diff --git a/apps/ui-admin/src/App.vue b/apps/ui-admin/src/App.vue
index 40165aa53..55130861e 100644
--- a/apps/ui-admin/src/App.vue
+++ b/apps/ui-admin/src/App.vue
@@ -52,23 +52,23 @@ onMounted(async () => {
 </script>
 
 <template>
-  <div class="min-h-screen bg-[#f7f8fa] text-[#171717]">
+  <div class="min-h-screen bg-[#f7f8fa] text-[#171717] dark:bg-neutral-950 dark:text-neutral-100">
     <div v-if="loading" class="grid min-h-screen place-items-center">
-      <div class="flex items-center gap-3 text-sm text-neutral-500">
+      <div class="flex items-center gap-3 text-sm text-neutral-500 dark:text-neutral-400">
         <span class="i-lucide-loader-2 animate-spin text-lg" />
         Loading admin session
       </div>
     </div>
 
     <div v-else-if="accessError" class="grid min-h-screen place-items-center px-6">
-      <section class="max-w-md w-full border border-neutral-200 rounded-lg bg-white p-6 shadow-sm">
+      <section class="max-w-md w-full border border-neutral-200 rounded-lg bg-white p-6 shadow-sm dark:border-neutral-800 dark:bg-neutral-900">
         <div class="mb-4 h-10 w-10 flex items-center justify-center rounded-lg bg-red-50 text-red-600">
           <span class="i-lucide-shield-alert text-xl" />
         </div>
         <h1 class="text-xl font-semibold">
           Admin access required
         </h1>
-        <p class="mt-2 text-sm text-neutral-500">
+        <p class="mt-2 text-sm text-neutral-500 dark:text-neutral-400">
           {{ accessError }}
         </p>
         <a class="mt-5 h-9 inline-flex items-center gap-2 rounded-md bg-emerald-600 px-3 text-sm text-white" :href="signInUrl()">
@@ -88,7 +88,7 @@ onMounted(async () => {
             <div class="truncate text-sm font-semibold">
               AIRI Admin
             </div>
-            <div class="truncate text-xs text-neutral-500">
+            <div class="truncate text-xs text-neutral-500 dark:text-neutral-400">
               Operations
             </div>
           </div>
@@ -132,8 +132,8 @@ onMounted(async () => {
       <main class="admin-main">
         <header class="admin-topbar">
           <div class="flex items-center gap-3">
-            <span class="i-lucide-panel-left text-neutral-500" />
-            <div class="h-5 w-px bg-neutral-200" />
+            <span class="i-lucide-panel-left text-neutral-500 dark:text-neutral-400" />
+            <div class="h-5 w-px bg-neutral-200 dark:bg-neutral-800" />
             <h1 class="text-sm font-semibold">
               {{ currentTitle }}
             </h1>
diff --git a/apps/ui-admin/src/components/llm-router/RouterAdvancedJsonPanel.vue b/apps/ui-admin/src/components/llm-router/RouterAdvancedJsonPanel.vue
index 2022f67b8..f76b1f88b 100644
--- a/apps/ui-admin/src/components/llm-router/RouterAdvancedJsonPanel.vue
+++ b/apps/ui-admin/src/components/llm-router/RouterAdvancedJsonPanel.vue
@@ -19,16 +19,16 @@ const json = defineModel<string>({ required: true })
 
 <template>
   <section :class="['panel', 'overflow-hidden']">
-    <div :class="['flex', 'items-start', 'justify-between', 'gap-3', 'border-b', 'border-neutral-200', 'px-4', 'py-3']">
+    <div :class="['flex', 'items-start', 'justify-between', 'gap-3', 'border-b', 'border-neutral-200', 'px-4', 'py-3', 'dark:border-neutral-800']">
       <div>
         <h3 :class="['text-sm', 'font-semibold']">
           Advanced JSON
         </h3>
-        <p :class="['mt-1', 'text-xs', 'text-neutral-500']">
+        <p :class="['mt-1', 'text-xs', 'text-neutral-500', 'dark:text-neutral-400']">
           Escape hatch for auditing or unsupported future fields.
         </p>
       </div>
-      <span :class="['i-lucide-code-2', 'text-neutral-500']" />
+      <span :class="['i-lucide-code-2', 'text-neutral-500', 'dark:text-neutral-400']" />
     </div>
 
     <div :class="['space-y-4', 'p-4']">
diff --git a/apps/ui-admin/src/components/llm-router/RouterDefaultsEditor.vue b/apps/ui-admin/src/components/llm-router/RouterDefaultsEditor.vue
index 4b6f3af7e..c2e22bdd8 100644
--- a/apps/ui-admin/src/components/llm-router/RouterDefaultsEditor.vue
+++ b/apps/ui-admin/src/components/llm-router/RouterDefaultsEditor.vue
@@ -9,13 +9,13 @@ const defaults = defineModel<RouterDefaultsDraft>({ required: true })
 </script>
 
