diff --git a/src/components/AppLayout.vue b/src/components/AppLayout.vue
index 9631314..6112756 100644
--- a/src/components/AppLayout.vue
+++ b/src/components/AppLayout.vue
@@ -8,9 +8,26 @@ import DashboardView from './dashboard/DashboardView.vue'
 const { init } = useMqttBridge()
 
 const activeTab = ref<'connections' | 'presets' | 'dashboard'>('dashboard')
+const isDark = ref(false)
+
+function toggleTheme() {
+  isDark.value = !isDark.value
+  document.documentElement.classList.toggle('dark', isDark.value)
+  try {
+    localStorage.setItem('mqttx_theme', isDark.value ? 'dark' : 'light')
+  } catch { /* ignore */ }
+}
 
 onMounted(() => {
   init()
+  // Restore theme preference
+  try {
+    const saved = localStorage.getItem('mqttx_theme')
+    if (saved === 'dark') {
+      isDark.value = true
+      document.documentElement.classList.add('dark')
+    }
+  } catch { /* ignore */ }
 })
 </script>
 
@@ -50,7 +67,12 @@ onMounted(() => {
           预设
         </button>
       </div>
-      <div class="header-right" />
+      <div class="header-right">
+        <button class="theme-btn" @click="toggleTheme" :title="isDark ? '切换亮色模式' : '切换暗色模式'">
+          <svg v-if="isDark" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><circle cx="12" cy="12" r="5"/><line x1="12" y1="1" x2="12" y2="3"/><line x1="12" y1="21" x2="12" y2="23"/><line x1="4.22" y1="4.22" x2="5.64" y2="5.64"/><line x1="18.36" y1="18.36" x2="19.78" y2="19.78"/><line x1="1" y1="12" x2="3" y2="12"/><line x1="21" y1="12" x2="23" y2="12"/><line x1="4.22" y1="19.78" x2="5.64" y2="18.36"/><line x1="18.36" y1="5.64" x2="19.78" y2="4.22"/></svg>
+          <svg v-else width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"/></svg>
+        </button>
+      </div>
     </header>
     <main class="app-main">
       <ConnectionList v-if="activeTab === 'connections'" />
@@ -65,7 +87,7 @@ onMounted(() => {
   display: flex;
   flex-direction: column;
   height: 100vh;
-  background: var(--el-bg-color-page);
+  background: var(--comfort-bg);
 }
 
 /* ─── Header ─────────────────────────────────────────────────── */
@@ -74,8 +96,8 @@ onMounted(() => {
   align-items: center;
   padding: 0 16px;
   height: 48px;
-  background: var(--el-bg-color);
-  border-bottom: 1px solid var(--el-border-color-light);
+  background: var(--comfort-bg-card);
+  border-bottom: 1px solid var(--comfort-border);
   flex-shrink: 0;
   gap: 24px;
 }
@@ -94,13 +116,13 @@ onMounted(() => {
 .brand-name {
   font-size: 18px;
   font-weight: 700;
-  color: var(--el-color-primary);
+  color: var(--comfort-primary);
   letter-spacing: 0.5px;
 }
 .brand-version {
   font-size: 11px;
-  color: var(--el-text-color-placeholder);
-  background: var(--el-fill-color);
+  color: var(--comfort-text-muted);
+  background: var(--comfort-fill-color, var(--el-fill-color));
   padding: 0 5px;
   border-radius: 4px;
   line-height: 18px;
@@ -110,7 +132,7 @@ onMounted(() => {
 .header-tabs {
   display: flex;
   gap: 2px;
-  background: var(--el-fill-color);
+  background: var(--comfort-fill-color, var(--el-fill-color));
   padding: 2px;
   border-radius: 8px;
 }
@@ -124,26 +146,49 @@ onMounted(() => {
   background: transparent;
   border-radius: 6px;
   font-size: 13px;
-  color: var(--el-text-color-secondary);
+  color: var(--comfort-text-secondary);
   cursor: pointer;
   transition: all 0.15s;
   font-family: inherit;
   white-space: nowrap;
 }
 .tab-btn:hover {
-  color: var(--el-text-color-primary);
+  color: var(--comfort-text);
 }
 .tab-btn.active {
-  background: var(--el-bg-color);
-  color: var(--el-color-primary);
+  background: var(--comfort-bg-card);
+  color: var(--comfort-primary);
   font-weight: 500;
-  box-shadow: 0 1px 2px rgba(0,0,0,0.06);
+  box-shadow: var(--comfort-shadow);
 }
 .tab-btn svg {
   flex-shrink: 0;
 }
 .header-right {
   flex: 1;
+  display: flex;
+  justify-content: flex-end;
+}
+.theme-btn {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 30px;
+  height: 30px;
+  border: 1px solid var(--comfort-border);
+  border-radius: 6px;
+  background: var(--comfort-bg-card);
+  color: var(--comfort-text-secondary);
+  cursor: pointer;
+  transition: all 0.2s;
+}
+.theme-btn:hover {
+  color: var(--comfort-primary);
+  border-color: var(--comfort-primary-light);
+  background: var(--comfort-primary-bg);
+}
+.theme-btn svg {
+  flex-shrink: 0;
 }
 
