const handleExportJson = () => {
@@ -394,7 +390,10 @@ export function RequestEventsDetailsCard({
 
     const content = JSON.stringify(payload, null, 2);
     const fileTime = new Date().toISOString().replace(/[:.]/g, '-');
-    downloadFile(`usage-events-${fileTime}.json`, content, 'application/json;charset=utf-8');
+    downloadBlob({
+      filename: `usage-events-${fileTime}.json`,
+      blob: new Blob([content], { type: 'application/json;charset=utf-8' })
+    });
   };
 
   return (
diff --git a/src/components/usage/hooks/useUsageData.ts b/src/components/usage/hooks/useUsageData.ts
index e68cc0b..4816cef 100644
--- a/src/components/usage/hooks/useUsageData.ts
+++ b/src/components/usage/hooks/useUsageData.ts
@@ -2,6 +2,7 @@ import { useEffect, useState, useCallback, useRef } from 'react';
 import { useTranslation } from 'react-i18next';
 import { USAGE_STATS_STALE_TIME_MS, useNotificationStore, useUsageStatsStore } from '@/stores';
 import { usageApi } from '@/services/api/usage';
+import { downloadBlob } from '@/utils/download';
 import { loadModelPrices, saveModelPrices, type ModelPrice } from '@/utils/usage';
 
 export interface UsagePayload {
@@ -62,13 +63,10 @@ export function useUsageData(): UseUsageDataReturn {
         ? new Date().toISOString()
         : exportedAt.toISOString();
       const filename = `usage-export-${safeTimestamp.replace(/[:.]/g, '-')}.json`;
-      const blob = new Blob([JSON.stringify(data ?? {}, null, 2)], { type: 'application/json' });
-      const url = window.URL.createObjectURL(blob);
-      const link = document.createElement('a');
-      link.href = url;
-      link.download = filename;
-      link.click();
-      window.URL.revokeObjectURL(url);
+      downloadBlob({
+        filename,
+        blob: new Blob([JSON.stringify(data ?? {}, null, 2)], { type: 'application/json' })
+      });
       showNotification(t('usage_stats.export_success'), 'success');
     } catch (err: unknown) {
       const message = err instanceof Error ? err.message : '';
diff --git a/src/features/authFiles/hooks/useAuthFilesData.ts b/src/features/authFiles/hooks/useAuthFilesData.ts
index e74781a..a3d2c08 100644
--- a/src/features/authFiles/hooks/useAuthFilesData.ts
+++ b/src/features/authFiles/hooks/useAuthFilesData.ts
@@ -6,6 +6,7 @@ import { useNotificationStore } from '@/stores';
 import type { AuthFileItem } from '@/types';
 import { formatFileSize } from '@/utils/format';
 import { MAX_AUTH_FILE_SIZE } from '@/utils/constants';
+import { downloadBlob } from '@/utils/download';
 import { getTypeLabel, isRuntimeOnlyAuthFile } from '@/features/authFiles/constants';
 
 type DeleteAllOptions = {
@@ -316,12 +317,7 @@ export function useAuthFilesData(options: UseAuthFilesDataOptions): UseAuthFiles
           { responseType: 'blob' }
         );
         const blob = new Blob([response.data]);
-        const url = window.URL.createObjectURL(blob);
-        const a = document.createElement('a');
-        a.href = url;
-        a.download = name;
-        a.click();
-        window.URL.revokeObjectURL(url);
+        downloadBlob({ filename: name, blob });
         showNotification(t('auth_files.download_success'), 'success');
       } catch (err: unknown) {
         const errorMessage = err instanceof Error ? err.message : '';
diff --git a/src/pages/LogsPage.tsx b/src/pages/LogsPage.tsx
index 519cb3a..34110f1 100644
--- a/src/pages/LogsPage.tsx
+++ b/src/pages/LogsPage.tsx
@@ -24,6 +24,7 @@ import { logsApi } from '@/services/api/logs';
 import { usageApi } from '@/services/api/usage';
 import type { AuthFileItem } from '@/types';
 import { copyToClipboard } from '@/utils/clipboard';
+import { downloadBlob } from '@/utils/download';
 import { MANAGEMENT_API_PREFIX } from '@/utils/constants';
 import { formatUnixTimestamp } from '@/utils/format';
 import {
@@ -710,13 +711,7 @@ export function LogsPage() {
 
   const downloadLogs = () => {
     const text = logState.buffer.join('\n');
-    const blob = new Blob([text], { type: 'text/plain' });
-    const url = window.URL.createObjectURL(blob);
-    const a = document.createElement('a');
-    a.href = url;
-    a.download = 'logs.txt';
-    a.click();
-    window.URL.revokeObjectURL(url);
+    downloadBlob({ filename: 'logs.txt', blob: new Blob([text], { type: 'text/plain' }) });
     showNotification(t('logs.download_success'), 'success');
   };
 
@@ -747,13 +742,7 @@ export function LogsPage() {
   const downloadErrorLog = async (name: string) => {
     try {
       const response = await logsApi.downloadErrorLog(name);
-      const blob = new Blob([response.data], { type: 'text/plain' });
-      const url = window.URL.createObjectURL(blob);
-      const a = document.createElement('a');
-      a.href = url;
-      a.download = name;
-      a.click();
-      window.URL.revokeObjectURL(url);
+      downloadBlob({ filename: name, blob: new Blob([response.data], { type: 'text/plain' }) });
       showNotification(t('logs.error_log_download_success'), 'success');
     } catch (err: unknown) {
       const message = getErrorMessage(err);
@@ -1187,13 +1176,10 @@ export function LogsPage() {
     setRequestLogDownloading(true);
     try {
       const response = await logsApi.downloadRequestLogById(id);
-      const blob = new Blob([response.data], { type: 'text/plain' });
-      const url = window.URL.createObjectURL(blob);
-      const a = document.createElement('a');
-      a.href = url;
-      a.download = `request-${id}.log`;
-      a.click();
-      window.URL.revokeObjectURL(url);
+      downloadBlob({
+        filename: `request-${id}.log`,
+        blob: new Blob([response.data], { type: 'text/plain' })
+      });
       showNotification(t('logs.request_log_download_success'), 'success');
       setRequestLogId(null);
     } catch (err: unknown) {
diff --git a/src/utils/download.ts b/src/utils/download.ts
new file mode 100644
index 0000000..2dbc497
--- /dev/null
+++ b/src/utils/download.ts
@@ -0,0 +1,22 @@
+export type DownloadBlobOptions = {
+  filename: string;
+  blob: Blob;
+  revokeDelayMs?: number;
+};
+
+export function downloadBlob({ filename, blob, revokeDelayMs = 1000 }: DownloadBlobOptions) {
+  const url = window.URL.createObjectURL(blob);
+  const link = document.createElement('a');
+  link.href = url;
+  link.download = filename;
+  link.rel = 'noopener';
+  link.style.display = 'none';
+  document.body.appendChild(link);
+  link.click();
+
+  window.setTimeout(() => {
+    window.URL.revokeObjectURL(url);
+    link.remove();
+  }, revokeDelayMs);
+}
+