 <template>
-  <section :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-white', 'p-4']">
+  <section :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-white', 'p-4', 'dark:border-neutral-800', 'dark:bg-neutral-900']">
     <div :class="['mb-4', 'flex', 'items-start', 'justify-between', 'gap-3']">
       <div>
         <h3 :class="['text-sm', 'font-semibold']">
           Defaults
         </h3>
-        <p :class="['mt-1', 'text-xs', 'text-neutral-500']">
+        <p :class="['mt-1', 'text-xs', 'text-neutral-500', 'dark:text-neutral-400']">
           Writes default model aliases alongside provider slices when filled.
         </p>
       </div>
@@ -44,7 +44,7 @@ const defaults = defineModel<RouterDefaultsDraft>({ required: true })
           <div :class="['text-sm', 'font-medium']">
             Recommended voices
           </div>
-          <div :class="['text-xs', 'text-neutral-500']">
+          <div :class="['text-xs', 'text-neutral-500', 'dark:text-neutral-400']">
             JSON object written to DEFAULT_TTS_VOICES.
           </div>
         </div>
diff --git a/apps/ui-admin/src/components/llm-router/RouterModeControl.vue b/apps/ui-admin/src/components/llm-router/RouterModeControl.vue
index b12b07764..af336e76b 100644
--- a/apps/ui-admin/src/components/llm-router/RouterModeControl.vue
+++ b/apps/ui-admin/src/components/llm-router/RouterModeControl.vue
@@ -7,13 +7,13 @@ const mode = defineModel<RouterConfigMode>({ required: true })
 </script>
 
 <template>
-  <section :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-white', 'p-4']">
+  <section :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-white', 'p-4', 'dark:border-neutral-800', 'dark:bg-neutral-900']">
     <div :class="['flex', 'items-start', 'justify-between', 'gap-3']">
       <div>
         <h3 :class="['text-sm', 'font-semibold']">
           Write Mode
         </h3>
-        <p :class="['mt-1', 'text-xs', 'text-neutral-500']">
+        <p :class="['mt-1', 'text-xs', 'text-neutral-500', 'dark:text-neutral-400']">
           Merge keeps untouched router models. Reset replaces the router model tree with this request.
         </p>
       </div>
diff --git a/apps/ui-admin/src/components/llm-router/RouterPreviewPanel.vue b/apps/ui-admin/src/components/llm-router/RouterPreviewPanel.vue
index 22d2a910f..714c98e5f 100644
--- a/apps/ui-admin/src/components/llm-router/RouterPreviewPanel.vue
+++ b/apps/ui-admin/src/components/llm-router/RouterPreviewPanel.vue
@@ -18,22 +18,22 @@ function formatJson(value: unknown): string {
 
 <template>
   <section :class="['panel', 'overflow-hidden']">
-    <div :class="['border-b', 'border-neutral-200', 'px-4', 'py-3', 'text-sm', 'font-semibold']">
+    <div :class="['border-b', 'border-neutral-200', 'px-4', 'py-3', 'text-sm', 'font-semibold', 'dark:border-neutral-800']">
       {{ title }}
     </div>
 
     <div v-if="result" :class="['space-y-4', 'p-4']">
       <div :class="['grid', 'gap-3', 'text-xs', 'sm:grid-cols-2']">
-        <div :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-neutral-50', 'p-3']">
-          <div :class="['text-neutral-500']">
+        <div :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-neutral-50', 'p-3', 'dark:border-neutral-800', 'dark:bg-neutral-950']">
+          <div :class="['text-neutral-500', 'dark:text-neutral-400']">
             Slices
           </div>
           <div :class="['mt-1', 'text-lg', 'font-semibold']">
             {{ applied.length }}
           </div>
         </div>
-        <div :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-neutral-50', 'p-3']">
-          <div :class="['text-neutral-500']">
+        <div :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-neutral-50', 'p-3', 'dark:border-neutral-800', 'dark:bg-neutral-950']">
+          <div :class="['text-neutral-500', 'dark:text-neutral-400']">
             Invalidated keys
           </div>
           <div :class="['mt-1', 'text-lg', 'font-semibold']">
@@ -43,7 +43,7 @@ function formatJson(value: unknown): string {
       </div>
 
       <div v-if="applied.length" :class="['space-y-2']">
-        <div :class="['text-xs', 'font-semibold', 'uppercase', 'text-neutral-500']">
+        <div :class="['text-xs', 'font-semibold', 'uppercase', 'text-neutral-500', 'dark:text-neutral-400']">
           Applied
         </div>
         <div :class="['flex', 'flex-wrap', 'gap-2']">
@@ -59,7 +59,7 @@ function formatJson(value: unknown): string {
       </div>
 
       <div v-if="invalidatedKeys.length" :class="['space-y-2']">
-        <div :class="['text-xs', 'font-semibold', 'uppercase', 'text-neutral-500']">
+        <div :class="['text-xs', 'font-semibold', 'uppercase', 'text-neutral-500', 'dark:text-neutral-400']">
           Keys
         </div>
         <div :class="['flex', 'flex-wrap', 'gap-2']">
diff --git a/apps/ui-admin/src/components/llm-router/RouterSliceEditor.vue b/apps/ui-admin/src/components/llm-router/RouterSliceEditor.vue
index 49888dd35..ab5534c89 100644
--- a/apps/ui-admin/src/components/llm-router/RouterSliceEditor.vue
+++ b/apps/ui-admin/src/components/llm-router/RouterSliceEditor.vue
@@ -69,13 +69,13 @@ const streamingKeyPlaceholder = computed(() => {
 </script>
 