 /* ─── Main ───────────────────────────────────────────────────── */
diff --git a/src/main.ts b/src/main.ts
index ce20f7c..9460517 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,6 +1,7 @@
 import { createApp } from "vue";
 import ElementPlus from "element-plus";
 import "element-plus/dist/index.css";
+import "./styles/comfort.css";
 import App from "./App.vue";
 
 const app = createApp(App);
diff --git a/src/styles/comfort.css b/src/styles/comfort.css
new file mode 100644
index 0000000..3ce3d17
--- /dev/null
+++ b/src/styles/comfort.css
@@ -0,0 +1,229 @@
+:root {
+  /* ─── Soft color palette ─────────────────────────────────────── */
+  --comfort-bg: #f5f5f0;
+  --comfort-bg-soft: #fafaf7;
+  --comfort-bg-card: #ffffff;
+  --comfort-text: #2c2c2c;
+  --comfort-text-secondary: #6b6b6b;
+  --comfort-text-muted: #999999;
+  --comfort-border: #e8e8e3;
+  --comfort-border-light: #f0f0eb;
+  --comfort-shadow: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.03);
+  --comfort-shadow-hover: 0 2px 8px rgba(0, 0, 0, 0.06), 0 1px 3px rgba(0, 0, 0, 0.04);
+  --comfort-primary: #5b8c5a;
+  --comfort-primary-light: #7dab7c;
+  --comfort-primary-bg: #eef5ee;
+  --comfort-success: #5b8c5a;
+  --comfort-warning: #c4a35a;
+  --comfort-danger: #c46a5a;
+  --comfort-info: #6b8a9a;
+  --comfort-font: "Inter", "LXGW WenKai", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
+  --comfort-font-mono: "Cascadia Code", "JetBrains Mono", "Fira Code", "Consolas", monospace;
+  --comfort-radius: 8px;
+  --comfort-radius-sm: 6px;
+
+  /* Element Plus variable overrides */
+  --el-bg-color: var(--comfort-bg);
+  --el-bg-color-overlay: var(--comfort-bg-card);
+  --el-text-color-primary: var(--comfort-text);
+  --el-text-color-regular: var(--comfort-text);
+  --el-text-color-secondary: var(--comfort-text-secondary);
+  --el-text-color-placeholder: var(--comfort-text-muted);
+  --el-border-color: var(--comfort-border);
+  --el-border-color-light: var(--comfort-border-light);
+  --el-border-color-extra-light: var(--comfort-border-light);
+  --el-fill-color: #efefea;
+  --el-fill-color-light: #eaeae5;
+  --el-fill-color-lighter: #f0f0eb;
+  --el-fill-color-extra-light: #f5f5f0;
+  --el-color-primary: var(--comfort-primary);
+  --el-color-primary-light-3: var(--comfort-primary-light);
+  --el-color-primary-light-5: #9dc09c;
+  --el-color-primary-light-7: #bdd5bc;
+  --el-color-primary-light-8: #d0e2cf;
+  --el-color-primary-light-9: var(--comfort-primary-bg);
+  --el-color-primary-dark-2: #4a7a49;
+  --el-color-success: var(--comfort-success);
+  --el-color-warning: var(--comfort-warning);
+  --el-color-danger: var(--comfort-danger);
+  --el-color-info: var(--comfort-info);
+  --el-border-radius-base: var(--comfort-radius-sm);
+  --el-font-size-base: 13px;
+  --el-font-size-small: 12px;
+  --el-font-size-extra-small: 11px;
+  --el-font-family: var(--comfort-font);
+}
+
+/* ─── Dark mode ─────────────────────────────────────────────────── */
+.dark {
+  --comfort-bg: #1a1a1e;
+  --comfort-bg-soft: #222226;
+  --comfort-bg-card: #2a2a2e;
+  --comfort-text: #e0e0e0;
+  --comfort-text-secondary: #a0a0a0;
+  --comfort-text-muted: #707070;
+  --comfort-border: #3a3a3e;
+  --comfort-border-light: #323236;
+  --comfort-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
+  --comfort-shadow-hover: 0 2px 8px rgba(0, 0, 0, 0.3);
+  --comfort-primary: #7dab7c;
+  --comfort-primary-light: #9dc09c;
+  --comfort-primary-bg: #2a3a2a;
+  --comfort-success: #7dab7c;
+  --comfort-warning: #c4a35a;
+  --comfort-danger: #c46a5a;
+  --comfort-info: #6b8a9a;
+
+  --el-bg-color: var(--comfort-bg);
+  --el-bg-color-overlay: var(--comfort-bg-card);
+  --el-text-color-primary: var(--comfort-text);
+  --el-text-color-regular: var(--comfort-text);
+  --el-text-color-secondary: var(--comfort-text-secondary);
+  --el-text-color-placeholder: var(--comfort-text-muted);
+  --el-border-color: var(--comfort-border);
+  --el-border-color-light: var(--comfort-border-light);
+  --el-fill-color: #2e2e32;
+  --el-fill-color-light: #36363a;
+  --el-fill-color-lighter: #323236;
+  --el-fill-color-extra-light: #2a2a2e;
