diff --git a/docs/.vitepress/config.ts b/docs/.vitepress/config.ts
index 9a3d9224..cfc0d3ed 100644
--- a/docs/.vitepress/config.ts
+++ b/docs/.vitepress/config.ts
@@ -57,6 +57,7 @@ function sidebarGuide() {
   return [
     {
       text: 'Introduction',
+      collapsible: true,
       items: [
         { text: 'What is VitePress?', link: '/guide/what-is-vitepress' },
         { text: 'Getting Started', link: '/guide/getting-started' },
@@ -71,6 +72,7 @@ function sidebarGuide() {
     },
     {
       text: 'Theme',
+      collapsible: true,
       items: [
         { text: 'Introduction', link: '/guide/theme-introduction' },
         { text: 'Layout', link: '/guide/theme-layout' },
@@ -81,6 +83,7 @@ function sidebarGuide() {
     },
     {
       text: 'Migrations',
+      collapsible: true,
       items: [
         {
           text: 'Migration from VuePress',
diff --git a/src/client/theme-default/components/VPSidebar.vue b/src/client/theme-default/components/VPSidebar.vue
index a59b99be..c7511357 100644
--- a/src/client/theme-default/components/VPSidebar.vue
+++ b/src/client/theme-default/components/VPSidebar.vue
@@ -34,7 +34,12 @@ watchPostEffect(async () => {
       </span>
 
       <div v-for="group in sidebar" :key="group.text" class="group">
-        <VPSidebarGroup :text="group.text" :items="group.items" />
+        <VPSidebarGroup
+          :text="group.text"
+          :items="group.items"
+          :collapsible="group.collapsible"
+          :collapsed="group.collapsed"
+        />
       </div>
     </nav>
   </aside>
diff --git a/src/client/theme-default/components/VPSidebarGroup.vue b/src/client/theme-default/components/VPSidebarGroup.vue
index db9362ac..c5e52aad 100644
--- a/src/client/theme-default/components/VPSidebarGroup.vue
+++ b/src/client/theme-default/components/VPSidebarGroup.vue
@@ -1,38 +1,109 @@
 <script lang="ts" setup>
-import { useData } from 'vitepress'
+import { ref, onMounted } from 'vue'
 import { DefaultTheme } from '../config'
+import VPIconPlusSquare from './icons/VPIconPlusSquare.vue'
+import VPIconMinusSquare from './icons/VPIconMinusSquare.vue'
 import VPSidebarLink from './VPSidebarLink.vue'
 
 const props = defineProps<{
   text: string
   items: DefaultTheme.SidebarItem[]
+  collapsible?: boolean
+  collapsed?: boolean
 }>()
 
-const { page } = useData()
+const collapsed = ref(!!props.collapsed)
+
+function toggle() {
+  collapsed.value = !collapsed.value
+}
 </script>
 
 <template>
-  <section class="VPSidebarGroup">
-    <div class="title">
+  <section class="VPSidebarGroup" :class="{ collapsible, collapsed }">
+    <div class="title" role="button" @click="toggle">
       <h2 class="title-text">{{ text }}</h2>
+      <div class="action">
+        <VPIconMinusSquare class="icon minus" />
+        <VPIconPlusSquare class="icon plus" />
+      </div>
     </div>
 
-    <template v-for="item in items" :key="item.link">
-      <VPSidebarLink :item="item" />
-    </template>
+    <div class="items">
+      <template v-for="item in items" :key="item.link">
+        <VPSidebarLink :item="item" />
+      </template>
+    </div>
   </section>
 </template>
 
 <style scoped>
 .title {
-  padding: 6px 0;
+  display: flex;
+  justify-content: space-between;
+  align-items: flex-start;
+  z-index: 2;
+}
+
+.VPSidebarGroup.collapsible .title {
+  cursor: pointer;
 }
 