 <template>
-  <section :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-white', 'p-4']">
+  <section :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-white', 'p-4', 'dark:border-neutral-800', 'dark:bg-neutral-900']">
     <div :class="['mb-4', 'flex', 'flex-col', 'gap-3', 'md:flex-row', 'md:items-start', 'md:justify-between']">
       <div :class="['min-w-0']">
         <h3 :class="['truncate', 'text-sm', 'font-semibold']">
           {{ index }}. {{ title }}
         </h3>
-        <p :class="['mt-1', 'text-xs', 'text-neutral-500']">
+        <p :class="['mt-1', 'text-xs', 'text-neutral-500', 'dark:text-neutral-400']">
           {{ slice.kind }}
         </p>
       </div>
@@ -122,11 +122,11 @@ const streamingKeyPlaceholder = computed(() => {
     <div v-else :class="['space-y-4']">
       <FieldInput v-model="slice.restBaseURL" input-class="font-mono text-xs" label="REST base URL" placeholder="http://airi-unspeech.railway.internal:5933" required />
 
-      <label :class="['flex', 'items-start', 'gap-3', 'rounded-lg', 'border', 'border-neutral-200', 'bg-neutral-50', 'p-3']">
+      <label :class="['flex', 'items-start', 'gap-3', 'rounded-lg', 'border', 'border-neutral-200', 'bg-neutral-50', 'p-3', 'dark:border-neutral-800', 'dark:bg-neutral-950']">
         <input v-model="slice.streamingEnabled" :class="['mt-1']" type="checkbox">
         <span>
           <span :class="['block', 'text-sm', 'font-medium']">Enable streaming upstream</span>
-          <span :class="['block', 'text-xs', 'text-neutral-500']">Writes UNSPEECH_UPSTREAM.streaming for WebSocket TTS.</span>
+          <span :class="['block', 'text-xs', 'text-neutral-500', 'dark:text-neutral-400']">Writes UNSPEECH_UPSTREAM.streaming for WebSocket TTS.</span>
         </span>
       </label>
 
diff --git a/apps/ui-admin/src/modules/api.test.ts b/apps/ui-admin/src/modules/api.test.ts
new file mode 100644
index 000000000..25aa69ce8
--- /dev/null
+++ b/apps/ui-admin/src/modules/api.test.ts
@@ -0,0 +1,23 @@
+import { describe, expect, it } from 'vitest'
+
+import { buildAdminSignInUrl } from './api'
+
+describe('ui-admin API URL helpers', () => {
+  it('builds sign-in URLs with the absolute admin return URL', () => {
+    expect(buildAdminSignInUrl(
+      'http://127.0.0.1:3000',
+      'http://127.0.0.1:5178/llm-router?api_server_url=http%3A%2F%2F127.0.0.1%3A3000',
+    )).toBe(
+      'http://127.0.0.1:3000/auth/sign-in?redirect=http%3A%2F%2F127.0.0.1%3A5178%2Fllm-router%3Fapi_server_url%3Dhttp%253A%252F%252F127.0.0.1%253A3000',
+    )
+  })
+
+  it('builds local dev sign-in URLs on the local API origin', () => {
+    expect(buildAdminSignInUrl(
+      'http://localhost:3000',
+      'http://localhost:5178/',
+    )).toBe(
+      'http://localhost:3000/auth/sign-in?redirect=http%3A%2F%2Flocalhost%3A5178%2F',
+    )
+  })
+})
diff --git a/apps/ui-admin/src/modules/api.ts b/apps/ui-admin/src/modules/api.ts
index 6c8b640f3..9c4ccf6ea 100644
--- a/apps/ui-admin/src/modules/api.ts
+++ b/apps/ui-admin/src/modules/api.ts
@@ -209,12 +209,29 @@ export function apiServerUrl(): string {
   return getServerAdminBootstrapContext()?.apiServerUrl ?? defaultApiServerUrl()
 }
 
-export function signInUrl(): string {
-  const url = new URL('/auth/sign-in', apiServerUrl())
-  url.searchParams.set('redirect', `${window.location.pathname}${window.location.search}`)
+/**
+ * Builds an API-owned sign-in URL that returns to the exact admin page.
+ *
+ * Use when:
+ * - The standalone admin app needs to bounce through the API auth route.
+ * - The admin app may be hosted on a different origin than the auth UI.
+ *
+ * Expects:
+ * - `currentUrl` is the browser's absolute admin URL.
+ *
+ * Returns:
+ * - An API `/auth/sign-in` URL carrying an absolute trusted return target.
+ */
+export function buildAdminSignInUrl(apiServerUrl: string, currentUrl: string): string {
+  const url = new URL('/auth/sign-in', apiServerUrl)
+  url.searchParams.set('redirect', currentUrl)
   return url.toString()
 }
 
+export function signInUrl(): string {
+  return buildAdminSignInUrl(apiServerUrl(), window.location.href)
+}
+
 async function adminFetch<T>(path: string, init: RequestInit = {}): Promise<T> {
   const endpoint = new URL(`/api/admin${path}`, apiServerUrl())
   return fetchJson<T>(endpoint, init)
diff --git a/apps/ui-admin/src/modules/server-admin-context.test.ts b/apps/ui-admin/src/modules/server-admin-context.test.ts
index 46d7af1d6..5d7fe8c06 100644
--- a/apps/ui-admin/src/modules/server-admin-context.test.ts
+++ b/apps/ui-admin/src/modules/server-admin-context.test.ts
@@ -2,7 +2,7 @@
 
 import { describe, expect, it } from 'vitest'
 
