diff --git a/frontend/src/App.vue b/frontend/src/App.vue
index 83f6362..66b9a62 100644
--- a/frontend/src/App.vue
+++ b/frontend/src/App.vue
@@ -35,6 +35,7 @@ const error = ref('')
 const notice = ref('')
 const loading = ref(false)
 const mobileSidebar = ref(false)
+const sidebarCollapsed = ref(false)
 const mobileDetail = ref(false)
 const mobileMore = ref(false)
 const moreSettingsOpen = ref(false)
@@ -50,6 +51,15 @@ const taskSwipeStart = ref<{ id: string; x: number; y: number } | null>(null)
 const taskSwipeOffsets = ref<Record<string, number>>({})
 let suppressTaskClickId = ''
 
+function toggleSidebar() {
+  const compact = window.matchMedia('(max-width: 930px)').matches
+  if (compact) {
+    mobileSidebar.value = !mobileSidebar.value
+  } else {
+    sidebarCollapsed.value = !sidebarCollapsed.value
+  }
+}
+
 const modalVisible = ref(false)
 const modalTitle = ref('')
 const modalLabel = ref('')
@@ -401,7 +411,7 @@ onMounted(bootstrap)
       <small v-if="error" role="alert">{{ error }}</small>
     </section>
   </div>
-  <div v-else class="shell">
+  <div v-else class="shell" :class="{ 'sidebar-collapsed': sidebarCollapsed }">
     <div v-if="mobileSidebar || mobileDetail" class="scrim" @click="mobileSidebar=false;mobileDetail=false" />
     <aside class="sidebar" :class="{ open: mobileSidebar }">
       <div class="brand-row"><div class="brand small">do<span>do</span></div><button class="icon mobile-only" aria-label="关闭菜单" @click="mobileSidebar=false"><X /></button></div>
@@ -430,7 +440,7 @@ onMounted(bootstrap)
 
     <main>
       <header class="topbar">
-        <button class="icon mobile-only" aria-label="打开菜单" @click="mobileSidebar=true"><Menu /></button>
+        <button class="icon" :aria-label="(sidebarCollapsed ? '展开' : '收起') + '菜单'" :aria-expanded="sidebarCollapsed ? 'false' : 'true'" @click="toggleSidebar"><Menu /></button>
         <div><h1>{{ activeName }}</h1></div>
         <label v-if="['tasks','today','upcoming','trash'].includes(activeView)" class="search"><Search/><input v-model="query" placeholder="搜索任务…" aria-label="搜索任务"><kbd>⌘ K</kbd></label>
       </header>
diff --git a/frontend/src/style.css b/frontend/src/style.css
index 2891b24..e9a1671 100644
--- a/frontend/src/style.css
+++ b/frontend/src/style.css
@@ -3,7 +3,7 @@
 :root{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Noto Sans CJK SC",sans-serif;color:#2d2924;background:#f8f3e8;--accent:#f15a29;--accent-soft:#fbe6dc;--paper:#fffdf8;--sidebar:#f6f0e4;--line:#e7ddcc;--muted:#8b8275;--danger:#bd3827;--shadow:0 12px 36px rgba(78,58,34,.10)}
 *{box-sizing:border-box}html{-webkit-text-size-adjust:100%;text-size-adjust:100%}body{margin:0;background:#f8f3e8}button,input,textarea,select{font:inherit;color:inherit}@media(max-width:800px){input,textarea,select{font-size:16px}}button{cursor:pointer}svg{width:18px;height:18px;stroke-width:1.8}.center,.auth-shell{min-height:100vh;display:grid;place-items:center}.center{gap:12px;align-content:center;color:var(--muted)}.loader{width:24px;height:24px;border:2px solid var(--line);border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}
