feat: add dark theme support with CSS custom properties and Naive UI integration

Implement runtime theme switching using CSS custom properties delegated through SCSS variables, with light/dark/system modes, FOUC prevention, sidebar toggle, and settings selector. Add theme-aware video assets for sidebar and chat thinking indicator.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/client/src/components/hermes/chat/ChatInput.vue

@@ -331,7 +331,7 @@ function isImage(type: string): boolean {
   border-radius: 50%;
   border: none;
   background: rgba(0, 0, 0, 0.5);
-  color: #fff;
+  color: var(--text-on-overlay);
   display: flex;
   align-items: center;
   justify-content: center;
@@ -394,8 +394,8 @@ function isImage(type: string): boolean {
 
 // Drag-over state
 .input-wrapper.drag-over {
-  border-color: #4a90d9;
+  border-color: var(--accent-info);
   border-style: dashed;
-  background-color: rgba(74, 144, 217, 0.04);
+  background-color: rgba(var(--accent-info-rgb), 0.04);
 }
 </style>

packages/client/src/components/hermes/chat/MarkdownRenderer.vue

@@ -105,7 +105,7 @@ const renderedHtml = computed(() => md.render(props.content))
     }
 
     th {
-      background: rgba($accent-primary, 0.08);
+      background: rgba(var(--accent-primary-rgb), 0.08);
       color: $text-primary;
       font-weight: 600;
     }
@@ -189,4 +189,20 @@ const renderedHtml = computed(() => md.render(props.content))
 .hljs-title\.function_ { color: #1a1a1a; }
 .hljs-params { color: #2a2a2a; }
 .hljs-meta { color: #999999; }
+
+// Dark mode highlight.js — inverted pure ink
+.dark .hljs { color: #d0d0d0; }
+.dark .hljs-keyword,
+.dark .hljs-selector-tag { color: #f0f0f0; font-weight: 600; }
+.dark .hljs-string,
+.dark .hljs-attr { color: #aaaaaa; }
+.dark .hljs-number { color: #cccccc; }
+.dark .hljs-comment { color: #666666; font-style: italic; }
+.dark .hljs-built_in { color: #bbbbbb; }
+.dark .hljs-type { color: #c6c6c6; }
+.dark .hljs-variable { color: #f0f0f0; }
+.dark .hljs-title,
+.dark .hljs-title\.function_ { color: #f0f0f0; }
+.dark .hljs-params { color: #d0d0d0; }
+.dark .hljs-meta { color: #666666; }
 </style>

packages/client/src/components/hermes/chat/MessageItem.vue

@@ -201,7 +201,7 @@ const formattedToolResult = computed(() => {
 
     .message-bubble {
       background-color: $msg-user-bg;
-      border-radius: $radius-md $radius-md 4px $radius-md;
+      border-radius: 10px;
     }
   }
 
@@ -223,7 +223,7 @@ const formattedToolResult = computed(() => {
 
     .message-bubble {
       background-color: $msg-assistant-bg;
-      border-radius: $radius-md $radius-md $radius-md 4px;
+      border-radius: 10px;
     }
   }
 
@@ -238,7 +238,7 @@ const formattedToolResult = computed(() => {
       border-left: 3px solid $warning;
       border-radius: $radius-sm;
       max-width: 80%;
-      background-color: rgba($warning, 0.06);
+      background-color: rgba(var(--warning-rgb), 0.06);
     }
   }
 }
@@ -261,6 +261,7 @@ const formattedToolResult = computed(() => {
   font-size: 14px;
   line-height: 1.65;
   word-break: break-word;
+  border-radius: 10px;
 }
 
 .msg-attachments {
@@ -315,6 +316,10 @@ const formattedToolResult = computed(() => {
   color: $text-muted;
   margin-top: 4px;
   padding: 0 4px;
+
+  .dark & {
+    color: #999999;
+  }
 }
 
