refactor: change dark theme color

frontend/src/App.vue

@@ -11,7 +11,7 @@
  * emits a `capture:overlay` event with the screenshot payload so the
  * frontend knows when (and what) to render.
  */
-import { onMounted, onUnmounted, ref } from 'vue'
+import { computed, onMounted, onUnmounted, ref } from 'vue'
 import SettingsView from './views/SettingsView.vue'
 import Toast from './components/Toast.vue'
 import CaptureOverlay from './views/CaptureOverlay.vue'
@@ -24,6 +24,7 @@ import {
   SaveRegionToRemote,
   SummarizeRegion,
   CancelRegion,
+  GetConfig,
 } from '../wailsjs/go/main/App'
 
 type HotkeyStatus =
@@ -35,6 +36,25 @@ const hotkeyStatus = ref<HotkeyStatus>({ state: 'unknown' })
 type Mode = 'settings' | 'overlay'
 const mode = ref<Mode>('settings')
 
+type ThemeMode = 'auto' | 'light' | 'dark'
+const themeMode = ref<ThemeMode>('auto')
+const appThemeClass = computed(() => `theme-${themeMode.value}`)
+
+function normalizeTheme(theme: unknown): ThemeMode {
+  return theme === 'light' || theme === 'dark' || theme === 'auto'
+    ? theme
+    : 'auto'
+}
+
+async function loadThemePreference() {
+  try {
+    const cfg = await GetConfig()
+    themeMode.value = normalizeTheme((cfg as any)?.theme)
+  } catch {
+    themeMode.value = 'auto'
+  }
+}
+
 // `SettingsTab` is hoisted to the App shell so the sidebar (which lives
 // here) and the inner SettingsView (which renders the matching card) can
 // share a single source of truth without an event bus.
@@ -224,6 +244,7 @@ async function onOverlayCancel() {
 }
 
 onMounted(() => {
+  void loadThemePreference()
   EventsOn('capture:start', () => {
     capturing.value = true
   })
@@ -286,7 +307,7 @@ onUnmounted(() => {
   />
 
   <!-- Settings mode: standard desktop window; macOS title bar is native. -->
-  <div v-else class="app-root">
+  <div v-else class="app-root" :class="appThemeClass">
     <div v-if="hotkeyStatus.state === 'error'" class="permission-banner">
       <div>
         <strong>Global hotkey is not active.</strong>
@@ -312,7 +333,11 @@ onUnmounted(() => {
         </div>
       </aside>
       <section class="content">
-        <SettingsView :tab="activeTab" />
+        <SettingsView
+          :tab="activeTab"
+          :theme="themeMode"
+          @theme-change="themeMode = normalizeTheme($event)"
+        />
       </section>
     </main>
 
@@ -344,6 +369,15 @@ onUnmounted(() => {
   color: #111827;
   font-size: 13px;
 }
+.app-root.theme-light {
+  color-scheme: light;
+}
+.app-root.theme-dark {
+  color-scheme: dark;
+}
+.app-root.theme-auto {
+  color-scheme: light dark;
+}
 
 .status-pill {
   font-size: 11px;
@@ -498,33 +532,64 @@ onUnmounted(() => {
   }
 }
 