-import { getServerAdminBootstrapContext, resolveStandaloneServerAdminContext } from './server-admin-context'
+import { defaultStandaloneApiServerUrl, getServerAdminBootstrapContext, resolveStandaloneServerAdminContext } from './server-admin-context'
 
 describe('ui-admin bootstrap context', () => {
   it('uses the trusted API server origin carried by standalone server redirects', () => {
@@ -26,6 +26,15 @@ describe('ui-admin bootstrap context', () => {
     )?.apiServerUrl).toBe('http://127.0.0.1:3000')
   })
 
+  it('defaults local standalone dev UI origins to the local API port', () => {
+    expect(defaultStandaloneApiServerUrl('http://localhost:5178')).toBe('http://localhost:3000')
+    expect(defaultStandaloneApiServerUrl('http://127.0.0.1:5178')).toBe('http://127.0.0.1:3000')
+  })
+
+  it('keeps non-local standalone origins unchanged without redirect context', () => {
+    expect(defaultStandaloneApiServerUrl('https://admin.airi.build')).toBe('https://admin.airi.build')
+  })
+
   it('falls back to the standalone query context when the static placeholder script is still present', () => {
     document.body.innerHTML = '<script id="airi-server-admin-context" type="application/json">__AIRI_SERVER_ADMIN_CONTEXT__</script>'
     window.history.replaceState(
diff --git a/apps/ui-admin/src/modules/server-admin-context.ts b/apps/ui-admin/src/modules/server-admin-context.ts
index 74d52756b..294bd711b 100644
--- a/apps/ui-admin/src/modules/server-admin-context.ts
+++ b/apps/ui-admin/src/modules/server-admin-context.ts
@@ -45,7 +45,28 @@ export function getServerAdminBootstrapContext(): ServerAdminBootstrapContext |
 }
 
 export function defaultApiServerUrl(): string {
-  return import.meta.env.VITE_SERVER_URL || window.location.origin
+  return import.meta.env.VITE_SERVER_URL || defaultStandaloneApiServerUrl(window.location.origin)
+}
+
+/**
+ * Resolves the API origin for a standalone admin UI without redirect context.
+ *
+ * Before:
+ * - "http://localhost:5178"
+ *
+ * After:
+ * - "http://localhost:3000"
+ */
+export function defaultStandaloneApiServerUrl(currentOrigin: string): string {
+  const origin = new URL(currentOrigin).origin
+
+  if (TRUSTED_LOCAL_API_SERVER_ORIGIN_PATTERNS.some(pattern => pattern.test(origin))) {
+    const url = new URL(origin)
+    url.port = '3000'
+    return url.origin
+  }
+
+  return origin
 }
 
 /**
diff --git a/apps/ui-admin/src/pages/LlmRouterPage.vue b/apps/ui-admin/src/pages/LlmRouterPage.vue
index ad7ddc3c6..02be39614 100644
--- a/apps/ui-admin/src/pages/LlmRouterPage.vue
+++ b/apps/ui-admin/src/pages/LlmRouterPage.vue
@@ -250,12 +250,12 @@ function isCurrentConfigResponse(value: AdminRouterConfigCurrent | null): value
 <template>
   <div :class="['grid', 'gap-5', 'xl:grid-cols-[minmax(0,1fr)_420px]']">
     <section :class="['panel', 'overflow-hidden']">
-      <div :class="['flex', 'flex-col', 'gap-3', 'border-b', 'border-neutral-200', 'px-5', 'py-4', 'md:flex-row', 'md:items-center', 'md:justify-between']">
+      <div :class="['flex', 'flex-col', 'gap-3', 'border-b', 'border-neutral-200', 'px-5', 'py-4', 'md:flex-row', 'md:items-center', 'md:justify-between', 'dark:border-neutral-800']">
         <div>
           <h2 :class="['text-sm', 'font-semibold']">
             Router Config Form
           </h2>
-          <p :class="['mt-1', 'text-sm', 'text-neutral-500']">
+          <p :class="['mt-1', 'text-sm', 'text-neutral-500', 'dark:text-neutral-400']">
             Builds LLM_ROUTER_CONFIG, UNSPEECH_UPSTREAM, and default model aliases without hand-written JSON.
           </p>
         </div>
@@ -266,13 +266,13 @@ function isCurrentConfigResponse(value: AdminRouterConfigCurrent | null): value
       </div>
 
       <form :class="['space-y-5', 'p-5']" @submit.prevent="previewConfig">
-        <section :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-white', 'p-4']">
+        <section :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-white', 'p-4', 'dark:border-neutral-800', 'dark:bg-neutral-900']">
           <div :class="['flex', 'flex-col', 'gap-3', 'md:flex-row', 'md:items-center', 'md:justify-between']">
             <div>
               <h3 :class="['text-sm', 'font-semibold']">
                 Current Config
               </h3>
-              <p :class="['mt-1', 'text-xs', currentError ? 'text-red-600' : 'text-neutral-500']">
+              <p :class="['mt-1', 'text-xs', currentError ? 'text-red-600 dark:text-red-400' : 'text-neutral-500 dark:text-neutral-400']">
                 {{ currentError ?? currentStatusLabel }}
               </p>
             </div>
@@ -293,13 +293,13 @@ function isCurrentConfigResponse(value: AdminRouterConfigCurrent | null): value
         <RouterModeControl v-model="form.mode" />
         <RouterDefaultsEditor v-model="form.defaults" />
 