 .title-text {
+  padding-top: 6px;
+  padding-bottom: 6px;
   line-height: 20px;
   font-size: 14px;
   font-weight: 700;
   color: var(--vp-c-text-1);
-  transition: color 0.5s;
+}
+
+.action {
+  display: none;
+  position: relative;
+  margin-right: -8px;
+  border-radius: 4px;
+  width: 32px;
+  height: 32px;
+  color: var(--vp-c-text-3);
+  transition: color 0.25s;
+}
+
+.VPSidebarGroup.collapsible .action {
+  display: block;
+}
+
+.title:hover .action {
+  color: var(--vp-c-text-2);
+}
+
+.icon {
+  position: absolute;
+  top: 8px;
+  left: 8px;
+  width: 16px;
+  height: 16px;
+  fill: currentColor;
+}
+
+.icon.minus { opacity: 1; }
+.icon.plus  { opacity: 0; }
+
+.VPSidebarGroup.collapsed .icon.minus { opacity: 0; }
+.VPSidebarGroup.collapsed .icon.plus  { opacity: 1; }
+
+.items {
+  overflow: hidden;
+}
+
+.VPSidebarGroup.collapsed .items {
+  margin-bottom: -22px;
+  max-height: 0;
+}
+
+@media (min-width: 960px) {
+  .VPSidebarGroup.collapsed .items {
+    margin-bottom: -14px;
+  }
 }
 </style>
diff --git a/src/client/theme-default/components/icons/VPIconMinus.vue b/src/client/theme-default/components/icons/VPIconMinus.vue
new file mode 100644
index 00000000..e0229195
--- /dev/null
+++ b/src/client/theme-default/components/icons/VPIconMinus.vue
@@ -0,0 +1,5 @@
+<template>
+  <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24">
+    <path d="M22,13H2a1,1,0,0,1,0-2H22a1,1,0,0,1,0,2Z" />
+  </svg>
+</template>
diff --git a/src/client/theme-default/components/icons/VPIconMinusSquare.vue b/src/client/theme-default/components/icons/VPIconMinusSquare.vue
new file mode 100644
index 00000000..266ae3da
--- /dev/null
+++ b/src/client/theme-default/components/icons/VPIconMinusSquare.vue
@@ -0,0 +1,6 @@
+<template>
+  <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 24 24">
+    <path d="M19,2H5C3.3,2,2,3.3,2,5v14c0,1.7,1.3,3,3,3h14c1.7,0,3-1.3,3-3V5C22,3.3,20.7,2,19,2zM20,19c0,0.6-0.4,1-1,1H5c-0.6,0-1-0.4-1-1V5c0-0.6,0.4-1,1-1h14c0.6,0,1,0.4,1,1V19z" />
+    <path d="M16,11H8c-0.6,0-1,0.4-1,1s0.4,1,1,1h8c0.6,0,1-0.4,1-1S16.6,11,16,11z" />
+  </svg>
+</template>
diff --git a/src/client/theme-default/components/icons/VPIconPlusSquare.vue b/src/client/theme-default/components/icons/VPIconPlusSquare.vue
new file mode 100644
index 00000000..88e5b5cf
--- /dev/null
+++ b/src/client/theme-default/components/icons/VPIconPlusSquare.vue
@@ -0,0 +1,6 @@
+<template>
+  <svg version="1.1" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24">
+    <path d="M19,2H5C3.3,2,2,3.3,2,5v14c0,1.7,1.3,3,3,3h14c1.7,0,3-1.3,3-3V5C22,3.3,20.7,2,19,2z M20,19c0,0.6-0.4,1-1,1H5c-0.6,0-1-0.4-1-1V5c0-0.6,0.4-1,1-1h14c0.6,0,1,0.4,1,1V19z" />
+    <path d="M16,11h-3V8c0-0.6-0.4-1-1-1s-1,0.4-1,1v3H8c-0.6,0-1,0.4-1,1s0.4,1,1,1h3v3c0,0.6,0.4,1,1,1s1-0.4,1-1v-3h3c0.6,0,1-0.4,1-1S16.6,11,16,11z" />
+  </svg>
+</template>
diff --git a/src/client/theme-default/styles/base.css b/src/client/theme-default/styles/base.css
index 3b270430..0a316094 100644
--- a/src/client/theme-default/styles/base.css
+++ b/src/client/theme-default/styles/base.css
@@ -10,6 +10,10 @@ html {
   -webkit-text-size-adjust: 100%;
 }
 
+html.dark {
+  color-scheme: dark;
+}
+
 body {
   margin: 0;
   width: 100%;
diff --git a/types/default-theme.d.ts b/types/default-theme.d.ts
index c61b1721..1166d2ac 100644
--- a/types/default-theme.d.ts
+++ b/types/default-theme.d.ts
@@ -82,6 +82,20 @@ export namespace DefaultTheme {
   export interface SidebarGroup {
     text: string
     items: SidebarItem[]
+
+    /**
+     * If `true`, toggle button is shown.
+     *
+     * @default false
+     */
+    collapsible?: boolean
+
+    /**
+     * If `true`, collapsible group is collapsed by default.
+     *
+     * @default false
+     */
+    collapsed?: boolean
   }
 
   export interface SidebarItem {