-@media (prefers-color-scheme: dark) {
+.app-root.theme-dark {
-  .app-root {
   background: #1c1d22;
   color: #e5e7eb;
 }
-  .titlebar {
+.app-root.theme-dark .titlebar {
   background: rgba(28, 29, 34, 0.7);
   border-bottom-color: #2c2f36;
 }
-  .titlebar-title {
+.app-root.theme-dark .titlebar-title {
   color: #f3f4f6;
 }
-  .sidebar {
+.app-root.theme-dark .sidebar {
   background: rgba(0, 0, 0, 0.15);
   border-right-color: #2c2f36;
 }
-  .sidebar-item {
+.app-root.theme-dark .sidebar-item {
   color: #d1d5db;
 }
-  .sidebar-item:hover:not(.active) {
+.app-root.theme-dark .sidebar-item:hover:not(.active) {
   background: rgba(255, 255, 255, 0.05);
 }
-  .sidebar-item.active {
+.app-root.theme-dark .sidebar-item.active {
   background: rgba(59, 130, 246, 0.18);
   color: #93c5fd;
 }
-  .permission-banner {
+.app-root.theme-dark .permission-banner {
+  background: rgba(120, 53, 15, 0.3);
+  border-color: rgba(253, 186, 116, 0.4);
+  color: #fed7aa;
+}
+
+@media (prefers-color-scheme: dark) {
+  .app-root.theme-auto {
+    background: #1c1d22;
+    color: #e5e7eb;
+  }
+  .app-root.theme-auto .titlebar {
+    background: rgba(28, 29, 34, 0.7);
+    border-bottom-color: #2c2f36;
+  }
+  .app-root.theme-auto .titlebar-title {
+    color: #f3f4f6;
+  }
+  .app-root.theme-auto .sidebar {
+    background: rgba(0, 0, 0, 0.15);
+    border-right-color: #2c2f36;
+  }
+  .app-root.theme-auto .sidebar-item {
+    color: #d1d5db;
+  }
+  .app-root.theme-auto .sidebar-item:hover:not(.active) {
+    background: rgba(255, 255, 255, 0.05);
+  }
+  .app-root.theme-auto .sidebar-item.active {
+    background: rgba(59, 130, 246, 0.18);
+    color: #93c5fd;
+  }
+  .app-root.theme-auto .permission-banner {
     background: rgba(120, 53, 15, 0.3);
     border-color: rgba(253, 186, 116, 0.4);
     color: #fed7aa;

frontend/src/views/SettingsView.vue

@@ -12,7 +12,7 @@
  *
  * State flow: load() pulls config from Go on mount, save() pushes back.
  */
-import { computed, onMounted, ref } from 'vue'
+import { computed, onMounted, ref, watch } from 'vue'
 import {
   GetConfig,
   SaveConfig,
@@ -24,9 +24,15 @@ import {
 // Tab discriminator shared with the App shell. Kept as a string union so
 // the parent can pass the value without importing a type from this view.
 type TabId = 'general' | 's3' | 'ssh' | 'llm'
+type ThemeMode = 'auto' | 'light' | 'dark'
 
 const props = defineProps<{
   tab: TabId
+  theme: ThemeMode
+}>()
+
+const emit = defineEmits<{
+  (event: 'theme-change', theme: ThemeMode): void
 }>()
 
 interface S3Config {
@@ -70,6 +76,7 @@ interface LLMConfig {
 
 interface AppConfig {
   hotkey: string
+  theme: ThemeMode
   s3: S3Config
   ssh: SSHConfig
   llm: LLMConfig
@@ -81,6 +88,12 @@ const llmProviderOptions = [
   { id: 'openai', label: 'ChatGPT / OpenAI-compatible' },
 ]
 
+const themeOptions: Array<{ id: ThemeMode; label: string }> = [
+  { id: 'light', label: '浅色' },
+  { id: 'dark', label: '深色' },
+  { id: 'auto', label: '自动' },
+]
+
 const DEFAULT_SUMMARY_PROMPT = `你是一个截图内容总结助手。请阅读截图，并用中文输出一段适合直接粘贴到聊天、工单、Issue 或 PR 中的说明。
 
 要求：
@@ -97,6 +110,7 @@ const DEFAULT_SUMMARY_PROMPT = `你是一个截图内容总结助手。请阅读
 function defaultConfig(): AppConfig {
   return {
     hotkey: 'cmd+shift+a',
+    theme: 'auto',
     s3: {
       endpoint: '',
       region: 'us-east-1',
@@ -184,6 +198,12 @@ const activeLLMProvider = computed(() => {
   return config.value.llm.providers[id]
 })
 
+function normalizeTheme(theme: unknown): ThemeMode {
+  return theme === 'light' || theme === 'dark' || theme === 'auto'
+    ? theme
+    : 'auto'
+}
+
 function flash(kind: 'ok' | 'err', text: string) {
   message.value = { kind, text }
   window.setTimeout(() => {
@@ -205,7 +225,9 @@ async function load() {
       ...defaultConfig().llm.providers,
       ...((cfg as any).llm?.providers ?? {}),
     }
+    merged.theme = normalizeTheme((cfg as any).theme)
     config.value = merged
+    emit('theme-change', config.value.theme)
   }
 }
 