-        <section :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-white']">
-          <div :class="['border-b', 'border-neutral-200', 'p-4']">
+        <section :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-white', 'dark:border-neutral-800', 'dark:bg-neutral-900']">
+          <div :class="['border-b', 'border-neutral-200', 'p-4', 'dark:border-neutral-800']">
             <div>
               <h3 :class="['text-sm', 'font-semibold']">
                 Provider configuration
               </h3>
-              <p :class="['mt-1', 'text-xs', 'text-neutral-500']">
+              <p :class="['mt-1', 'text-xs', 'text-neutral-500', 'dark:text-neutral-400']">
                 LLM and TTS providers are edited separately, then applied as one router config request.
               </p>
             </div>
@@ -308,7 +308,7 @@ function isCurrentConfigResponse(value: AdminRouterConfigCurrent | null): value
           <div :class="['flex', 'flex-col', 'gap-4', 'p-4']">
             <div :class="['flex', 'flex-col', 'gap-3', 'lg:flex-row', 'lg:items-end', 'lg:justify-between']">
               <div
-                :class="['inline-grid', 'w-full', 'grid-cols-2', 'rounded-lg', 'border', 'border-neutral-200', 'bg-neutral-50', 'p-1', 'sm:w-auto']"
+                :class="['inline-grid', 'w-full', 'grid-cols-2', 'rounded-lg', 'border', 'border-neutral-200', 'bg-neutral-50', 'p-1', 'sm:w-auto', 'dark:border-neutral-800', 'dark:bg-neutral-950']"
                 role="tablist"
               >
                 <button
@@ -318,15 +318,15 @@ function isCurrentConfigResponse(value: AdminRouterConfigCurrent | null): value
                   :class="[
                     'h-9 rounded-md px-4 text-sm font-medium transition-colors whitespace-nowrap',
                     activeProviderTab === tab.value
-                      ? 'bg-white text-primary-700 shadow-sm ring-1 ring-primary-200'
-                      : 'text-neutral-500 hover:text-neutral-900',
+                      ? 'bg-white text-primary-700 shadow-sm ring-1 ring-primary-200 dark:bg-neutral-900 dark:text-primary-300 dark:ring-primary-800'
+                      : 'text-neutral-500 hover:text-neutral-900 dark:text-neutral-400 dark:hover:text-neutral-200',
                   ]"
                   role="tab"
                   type="button"
                   @click="selectProviderTab(tab.value)"
                 >
                   {{ tab.label }}
-                  <span :class="['ml-1', 'text-xs', activeProviderTab === tab.value ? 'text-neutral-500' : 'text-neutral-400']">
+                  <span :class="['ml-1', 'text-xs', activeProviderTab === tab.value ? 'text-neutral-500 dark:text-neutral-400' : 'text-neutral-400 dark:text-neutral-500']">
                     {{ tab.count }}
                   </span>
                 </button>
@@ -344,8 +344,8 @@ function isCurrentConfigResponse(value: AdminRouterConfigCurrent | null): value
               </div>
             </div>
 
-            <div :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-neutral-50/60', 'px-3', 'py-2', 'text-xs', 'text-neutral-600']">
-              <span :class="['font-medium', 'text-neutral-900']">{{ activeProviderTab === 'llm' ? 'LLM' : 'TTS' }}</span>
+            <div :class="['rounded-lg', 'border', 'border-neutral-200', 'bg-neutral-50/60', 'px-3', 'py-2', 'text-xs', 'text-neutral-600', 'dark:border-neutral-800', 'dark:bg-neutral-950/60', 'dark:text-neutral-300']">
+              <span :class="['font-medium', 'text-neutral-900', 'dark:text-neutral-100']">{{ activeProviderTab === 'llm' ? 'LLM' : 'TTS' }}</span>
               <span v-if="activeProviderTab === 'llm'">
                 config writes chat model aliases under LLM_ROUTER_CONFIG.
               </span>
@@ -364,11 +364,11 @@ function isCurrentConfigResponse(value: AdminRouterConfigCurrent | null): value
                 @remove="removeSlice(item.index)"
               />
             </div>
-            <div v-else :class="['empty-state', 'min-h-40', 'rounded-lg', 'border', 'border-dashed', 'border-neutral-200', 'bg-white']">
+            <div v-else :class="['empty-state', 'min-h-40', 'rounded-lg', 'border', 'border-dashed', 'border-neutral-200', 'bg-white', 'dark:border-neutral-800', 'dark:bg-neutral-900']">
               No {{ activeProviderTab === 'llm' ? 'LLM' : 'TTS' }} provider slices
             </div>
           </div>
-          <div :class="['border-t', 'border-neutral-200', 'px-4', 'py-3', 'text-xs', 'text-neutral-500']">
+          <div :class="['border-t', 'border-neutral-200', 'px-4', 'py-3', 'text-xs', 'text-neutral-500', 'dark:border-neutral-800', 'dark:text-neutral-400']">
             UnSpeech is limited to one TTS slice per request.
           </div>
         </section>
@@ -381,26 +381,26 @@ function isCurrentConfigResponse(value: AdminRouterConfigCurrent | null): value
           </ul>
         </Callout>
 