 .auth-shell{background:radial-gradient(circle at 20% 10%,#ffe3d5 0,transparent 28%),linear-gradient(135deg,#f8f3e8,#fffaf0)}.auth-card{width:min(390px,90vw);padding:38px;background:var(--paper);border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow);display:grid;gap:16px}.brand{font-size:40px;font-weight:850;letter-spacing:-3px}.brand span{color:var(--accent)}.brand.small{font-size:29px}.auth-card p{margin:0 0 8px;color:var(--muted)}.auth-card label,.detail-form>label{display:grid;gap:7px;font-size:12px;font-weight:650;color:#756d61}.auth-card input,.detail-form input,.detail-form select{width:100%;border:1px solid var(--line);background:#fff;padding:11px;border-radius:9px;outline:none}.auth-card input:focus,.detail-form input:focus,.detail-form select:focus,.detail-form textarea:focus{border-color:var(--accent);box-shadow:0 0 0 3px rgba(241,90,41,.1)}.primary{border:0;background:var(--accent);color:#fff;padding:12px;border-radius:9px;font-weight:700;box-shadow:0 5px 12px rgba(241,90,41,.2)}.auth-card small{color:var(--danger)}
-.shell{height:100vh;display:grid;grid-template-columns:238px minmax(430px,1fr) 350px;background:var(--paper);overflow:hidden}.sidebar{border-right:1px solid var(--line);background:var(--sidebar);display:flex;flex-direction:column;min-height:0}.brand-row{height:76px;padding:0 20px;display:flex;align-items:center;justify-content:space-between}.primary-nav{display:grid;padding:4px 12px 12px;gap:3px}.primary-nav button,.settings{display:flex;align-items:center;gap:10px;border:0;background:transparent;padding:10px 12px;border-radius:9px;color:#665e52;text-align:left}.primary-nav button:hover,.list-row:hover,.folder-row>button:hover{background:rgba(255,255,255,.52)}.primary-nav button.active,.list-row.active{background:var(--accent-soft);color:#b7421e;font-weight:700}.section-title{padding:17px 17px 7px 22px;display:flex;justify-content:space-between;align-items:center;color:#958b7d;text-transform:uppercase;letter-spacing:.08em;font-size:11px;font-weight:750}.section-title>span:last-child{display:flex}.mini-icon,.row-actions button{min-width:44px;min-height:44px;border:0;background:transparent;padding:4px;color:#8e8477}.mini-icon svg,.row-actions svg{width:14px;height:14px}.folders{flex:1;min-height:0;padding:0 10px;overflow-y:auto;overflow-x:hidden;-webkit-overflow-scrolling:touch}.folder-row,.list-row{position:relative;display:flex;align-items:center;border-radius:8px}.folder-row>button,.list-row-main{flex:1;min-width:0;border:0;background:transparent;padding:8px;display:flex;align-items:center;gap:7px;color:#6d6559;text-align:left}.folder-row>button>span,.list-row-main>span{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.folder-row>button svg{width:14px}.row-actions{display:flex;position:absolute;right:0;opacity:0;pointer-events:none;transition:opacity .15s}.folder-row:hover .row-actions,.folder-row:focus-within .row-actions,.list-row:hover .row-actions,.list-row:focus-within .row-actions{opacity:1;pointer-events:auto}.list-row-main{width:100%;min-height:44px;padding:8px 7px 8px 31px;color:#665f55}.list-row.active .list-row-main{color:inherit}.list-row i{flex:0 0 8px;width:8px;height:8px;background:#d89b62;border-radius:3px}.settings{margin:auto 12px 14px}.mobile-only,.bottom,.fab{display:none}
+.shell{height:100vh;display:grid;grid-template-columns:238px minmax(430px,1fr) 350px;background:var(--paper);overflow:hidden}.shell.sidebar-collapsed{grid-template-columns:0 minmax(430px,1fr) 350px}.shell.sidebar-collapsed .sidebar{width:0;min-width:0;overflow:hidden;border-right:0;padding:0}.sidebar{border-right:1px solid var(--line);background:var(--sidebar);display:flex;flex-direction:column;min-height:0;overflow:hidden}.brand-row{height:76px;padding:0 20px;display:flex;align-items:center;justify-content:space-between}.primary-nav{display:grid;padding:4px 