@@ -249,11 +271,16 @@ async function manualCapture() {
   await CaptureNow()
 }
 
+watch(
+  () => config.value.theme,
+  (theme) => emit('theme-change', normalizeTheme(theme))
+)
+
 onMounted(load)
 </script>
 
 <template>
-  <div class="settings">
+  <div class="settings" :class="`theme-${props.theme}`">
     <header class="hero">
       <div>
         <h1>SnapGo</h1>
@@ -265,9 +292,10 @@ onMounted(load)
       <button class="btn primary" @click="manualCapture">Capture now</button>
     </header>
 
-    <!-- General tab — only the shortcut configuration lives here. -->
+    <!-- General tab — shortcut and appearance configuration. -->
     <section v-if="props.tab === 'general'" class="card">
-      <h2>Shortcut</h2>
+      <h2>General</h2>
+      <div class="grid">
         <label class="field">
           <span>Global hotkey</span>
           <input
@@ -276,6 +304,19 @@ onMounted(load)
             spellcheck="false"
           />
         </label>
+        <label class="field">
+          <span>主题选择</span>
+          <select v-model="config.theme">
+            <option
+              v-for="themeOption in themeOptions"
+              :key="themeOption.id"
+              :value="themeOption.id"
+            >
+              {{ themeOption.label }}
+            </option>
+          </select>
+        </label>
+      </div>
       <p class="hint">
         Tokens (case-insensitive, "+"-separated): cmd / ctrl / option / shift +
         a–z or 0–9. Example: <code>cmd+shift+a</code>.
@@ -564,6 +605,15 @@ onMounted(load)
   padding: 28px 32px 60px;
   color: #1f2937;
 }
+.settings.theme-light {
+  color-scheme: light;
+}
+.settings.theme-dark {
+  color-scheme: dark;
+}
+.settings.theme-auto {
+  color-scheme: light dark;
+}
 .hero {
   display: flex;
   align-items: center;
@@ -779,51 +829,100 @@ kbd {
 .fade-leave-to {
   opacity: 0;
 }
-@media (prefers-color-scheme: dark) {
+.settings.theme-dark {
-  .settings {
   color: #e5e7eb;
 }
-  .card {
+.settings.theme-dark .card {
   background: #1f2937;
   border-color: #374151;
 }
-  .field input,
+.settings.theme-dark .field span {
-  .field textarea {
+  color: #d1d5db;
+}
+.settings.theme-dark .field input[type='text'],
+.settings.theme-dark .field input[type='number'],
+.settings.theme-dark .field input:not([type='checkbox']),
+.settings.theme-dark .field select,
+.settings.theme-dark .field textarea {
   background: #111827;
   border-color: #374151;
   color: #fff;
 }
-  .field select {
+.settings.theme-dark .field input::placeholder,
-    background: #111827;
+.settings.theme-dark .field textarea::placeholder {
-    border-color: #374151;
-    color: #fff;
-  }
-  .field input::placeholder,
-  .field textarea::placeholder {
   color: #9ca3af;
 }
-  .field input:disabled {
+.settings.theme-dark .field input:disabled {
   background: #1f2937;
   color: #6b7280;
 }
-  .prefixed-input {
+.settings.theme-dark .prefixed-input {
   background: #111827;
   border-color: #374151;
 }
-  .input-prefix {
+.settings.theme-dark .input-prefix {
   background: #1f2937;
   border-right-color: #374151;
   color: #d1d5db;
 }
-  .btn {
+.settings.theme-dark .btn:not(.primary) {
   background: #1f2937;
   border-color: #374151;
   color: #e5e7eb;
 }
-  .btn:hover:not(:disabled) {
+.settings.theme-dark .btn:not(.primary):hover:not(:disabled) {
   background: #374151;
 }
-  .subtitle {
+.settings.theme-dark .subtitle {
+  color: #9ca3af;
+}
+
+@media (prefers-color-scheme: dark) {
+  .settings.theme-auto {
+    color: #e5e7eb;
+  }
+  .settings.theme-auto .card {
+    background: #1f2937;
+    border-color: #374151;
+  }
+  .settings.theme-auto .field span {
+    color: #d1d5db;
+  }
+  .settings.theme-auto .field input[type='text'],
+  .settings.theme-auto .field input[type='number'],
+  .settings.theme-auto .field input:not([type='checkbox']),
+  .settings.theme-auto .field select,
+  .settings.theme-auto .field textarea {
+    background: #111827;
+    border-color: #374151;
+    color: #fff;
+  }
+  .settings.theme-auto .field input::placeholder,
+  .settings.theme-auto .field textarea::placeholder {
+    color: #9ca3af;
+  }
+  .settings.theme-auto .field input:disabled {
+    background: #1f2937;
+    color: #6b7280;
+  }
+  .settings.theme-auto .prefixed-input {
+    background: #111827;
+    border-color: #374151;
+  }
+  .settings.theme-auto .input-prefix {
+    background: #1f2937;
+    border-right-color: #374151;
+    color: #d1d5db;
+  }
+  .settings.theme-auto .btn:not(.primary) {
+    background: #1f2937;
+    border-color: #374151;
+    color: #e5e7eb;
+  }
+  .settings.theme-auto .btn:not(.primary):hover:not(:disabled) {
+    background: #374151;
+  }
+  .settings.theme-auto .subtitle {
     color: #9ca3af;
   }
 }