 .tool-line {
@@ -369,7 +374,7 @@ const formattedToolResult = computed(() => {
 .tool-error-badge {
   font-size: 9px;
   color: $error;
-  background: rgba($error, 0.08);
+  background: rgba(var(--error-rgb), 0.08);
   padding: 0 4px;
   border-radius: 3px;
   line-height: 14px;

packages/client/src/components/hermes/chat/MessageList.vue

@@ -91,7 +91,11 @@ watch(currentToolCalls, scrollToBottom)
   display: flex;
   flex-direction: column;
   gap: 16px;
-  background-color: #ffffff;
+  background-color: $bg-card;
+
+  .dark & {
+    background-color: #333333;
+  }
 }
 
 .empty-state {

packages/client/src/components/hermes/jobs/JobCard.vue

@@ -152,7 +152,7 @@ async function handleDelete() {
   transition: border-color $transition-fast;
 
   &:hover {
-    border-color: rgba($accent-primary, 0.3);
+    border-color: rgba(var(--accent-primary-rgb), 0.3);
   }
 }
 
@@ -180,22 +180,22 @@ async function handleDelete() {
   font-weight: 500;
 
   &.success {
-    background: rgba($success, 0.12);
+    background: rgba(var(--success-rgb), 0.12);
     color: $success;
   }
 
   &.info {
-    background: rgba($accent-primary, 0.12);
+    background: rgba(var(--accent-primary-rgb), 0.12);
     color: $accent-primary;
   }
 
   &.warning {
-    background: rgba($warning, 0.12);
+    background: rgba(var(--warning-rgb), 0.12);
     color: $warning;
   }
 
   &.error {
-    background: rgba($error, 0.12);
+    background: rgba(var(--error-rgb), 0.12);
     color: $error;
   }
 }

packages/client/src/components/hermes/models/ProviderCard.vue

@@ -70,7 +70,7 @@ async function handleDelete() {
   transition: border-color $transition-fast;
 
   &:hover {
-    border-color: rgba($accent-primary, 0.3);
+    border-color: rgba(var(--accent-primary-rgb), 0.3);
   }
 }
 
@@ -98,12 +98,12 @@ async function handleDelete() {
   font-weight: 500;
 
   &.builtin {
-    background: rgba($accent-primary, 0.12);
+    background: rgba(var(--accent-primary-rgb), 0.12);
     color: $accent-primary;
   }
 
   &.custom {
-    background: rgba($success, 0.12);
+    background: rgba(var(--success-rgb), 0.12);
     color: $success;
   }
 }

packages/client/src/components/hermes/profiles/ProfileCard.vue

@@ -181,11 +181,11 @@ async function handleExport() {
   transition: border-color $transition-fast;
 
   &:hover {
-    border-color: rgba($accent-primary, 0.3);
+    border-color: rgba(var(--accent-primary-rgb), 0.3);
   }
 
   &.active {
-    border-color: rgba($success, 0.4);
+    border-color: rgba(var(--success-rgb), 0.4);
   }
 }
 

packages/client/src/components/hermes/settings/DisplaySettings.vue

@@ -1,12 +1,20 @@
 <script setup lang="ts">
-import { NSwitch, useMessage } from 'naive-ui'
+import { NSwitch, NSelect, useMessage } from 'naive-ui'
 import { useI18n } from 'vue-i18n'
 import { useSettingsStore } from '@/stores/hermes/settings'
+import { useTheme, type ThemeMode } from '@/composables/useTheme'
 import SettingRow from './SettingRow.vue'
 
 const settingsStore = useSettingsStore()
 const message = useMessage()
 const { t } = useI18n()
+const { mode, setMode } = useTheme()
+
+const themeOptions = [
+  { label: t('settings.display.themeLight'), value: 'light' },
+  { label: t('settings.display.themeDark'), value: 'dark' },
+  { label: t('settings.display.themeSystem'), value: 'system' },
+]
 
 async function save(values: Record<string, any>) {
   try {
@@ -16,10 +24,19 @@ async function save(values: Record<string, any>) {
     message.error(t('settings.saveFailed'))
   }
 }
+
+function handleThemeChange(val: string) {
+  const m = val as ThemeMode
+  setMode(m)
+  save({ skin: m })
+}
 </script>
 