12px 12px;gap:3px}.primary-nav button,.settings{display:flex;align-items:center;gap:10px;border:0;background:transparent;padding:10px 12px;border-radius:9px;color:#665e52;text-align:left}.primary-nav button:hover,.list-row:hover,.folder-row>button:hover{background:rgba(255,255,255,.52)}.primary-nav button.active,.list-row.active{background:var(--accent-soft);color:#b7421e;font-weight:700}.section-title{padding:17px 17px 7px 22px;display:flex;justify-content:space-between;align-items:center;color:#958b7d;text-transform:uppercase;letter-spacing:.08em;font-size:11px;font-weight:750}.section-title>span:last-child{display:flex}.mini-icon,.row-actions button{min-width:44px;min-height:44px;border:0;background:transparent;padding:4px;color:#8e8477}.mini-icon svg,.row-actions svg{width:14px;height:14px}.folders{flex:1;min-height:0;padding:0 10px;overflow-y:auto;overflow-x:hidden;-webkit-overflow-scrolling:touch;scrollbar-width:none}.folders::-webkit-scrollbar{display:none}.folder-row,.list-row{position:relative;display:flex;align-items:center;border-radius:8px}.folder-row>button,.list-row-main{flex:1;min-width:0;border:0;background:transparent;padding:8px;display:flex;align-items:center;gap:7px;color:#6d6559;text-align:left}.folder-row>button>span,.list-row-main>span{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.folder-row>button svg{width:14px}.row-actions{display:flex;position:absolute;right:0;opacity:0;pointer-events:none;transition:opacity .15s}.folder-row:hover .row-actions,.folder-row:focus-within .row-actions,.list-row:hover .row-actions,.list-row:focus-within .row-actions{opacity:1;pointer-events:auto}.list-row-main{width:100%;min-height:44px;padding:8px 7px 8px 31px;color:#665f55}.list-row.active .list-row-main{color:inherit}.list-row i{flex:0 0 8px;width:8px;height:8px;background:#d89b62;border-radius:3px}.settings{margin:auto 12px 14px}.mobile-only,.bottom,.fab{display:none}
 main{min-width:0;padding:27px 34px 50px;overflow:auto;background:linear-gradient(rgba(255,253,248,.92),rgba(255,253,248,.92)),repeating-linear-gradient(0deg,transparent,transparent 31px,#eee3d2 32px)}.topbar{display:flex;align-items:center;gap:14px}.topbar>div{flex:1}.topbar p{margin:0;color:var(--muted);font-size:12px}.topbar h1{font-size:27px;margin:3px 0 21px;letter-spacing:-.03em}.search{margin-bottom:18px;display:flex;align-items:center;gap:8px;width:min(260px,36%);padding:8px 10px;background:#faf7f0;border:1px solid var(--line);border-radius:9px;color:var(--muted)}.search input{min-width:0;width:100%;border:0;outline:0;background:transparent}.search kbd{font-size:10px;white-space:nowrap;border:1px solid var(--line);padding:2px 4px;border-radius:4px}.quick{display:flex;align-items:center;gap:10px;background:#fff;border:1px solid var(--line);border-radius:11px;padding:7px 7px 7px 13px;box-shadow:0 2px 10px rgba(81,61,38,.05);transition:.18s}.quick:focus-within{border-color:var(--accent);box-shadow:0 0 0 3px rgba(241,90,41,.09)}.quick>svg{color:var(--accent)}.quick input{border:0;outline:0;background:transparent;min-width:0;flex:1}.quick button{border:0;border-radius:8px;background:var(--accent);color:white;padding:8px 15px;font-weight:650}.list-toolbar{height:42px;display:flex;align-items:center;gap:14px;color:var(--muted);font-size:12px}.list-toolbar label{margin-right:auto}.link{border:0;background:transparent;color:var(--accent);padding:3px;display:inline-flex;gap:3px;align-items:center}.link