diff --git a/frontend/src/api/client.ts b/frontend/src/api/client.ts
index f9430ad..32bda97 100644
--- a/frontend/src/api/client.ts
+++ b/frontend/src/api/client.ts
@@ -3,8 +3,7 @@
  */
 import { useAuthStore } from '@/stores/auth'
 import { pinia } from '@/stores'
-
-const API_BASE = (import.meta.env.VITE_API_BASE_URL as string | undefined) ?? '/api/v1'
+import { fetchApi } from '@/config/apiBase'
 
 // 后端返回的错误消息中英映射
 const MESSAGE_MAP: Record<string, string> = {
@@ -57,21 +56,22 @@ async function handleResponse<T>(response: Response): Promise<T> {
 
 /** GET 请求 */
 export async function apiGet<T>(path: string, params?: Record<string, string | number>): Promise<T> {
-  let url = `${API_BASE}${path}`
+  let requestPath = path
   if (params) {
     const searchParams = new URLSearchParams()
     for (const [key, value] of Object.entries(params)) {
       searchParams.set(key, String(value))
     }
-    url += `?${searchParams.toString()}`
+    const separator = requestPath.includes('?') ? '&' : '?'
+    requestPath += `${separator}${searchParams.toString()}`
   }
-  const response = await fetch(url, { method: 'GET', headers: getAuthHeaders() })
+  const response = await fetchApi(requestPath, { method: 'GET', headers: getAuthHeaders() })
   return handleResponse<T>(response)
 }
 
 /** POST 请求 */
 export async function apiPost<T>(path: string, body?: unknown): Promise<T> {
-  const response = await fetch(`${API_BASE}${path}`, {
+  const response = await fetchApi(path, {
     method: 'POST',
     headers: getAuthHeaders(),
     body: body !== undefined ? JSON.stringify(body) : undefined,
@@ -81,7 +81,7 @@ export async function apiPost<T>(path: string, body?: unknown): Promise<T> {
 
 /** PATCH 请求 */
 export async function apiPatch<T>(path: string, body: unknown): Promise<T> {
-  const response = await fetch(`${API_BASE}${path}`, {
+  const response = await fetchApi(path, {
     method: 'PATCH',
     headers: getAuthHeaders(),
     body: JSON.stringify(body),
@@ -91,7 +91,7 @@ export async function apiPatch<T>(path: string, body: unknown): Promise<T> {
 
 /** DELETE 请求 */
 export async function apiDelete(path: string): Promise<void> {
-  const response = await fetch(`${API_BASE}${path}`, {
+  const response = await fetchApi(path, {
     method: 'DELETE',
     headers: getAuthHeaders(),
   })
diff --git a/frontend/src/auth.api.ts b/frontend/src/auth.api.ts
index 1fb0cf9..03d4bd0 100644
--- a/frontend/src/auth.api.ts
+++ b/frontend/src/auth.api.ts
@@ -5,8 +5,7 @@ import type {
   MessageResponse,
   RegisterPayload,
 } from './auth.types'
-
-const API_BASE_URL = (import.meta.env.VITE_API_BASE_URL as string | undefined) ?? '/api/v1'
+import { fetchApi } from '@/config/apiBase'
 