frontend/wailsjs/go/models.ts

@@ -167,6 +167,7 @@ export namespace domain {
 	}
 	export class AppConfig {
 	    hotkey: string;
+	    theme: string;
 	    s3: S3Config;
 	    ssh: SSHConfig;
 	    llm: LLMConfig;
@@ -178,6 +179,7 @@ export namespace domain {
 	    constructor(source: any = {}) {
 	        if ('string' === typeof source) source = JSON.parse(source);
 	        this.hotkey = source["hotkey"];
+	        this.theme = source["theme"];
 	        this.s3 = this.convertValues(source["s3"], S3Config);
 	        this.ssh = this.convertValues(source["ssh"], SSHConfig);
 	        this.llm = this.convertValues(source["llm"], LLMConfig);

internal/domain/config.go

@@ -117,6 +117,13 @@ const (
 	LLMProviderOpenAI = "openai"
 )
 
+// Theme preference identifiers stored in AppConfig.Theme.
+const (
+	ThemeAuto  = "auto"
+	ThemeLight = "light"
+	ThemeDark  = "dark"
+)
+
 const DefaultSummaryPrompt = `你是一个截图内容总结助手。请阅读截图，并用中文输出一段适合直接粘贴到聊天、工单、Issue 或 PR 中的说明。
 
 要求：
@@ -141,6 +148,9 @@ type AppConfig struct {
 	// in the infrastructure hotkey adapter.
 	Hotkey string `json:"hotkey"`
 
+	// Theme controls the settings UI appearance: "auto", "light", or "dark".
+	Theme string `json:"theme"`
+
 	// S3 holds the active S3-compatible storage configuration.
 	S3 S3Config `json:"s3"`
 
@@ -156,6 +166,7 @@ type AppConfig struct {
 func DefaultAppConfig() AppConfig {
 	cfg := AppConfig{
 		Hotkey: "cmd+shift+a",
+		Theme:  ThemeAuto,
 		S3: S3Config{
 			PathPrefix:   "snapgo/",
 			UsePathStyle: true,
@@ -214,6 +225,9 @@ func (c *AppConfig) Normalize() {
 	if c.Hotkey == "" {
 		c.Hotkey = "cmd+shift+a"
 	}
+	if c.Theme != ThemeLight && c.Theme != ThemeDark && c.Theme != ThemeAuto {
+		c.Theme = ThemeAuto
+	}
 	if c.S3.PathPrefix == "" {
 		c.S3.PathPrefix = "snapgo/"
 	}