svg{width:14px}.task-list{transition:opacity .2s}.task-list.loading{opacity:.45}.task-row{border-left:0;--swipe-x:0px;min-height:53px;display:flex;align-items:center;gap:10px;border-bottom:1px solid var(--line);padding:4px 8px;transition:background .15s,transform .18s ease;position:relative;overflow:hidden;isolation:isolate}.task-row.swipeable{touch-action:pan-y;transform:translateX(var(--swipe-x))}.task-row.swipeable:not([style*="0px"]){transition:none}.task-row:hover,.task-row.selected{background:rgba(250,240,229,.75)}.task-row:hover{transform:translateX(calc(var(--swipe-x) + 2px))}.swipe-bg{position:absolute;z-index:-1;inset:0 auto 0 calc(-1 * var(--swipe-x));width:var(--swipe-width);min-width:0;display:flex;align-items:center;padding-left:14px;background:#e9f7ee;color:#24814f;font-size:12px;font-weight:800;white-space:nowrap;overflow:hidden}.swipe-bg.cancel{left:auto;right:var(--swipe-x);justify-content:flex-end;padding:0 14px 0 0;background:#fff2e8;color:#c65a23}.task-row.ready .swipe-bg,.habit-row.ready .swipe-bg{background:#dff3e7;color:#187142}.task-row.ready .swipe-bg.cancel,.habit-row.ready .swipe-bg.cancel{background:#ffe4d3;color:#b94716}.check{width:19px;height:19px;flex:0 0 19px;border:1.6px solid #c6baa8;background:#fff;border-radius:5px;padding:0;display:grid;place-items:center}.check svg{width:13px}.check.p1{border-color:#4b93d1}.check.p2{border-color:#d79b25}.check.p3{border-color:#dc4b30}.done .check{background:#afa595;color:white}.task-main{border:0;background:transparent;flex:1;min-width:0;text-align:left;padding:8px 0}.task-main strong{display:block;font-size:14px;font-weight:590;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.done .task-main strong{text-decoration:line-through;color:#9b9388}.meta{display:flex;align-items:center;gap:9px;color:#9b9286;font-size:11px;margin-top:3px}.meta span{display:flex;align-items:center;gap:3px}.meta svg{width:12px}.priority{font-size:10px;font-weight:750;padding:3px 6px;border-radius:5px}.priority.p1{color:#3f80ba;background:#e5f2fc}.priority.p2{color:#a56b05;background:#fff1cb}.priority.p3{color:#bd3827;background:#fde2dc}.icon,.ghost{min-width:44px;min-height:44px;border:0;background:transparent;display:grid;place-items:center;padding:5px;border-radius:6px}.mobile-only{display:none}.ghost{opacity:0;color:#9d9387}.task-row:hover .ghost{opacity:1}.ghost:hover{color:var(--danger);background:#fce7e2}.restore{display:flex;align-items:center;gap:5px;border:1px solid var(--line);background:#fff;border-radius:7px;padding:6px 8px;font-size:12px}.restore svg{width:14px}.subtask{padding-left:53px;min-height:42px;color:#6d655b}.subtask>svg{width:13px;color:#bbb0a2}.empty{min-height:300px;display:grid;place-items:center;align-content:center;gap:8px;color:#aaa094;text-align:center}.empty>svg{width:38px;height:38px;color:#d8cabb}.empty b{color:#6f675c}.empty span{font-size:13px}
 .detail{min-width:0;border-left:1px solid var(--line);background:#faf7f0;overflow:auto}.detail-head{height:57px;display:flex;align-items:center;justify-content:space-between;padding:0 21px;border-bottom:1px solid var(--line);font-size:12px;font-weight:700;color:#80766a;text-transform:uppercase;letter-spacing:.08em}.paper{margin:22px;padding:28px 20px;min-height:180px;background:#fff;border:1px solid var(--line);border-radius:11px;box-shadow:0 4px 18px rgba(76,57,34,.05);display:grid;place-items:center;align-content:center;text-align:center;color:#8f8578}.paper svg{width:32px;height:32px;color:#ceb8a4;margin-bottom:12px}.paper