 type JsonValue = object | null
 
@@ -40,7 +39,7 @@ function localizeDetail(detail: string): string {
 }
 
 async function request<T>(path: string, payload: JsonValue): Promise<T> {
-  const response = await fetch(`${API_BASE_URL}${path}`, {
+  const response = await fetchApi(path, {
     method: 'POST',
     headers: {
       'Content-Type': 'application/json',
diff --git a/frontend/src/config/apiBase.ts b/frontend/src/config/apiBase.ts
new file mode 100644
index 0000000..a6d5d50
--- /dev/null
+++ b/frontend/src/config/apiBase.ts
@@ -0,0 +1,116 @@
+const API_PREFIX = '/api/v1'
+const LAN_BACKEND_ORIGIN = 'http://10.252.130.135:8000'
+const PUBLIC_BACKEND_ORIGIN = 'http://47.107.130.88:51290'
+const PROBE_TIMEOUT_MS = 1200
+
+const LAN_API_BASE_URL = `${LAN_BACKEND_ORIGIN}${API_PREFIX}`
+const PUBLIC_API_BASE_URL = `${PUBLIC_BACKEND_ORIGIN}${API_PREFIX}`
+const ENV_API_BASE_URL = import.meta.env.VITE_API_BASE_URL as string | undefined
+
+const EXPECTED_OPENAPI_PATHS = ['/api/v1/auth/login', '/api/v1/events/unified']
+
+let detectedApiBaseUrl: string | null = ENV_API_BASE_URL ?? null
+let detectPromise: Promise<string> | null = null
+
+function normalizePath(path: string): string {
+  if (!path) return '/'
+  return path.startsWith('/') ? path : `/${path}`
+}
+
+function buildUrl(base: string, path: string): string {
+  return `${base}${normalizePath(path)}`
+}
+
+function isPrivateIpv4(hostname: string): boolean {
+  const parts = hostname.split('.').map((part) => Number.parseInt(part, 10))
+  if (parts.length !== 4 || parts.some((part) => Number.isNaN(part) || part < 0 || part > 255)) {
+    return false
+  }
+
+  const a = parts[0] as number
+  const b = parts[1] as number
+  if (a === 10) return true
+  if (a === 172 && b >= 16 && b <= 31) return true
+  if (a === 192 && b === 168) return true
+  if (a === 127) return true
+  return false
+}
+
+function isLanHostname(hostname: string): boolean {
+  const normalized = hostname.toLowerCase()
+  if (normalized === 'localhost' || normalized.endsWith('.local')) return true
+  return isPrivateIpv4(normalized)
+}
+
+async function probeLanBackend(): Promise<boolean> {
+  if (typeof window === 'undefined') return false
+
+  const controller = new AbortController()
+  const timeout = window.setTimeout(() => controller.abort(), PROBE_TIMEOUT_MS)
+  try {
+    const response = await fetch(`${LAN_BACKEND_ORIGIN}/openapi.json`, {
+      method: 'GET',
+      cache: 'no-store',
+      signal: controller.signal,
+    })
+    if (!response.ok) return false
+
+    const data = (await response.json()) as { paths?: Record<string, unknown> }
+    const paths = data.paths
+    if (!paths || typeof paths !== 'object') return false
+
+    return EXPECTED_OPENAPI_PATHS.every((path) =>
+      Object.prototype.hasOwnProperty.call(paths, path),
+    )
+  } catch {
+    return false
+  } finally {
+    window.clearTimeout(timeout)
+  }
+}
+
+async function detectApiBaseUrl(): Promise<string> {
+  if (ENV_API_BASE_URL) return ENV_API_BASE_URL
+  if (typeof window === 'undefined') return PUBLIC_API_BASE_URL
+
+  if (!isLanHostname(window.location.hostname)) {
+    return PUBLIC_API_BASE_URL
+  }
+
+  const canUseLan = await probeLanBackend()
+  return canUseLan ? LAN_API_BASE_URL : PUBLIC_API_BASE_URL
+}
+
+function isLikelyNetworkError(error: unknown): boolean {
+  return error instanceof TypeError || (error instanceof DOMException && error.name === 'AbortError')
+}
+
+export async function getApiBaseUrl(): Promise<string> {
+  if (detectedApiBaseUrl) return detectedApiBaseUrl
+  if (!detectPromise) {
+    detectPromise = detectApiBaseUrl()
+      .then((url) => {
+        detectedApiBaseUrl = url
+        return url
+      })
+      .finally(() => {
+        detectPromise = null
+      })
+  }
+  return detectPromise
+}
+
+export async function fetchApi(path: string, init?: RequestInit): Promise<Response> {
+  const apiBaseUrl = await getApiBaseUrl()
+  const requestUrl = buildUrl(apiBaseUrl, path)
+
+  try {
+    return await fetch(requestUrl, init)
+  } catch (error) {
+    if (!ENV_API_BASE_URL && apiBaseUrl === LAN_API_BASE_URL && isLikelyNetworkError(error)) {
+      detectedApiBaseUrl = PUBLIC_API_BASE_URL
+      return fetch(buildUrl(PUBLIC_API_BASE_URL, path), init)
+    }
+    throw error
+  }
+}
diff --git a/frontend/src/views/RevisionsView.vue b/frontend/src/views/RevisionsView.vue
index 676ac2e..0263cc6 100644
--- a/frontend/src/views/RevisionsView.vue
+++ b/frontend/src/views/RevisionsView.vue
@@ -34,7 +34,6 @@ const platformIconMap: Record<string, string> = {
   抖音热榜: 'fa-brands fa-tiktok',
   抖音: 'fa-brands fa-tiktok',
   B站热搜: 'fa-brands fa-bilibili',
-  'B站热搜': 'fa-brands fa-bilibili',
   'bilibili 热搜': 'fa-brands fa-bilibili',
   华尔街见闻: 'fa-solid fa-chart-line',
   澎湃新闻: 'fa-solid fa-water',