-        <div :class="['flex', 'flex-col', 'gap-3', 'border-t', 'border-neutral-200', 'pt-4', 'md:flex-row', 'md:items-center', 'md:justify-between']">
-          <div :class="['grid', 'gap-2', 'text-xs', 'text-neutral-600', 'sm:grid-cols-5']">
+        <div :class="['flex', 'flex-col', 'gap-3', 'border-t', 'border-neutral-200', 'pt-4', 'md:flex-row', 'md:items-center', 'md:justify-between', 'dark:border-neutral-800']">
+          <div :class="['grid', 'gap-2', 'text-xs', 'text-neutral-600', 'sm:grid-cols-5', 'dark:text-neutral-400']">
             <div>
-              <span :class="['block', 'font-semibold', 'text-neutral-900']">{{ pendingSummary.slices }}</span>
+              <span :class="['block', 'font-semibold', 'text-neutral-900', 'dark:text-neutral-100']">{{ pendingSummary.slices }}</span>
               slices
             </div>
             <div>
-              <span :class="['block', 'font-semibold', 'text-neutral-900']">{{ pendingSummary.llmSlices }}</span>
+              <span :class="['block', 'font-semibold', 'text-neutral-900', 'dark:text-neutral-100']">{{ pendingSummary.llmSlices }}</span>
               LLM
             </div>
             <div>
-              <span :class="['block', 'font-semibold', 'text-neutral-900']">{{ pendingSummary.ttsSlices }}</span>
+              <span :class="['block', 'font-semibold', 'text-neutral-900', 'dark:text-neutral-100']">{{ pendingSummary.ttsSlices }}</span>
               TTS
             </div>
             <div>
-              <span :class="['block', 'font-semibold', 'text-neutral-900']">{{ pendingSummary.unspeech ? 'yes' : 'no' }}</span>
+              <span :class="['block', 'font-semibold', 'text-neutral-900', 'dark:text-neutral-100']">{{ pendingSummary.unspeech ? 'yes' : 'no' }}</span>
               unspeech
             </div>
             <div>
-              <span :class="['block', 'font-semibold', 'text-neutral-900']">{{ pendingSummary.defaults }}</span>
+              <span :class="['block', 'font-semibold', 'text-neutral-900', 'dark:text-neutral-100']">{{ pendingSummary.defaults }}</span>
               defaults
             </div>
           </div>
diff --git a/apps/ui-admin/src/styles/main.css b/apps/ui-admin/src/styles/main.css
index 2d5f622b7..52957e0f3 100644
--- a/apps/ui-admin/src/styles/main.css
+++ b/apps/ui-admin/src/styles/main.css
@@ -2,6 +2,7 @@
 
 :root {
   --admin-accent: #059669;
+  color-scheme: light;
 }
 
 html,
@@ -13,9 +14,19 @@ body,
 
 body {
   background: #f7f8fa;
+  color: #18181b;
   font-feature-settings: "cv02", "cv03", "cv04", "cv11";
 }
 
+html.dark {
+  color-scheme: dark;
+}
+
+html.dark body {
+  background: #09090b;
+  color: #f4f4f5;
+}
+
 button,
 input,
 textarea,
@@ -52,10 +63,19 @@ select {
   padding: 18px 14px;
 }
 
+html.dark .admin-sidebar {
+  background: #111113;
+  border-color: #27272a;
+}
+
 .admin-main {
   min-width: 0;
 }
 
+html.dark .admin-main {
+  background: #09090b;
+}
+
 .admin-topbar {
   align-items: center;
   background: rgba(255, 255, 255, 0.86);
@@ -69,6 +89,11 @@ select {
   z-index: 10;
 }
 
+html.dark .admin-topbar {
+  background: rgba(9, 9, 11, 0.88);
+  border-color: #27272a;
+}
+
 .admin-content {
   padding: 22px;
 }
@@ -101,16 +126,30 @@ select {
   text-decoration: none;
 }
 
+html.dark .nav-item {
+  color: #d4d4d8;
+}
+
 .nav-item:hover {
   background: #e9ecef;
 }
 
+html.dark .nav-item:hover {
+  background: #27272a;
+}
+
 .nav-item-active {
   background: #ffffff;
   box-shadow: 0 1px 2px rgba(15, 23, 42, 0.08);
   font-weight: 600;
 }
 
+html.dark .nav-item-active {
+  background: #18181b;
+  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.35);
+  color: #f4f4f5;
+}
+
 .panel {
   background: white;
   border: 1px solid #e5e7eb;
@@ -118,6 +157,12 @@ select {
   box-shadow: 0 1px 2px rgba(15, 23, 42, 0.04);
 }
 
+html.dark .panel {
+  background: #18181b;
+  border-color: #27272a;
+  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
+}
+
 .metric-card {
   background: linear-gradient(180deg, #ffffff 0%, #f8fbfa 100%);
   border: 1px solid #e5e7eb;
@@ -126,6 +171,11 @@ select {
   padding: 20px;
 }
 