+  --el-color-primary: var(--comfort-primary);
+  --el-color-primary-light-3: var(--comfort-primary-light);
+  --el-color-primary-light-5: #bdd5bc;
+  --el-color-primary-light-7: #3a4a3a;
+  --el-color-primary-light-8: #324032;
+  --el-color-primary-light-9: var(--comfort-primary-bg);
+  --el-color-primary-dark-2: #5b8c5a;
+}
+
+/* ─── Global comfort styles ─────────────────────────────────────── */
+body {
+  background: var(--comfort-bg);
+  color: var(--comfort-text);
+  font-family: var(--comfort-font);
+  line-height: 1.6;
+  -webkit-font-smoothing: antialiased;
+  text-rendering: optimizeLegibility;
+}
+
+/* Softer scrollbar */
+::-webkit-scrollbar {
+  width: 6px;
+  height: 6px;
+}
+::-webkit-scrollbar-track {
+  background: transparent;
+}
+::-webkit-scrollbar-thumb {
+  background: var(--comfort-border);
+  border-radius: 3px;
+}
+::-webkit-scrollbar-thumb:hover {
+  background: var(--comfort-text-muted);
+}
+
+/* Subtle transitions */
+* {
+  transition: background-color 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
+}
+
+/* Card style */
+.comfort-card {
+  background: var(--comfort-bg-card);
+  border: 1px solid var(--comfort-border);
+  border-radius: var(--comfort-radius);
+  box-shadow: var(--comfort-shadow);
+}
+
+/* Better focus ring */
+:focus-visible {
+  outline: 2px solid var(--comfort-primary-light);
+  outline-offset: 2px;
+  border-radius: 2px;
+}
+
+/* Input/textarea comfort */
+.el-input__wrapper,
+.el-textarea__inner {
+  box-shadow: none !important;
+  border: 1px solid var(--comfort-border) !important;
+  background: var(--comfort-bg-soft) !important;
+  border-radius: var(--comfort-radius-sm) !important;
+}
+.el-input__wrapper:hover,
+.el-textarea__inner:hover {
+  border-color: var(--comfort-primary-light) !important;
+}
+.el-input__wrapper.is-focus,
+.el-textarea__inner:focus {
+  border-color: var(--comfort-primary) !important;
+}
+
+/* Button comfort */
+.el-button {
+  --el-button-hover-bg-color: var(--comfort-primary-bg);
+  --el-button-hover-border-color: var(--comfort-primary-light);
+  border-radius: var(--comfort-radius-sm) !important;
+  font-weight: 450 !important;
+}
+.el-button--primary {
+  --el-button-bg-color: var(--comfort-primary);
+  --el-button-border-color: var(--comfort-primary);
+  --el-button-hover-bg-color: var(--comfort-primary-light);
+  --el-button-hover-border-color: var(--comfort-primary-light);
+}
+
+/* Table comfort */
+.el-table {
+  --el-table-border-color: var(--comfort-border-light) !important;
+  --el-table-header-bg-color: var(--comfort-bg-soft) !important;
+  --el-table-row-hover-bg-color: var(--comfort-primary-bg) !important;
+  font-size: 13px !important;
+}
+.el-table th.el-table__cell {
+  font-weight: 600 !important;
+  color: var(--comfort-text-secondary) !important;
+  font-size: 12px !important;
+  text-transform: uppercase;
+  letter-spacing: 0.3px;
+}
+
+/* Dialog comfort */
+.el-dialog {
+  --el-dialog-bg-color: var(--comfort-bg-card);
+  border-radius: var(--comfort-radius) !important;
+  box-shadow: var(--comfort-shadow-hover) !important;
+}
+
+/* Tag comfort */
+.el-tag {
+  --el-tag-bg-color: var(--comfort-primary-bg);
+  --el-tag-border-color: transparent;
+  --el-tag-text-color: var(--comfort-primary);
+  font-weight: 450;
+  border-radius: 4px;
+}
+
+/* Select dropdown comfort */
+.el-select-dropdown {
+  --el-select-dropdown-bg: var(--comfort-bg-card);
+  border: 1px solid var(--comfort-border) !important;
+  box-shadow: var(--comfort-shadow-hover) !important;
+  border-radius: var(--comfort-radius-sm) !important;
+}
+.el-select-dropdown__item.hover {
+  background: var(--comfort-primary-bg) !important;
+}
+
+/* Message comfort */
+.el-message {
+  border-radius: var(--comfort-radius-sm) !important;
+  box-shadow: var(--comfort-shadow-hover) !important;
+  border: 1px solid var(--comfort-border) !important;
+}
+
+/* Checkbox comfort */
+.el-checkbox {
+  --el-checkbox-checked-bg-color: var(--comfort-primary);
+  --el-checkbox-checked-input-border-color: var(--comfort-primary);
+  --el-checkbox-input-border-color-hover: var(--comfort-primary-light);
+}
\ No newline at end of file