 <template>
   <section class="settings-section">
+    <SettingRow :label="t('settings.display.theme')" :hint="t('settings.display.themeHint')">
+      <NSelect :value="mode" :options="themeOptions" size="small" :consistent-menu-width="false" class="input-sm" @update:value="handleThemeChange" />
+    </SettingRow>
     <SettingRow :label="t('settings.display.streaming')" :hint="t('settings.display.streamingHint')">
       <NSwitch :value="settingsStore.display.streaming" @update:value="v => save({ streaming: v })" />
     </SettingRow>

packages/client/src/components/hermes/settings/PlatformCard.vue

@@ -57,7 +57,7 @@ const configured = computed(() => {
   overflow: hidden;
 
   &.configured {
-    border-color: rgba($success, 0.2);
+    border-color: rgba(var(--success-rgb), 0.2);
   }
 }
 
@@ -70,7 +70,7 @@ const configured = computed(() => {
   user-select: none;
 
   &:hover {
-    background-color: rgba($text-primary, 0.03);
+    background-color: rgba(var(--text-primary-rgb), 0.03);
   }
 }
 

packages/client/src/components/hermes/skills/SkillDetail.vue

@@ -185,7 +185,7 @@ watch(() => `${props.category}/${props.skill}`, loadSkill, { immediate: true })
   border-radius: 4px;
 
   &:hover {
-    background: rgba($accent-primary, 0.06);
+    background: rgba(var(--accent-primary-rgb), 0.06);
   }
 }
 

packages/client/src/components/hermes/skills/SkillList.vue

@@ -150,7 +150,7 @@ async function handleToggle(category: string, skillName: string, newEnabled: boo
   border-radius: $radius-sm;
 
   &:hover {
-    background: rgba($accent-primary, 0.04);
+    background: rgba(var(--accent-primary-rgb), 0.04);
   }
 }
 
@@ -174,7 +174,7 @@ async function handleToggle(category: string, skillName: string, newEnabled: boo
 .category-count {
   font-size: 11px;
   color: $text-muted;
-  background: rgba($accent-primary, 0.06);
+  background: rgba(var(--accent-primary-rgb), 0.06);
   padding: 1px 6px;
   border-radius: 8px;
 }
@@ -200,12 +200,12 @@ async function handleToggle(category: string, skillName: string, newEnabled: boo
   gap: 8px;
 
   &:hover {
-    background: rgba($accent-primary, 0.06);
+    background: rgba(var(--accent-primary-rgb), 0.06);
     color: $text-primary;
   }
 
   &.active {
-    background: rgba($accent-primary, 0.1);
+    background: rgba(var(--accent-primary-rgb), 0.1);
     color: $text-primary;
     font-weight: 500;
   }

packages/client/src/components/hermes/usage/DailyTrend.vue

@@ -127,6 +127,10 @@ import { computed } from 'vue'
   border-radius: 2px 2px 0 0;
   min-height: 0;
   transition: height 0.3s ease;
+
+  .dark & {
+    background: #66bb6a;
+  }
 }
 
 .bar-col {
@@ -140,7 +144,7 @@ import { computed } from 'vue'
   left: 50%;
   transform: translateX(-50%);
   background: $text-primary;
-  color: #fff;
+  color: var(--text-on-accent);
   padding: 6px 10px;
   border-radius: $radius-sm;
   font-size: 11px;

packages/client/src/components/hermes/usage/ModelBreakdown.vue

@@ -85,6 +85,10 @@ function formatTokens(n: number): string {
   border-radius: 3px;
   min-width: 2px;
   transition: width 0.3s ease;
+
+  .dark & {
+    background: #66bb6a;
+  }
 }
 
 .model-tokens {