+html.dark .metric-card {
+  background: linear-gradient(180deg, #18181b 0%, #111113 100%);
+  border-color: #27272a;
+}
+
 .field {
   background: #fff;
   border: 1px solid #dfe3e8;
@@ -137,6 +187,12 @@ select {
   width: 100%;
 }
 
+html.dark .field {
+  background: #09090b;
+  border-color: #27272a;
+  color: #f4f4f5;
+}
+
 .field:focus,
 .textarea:focus {
   border-color: #10b981;
@@ -155,6 +211,12 @@ select {
   width: 100%;
 }
 
+html.dark .textarea {
+  background: #09090b;
+  border-color: #27272a;
+  color: #f4f4f5;
+}
+
 .btn {
   align-items: center;
   border: 1px solid #dfe3e8;
@@ -179,12 +241,24 @@ select {
   color: #27272a;
 }
 
+html.dark .btn-secondary {
+  background: #18181b;
+  border-color: #3f3f46;
+  color: #f4f4f5;
+}
+
 .btn-danger {
   background: #fff;
   border-color: #fecaca;
   color: #b91c1c;
 }
 
+html.dark .btn-danger {
+  background: #18181b;
+  border-color: #7f1d1d;
+  color: #fecaca;
+}
+
 .table {
   border-collapse: collapse;
   width: 100%;
@@ -198,6 +272,11 @@ select {
   vertical-align: middle;
 }
 
+html.dark .table th,
+html.dark .table td {
+  border-color: #27272a;
+}
+
 .table th {
   background: #f8fafc;
   color: #52525b;
@@ -205,11 +284,20 @@ select {
   font-weight: 600;
 }
 
+html.dark .table th {
+  background: #111113;
+  color: #a1a1aa;
+}
+
 .table td {
   color: #27272a;
   font-size: 13px;
 }
 
+html.dark .table td {
+  color: #e4e4e7;
+}
+
 .badge {
   align-items: center;
   border: 1px solid #e5e7eb;
@@ -222,18 +310,35 @@ select {
   padding: 0 8px;
 }
 
+html.dark .badge {
+  border-color: #3f3f46;
+  color: #e4e4e7;
+}
+
 .badge-green {
   background: #ecfdf5;
   border-color: #bbf7d0;
   color: #047857;
 }
 
+html.dark .badge-green {
+  background: rgba(6, 78, 59, 0.5);
+  border-color: rgba(52, 211, 153, 0.28);
+  color: #6ee7b7;
+}
+
 .badge-amber {
   background: #fffbeb;
   border-color: #fde68a;
   color: #b45309;
 }
 
+html.dark .badge-amber {
+  background: rgba(120, 53, 15, 0.45);
+  border-color: rgba(251, 191, 36, 0.3);
+  color: #fcd34d;
+}
+
 .empty-state {
   align-items: center;
   color: #71717a;
@@ -245,6 +350,114 @@ select {
   min-height: 180px;
 }
 
+html.dark .empty-state {
+  color: #a1a1aa;
+}
+
+@media (prefers-color-scheme: dark) {
+  :root {
+    color-scheme: dark;
+  }
+
+  body {
+    background: #09090b;
+    color: #f4f4f5;
+  }
+
+  .admin-sidebar {
+    background: #111113;
+    border-color: #27272a;
+  }
+
+  .admin-main {
+    background: #09090b;
+  }
+
+  .admin-topbar {
+    background: rgba(9, 9, 11, 0.88);
+    border-color: #27272a;
+  }
+
+  .nav-item {
+    color: #d4d4d8;
+  }
+
+  .nav-item:hover {
+    background: #27272a;
+  }
+
+  .nav-item-active {
+    background: #18181b;
+    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.35);
+    color: #f4f4f5;
+  }
+
+  .panel {
+    background: #18181b;
+    border-color: #27272a;
+    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
+  }
+
+  .metric-card {
+    background: linear-gradient(180deg, #18181b 0%, #111113 100%);
+    border-color: #27272a;
+  }
+
+  .field,
+  .textarea {
+    background: #09090b;
+    border-color: #27272a;
+    color: #f4f4f5;
+  }
+
+  .btn-secondary {
+    background: #18181b;
+    border-color: #3f3f46;
+    color: #f4f4f5;
+  }
+
+  .btn-danger {
+    background: #18181b;
+    border-color: #7f1d1d;
+    color: #fecaca;
+  }
+
+  .table th,
+  .table td {
+    border-color: #27272a;
+  }
+
+  .table th {
+    background: #111113;
+    color: #a1a1aa;
+  }
+
+  .table td {
+    color: #e4e4e7;
+  }
+
+  .badge {
+    border-color: #3f3f46;
+    color: #e4e4e7;
+  }
+
+  .badge-green {
+    background: rgba(6, 78, 59, 0.5);
+    border-color: rgba(52, 211, 153, 0.28);
+    color: #6ee7b7;
+  }
+
+  .badge-amber {
+    background: rgba(120, 53, 15, 0.45);
+    border-color: rgba(251, 191, 36, 0.3);
+    color: #fcd34d;
+  }
+
+  .empty-state {
+    color: #a1a1aa;
+  }
+}
+
 @media (max-width: 900px) {
   .admin-shell {
     grid-template-columns: 1fr;
@@ -256,7 +469,17 @@ select {
     min-height: auto;
   }
 
+  html.dark .admin-sidebar {
+    border-bottom-color: #27272a;
+  }
+
   .admin-content {
     padding: 16px;
   }
 }
+
+@media (max-width: 900px) and (prefers-color-scheme: dark) {
+  .admin-sidebar {
+    border-bottom-color: #27272a;
+  }
+}
diff --git a/packages/ui/src/components/form/field/field-input.vue b/packages/ui/src/components/form/field/field-input.vue
index 47f57a992..71ab4fe5b 100644
--- a/packages/ui/src/components/form/field/field-input.vue
+++ b/packages/ui/src/components/form/field/field-input.vue
@@ -85,6 +85,7 @@ const modelValue = defineModel<T>({ required: false })
           'text-disabled:neutral-400 dark:text-disabled:neutral-600',
           'cursor-disabled:not-allowed',
           'w-full rounded-lg px-2 py-1 text-sm outline-none',
+          'text-neutral-900 dark:text-neutral-100 placeholder:text-neutral-400 dark:placeholder:text-neutral-500',
           'shadow-sm',
           'bg-neutral-50 dark:bg-neutral-950 focus:bg-neutral-50 dark:focus:bg-neutral-900',
         ]"
diff --git a/packages/ui/src/components/form/input/input.vue b/packages/ui/src/components/form/input/input.vue
index f19150a0f..d136a4f2c 100644
--- a/packages/ui/src/components/form/input/input.vue
+++ b/packages/ui/src/components/form/input/input.vue
@@ -40,6 +40,7 @@ const variantClasses: Record<InputVariant, Record<InputTheme, {
       default: [
         'w-full rounded-lg px-2 py-1 text-nowrap text-sm outline-none',
         'bg-neutral-50 dark:bg-neutral-950 focus:bg-neutral-50 dark:focus:bg-neutral-900',
+        'text-neutral-900 dark:text-neutral-100 placeholder:text-neutral-400 dark:placeholder:text-neutral-500',
         'focus:border-primary-300 dark:focus:border-primary-400/50 border-2 border-solid border-neutral-100 dark:border-neutral-900',
         'text-disabled:neutral-400 dark:text-disabled:neutral-600',
         'shadow-sm',
@@ -51,6 +52,7 @@ const variantClasses: Record<InputVariant, Record<InputTheme, {
       default: [
         'w-full rounded-lg px-2 py-1 text-nowrap text-sm outline-none',
         'bg-neutral-50 dark:bg-neutral-950 focus:bg-neutral-50 dark:focus:bg-neutral-900',
+        'text-neutral-900 dark:text-neutral-100 placeholder:text-neutral-400 dark:placeholder:text-neutral-500',
         'focus:border-primary-300 dark:focus:border-primary-400/50 border-2 border-solid border-neutral-100 dark:border-neutral-900',
         'text-disabled:neutral-400 dark:text-disabled:neutral-600',
         'shadow-sm',
@@ -62,6 +64,7 @@ const variantClasses: Record<InputVariant, Record<InputTheme, {
       default: [
         'w-full rounded-lg px-2 py-1 text-nowrap text-sm outline-none',
         'bg-neutral-100 dark:bg-neutral-800 focus:bg-neutral-50 dark:focus:bg-neutral-950',
+        'text-neutral-900 dark:text-neutral-100 placeholder:text-neutral-400 dark:placeholder:text-neutral-500',
         'focus:border-primary-500/30 dark:focus:border-primary-400/50 border-2 border-solid border-neutral-500/5 dark:border-neutral-700/40',
         'text-disabled:neutral-400 dark:text-disabled:neutral-600',
       ],
diff --git a/packages/ui/src/components/form/textarea/textarea.vue b/packages/ui/src/components/form/textarea/textarea.vue
index 3e67794a3..c0832948d 100644
--- a/packages/ui/src/components/form/textarea/textarea.vue
+++ b/packages/ui/src/components/form/textarea/textarea.vue
@@ -13,6 +13,7 @@ const modelValue = defineModel<string>({ default: '' })
       'text-disabled:neutral-400 dark:text-disabled:neutral-600',
       'cursor-disabled:not-allowed',
       'w-full rounded-lg px-2 py-1 text-nowrap text-sm outline-none',
+      'text-neutral-900 dark:text-neutral-100 placeholder:text-neutral-400 dark:placeholder:text-neutral-500',
       'shadow-sm',
       'bg-neutral-50 dark:bg-neutral-950 focus:bg-neutral-50 dark:focus:bg-neutral-900',
     ]"
diff --git a/packages/ui/src/components/misc/button.vue b/packages/ui/src/components/misc/button.vue
index ac2142f71..5b3a81c74 100644
--- a/packages/ui/src/components/misc/button.vue
+++ b/packages/ui/src/components/misc/button.vue
@@ -154,7 +154,7 @@ const baseClasses = computed(() => {
   const theme = variant[props.theme] || variant.default
 
   return [
-    'font-medium outline-none',
+    'font-medium outline-none whitespace-nowrap',
     'transition-all duration-200 ease-in-out',
     'disabled:cursor-not-allowed disabled:opacity-50',
     'backdrop-blur-md',