b{color:#625b50}.paper p{font-size:13px;line-height:1.6}.detail-form{padding:19px;display:grid;gap:15px}.detail-title{display:flex;align-items:flex-start;gap:10px}.check.large{margin-top:8px;width:22px;height:22px;flex-basis:22px}.detail-title textarea{flex:1;border:0;background:transparent;resize:none;outline:none;font-size:19px;line-height:1.4;font-weight:700}.detail-form>label{grid-template-columns:80px 1fr;align-items:center}.detail-form>label input,.detail-form>label select{padding:8px}.field{display:grid;gap:7px}.field-label{display:flex;justify-content:space-between;align-items:center;font-size:12px;font-weight:700;color:#756d61}.hint{font-size:12px;color:#a49a8d}.markdown .field-label>span:last-child{display:flex;background:#eee7dc;padding:2px;border-radius:6px}.markdown .field-label button{border:0;background:transparent;padding:4px 8px;border-radius:5px;font-size:11px}.markdown .field-label button.active{background:#fff;color:var(--accent)}.markdown textarea{border:1px solid var(--line);background:#fff;border-radius:9px;padding:11px;resize:vertical;outline:none;font:13px/1.6 ui-monospace,SFMono-Regular,Menlo,monospace}.markdown-preview{min-height:160px;padding:10px 12px;background:#fff;border:1px solid var(--line);border-radius:9px;font-size:13px;line-height:1.65;overflow-wrap:anywhere}.markdown-preview h1{font-size:20px}.markdown-preview h2{font-size:16px}.markdown-preview p{margin:8px 0}.markdown-preview code{background:#f2ece2;padding:2px 4px;border-radius:4px}.markdown-preview a{color:var(--accent)}.subtasks{display:grid;gap:5px}.subtask-detail{display:flex;align-items:center;gap:8px;border:0;background:#fff;padding:8px;border-radius:7px;text-align:left}.subtask-detail .check{pointer-events:none}.strike{text-decoration:line-through;color:var(--muted)}.detail-actions{display:flex;justify-content:space-between;align-items:center;padding-top:10px;border-top:1px solid var(--line)}.secondary{border:1px solid var(--line);background:#fff;padding:8px 11px;border-radius:8px;font-weight:650}.danger-text{border:0;background:transparent;color:var(--danger);display:flex;align-items:center;gap:5px;font-size:12px}.danger-text svg{width:14px}
 .toast,.error-toast{position:fixed;z-index:50;left:50%;bottom:24px;transform:translateX(-50%);background:#322d28;color:#fff;border-radius:9px;padding:10px 15px;box-shadow:var(--shadow);font-size:13px}.error-toast{background:var(--danger);display:flex;align-items:center;gap:10px}.error-toast button{border:0;background:transparent;color:#fff;padding:0}.toast-enter-active,.toast-leave-active{transition:.2s}.toast-enter-from,.toast-leave-to{opacity:0;transform:translate(-50%,8px)}
diff --git a/frontend/src/style.test.ts b/frontend/src/style.test.ts
index c89a2f1..17b23ff 100644
--- a/frontend/src/style.test.ts
+++ b/frontend/src/style.test.ts
@@ -35,6 +35,19 @@ describe('mobile touch targets', () => {
   })
 })
 
+describe('desktop sidebar collapse & folder scrollbar', () => {
+  it('lets the top menu collapse the desktop sidebar', () => {
+    expect(app).toContain('sidebar-collapsed')
+    expect(app).toContain('toggleSidebar')
+    expect(css).toContain('.shell.sidebar-collapsed{grid-template-columns:0 minmax(430px,1fr) 350px}')
+  })
+
+  it('hides the folders scrollbar while staying scrollable', () => {
+    expect(css).toContain('scrollbar-width:none')
+    expect(css).toContain('.folders::-webkit-scrollbar{display:none}')
+  })
+})
+
 describe('sidebar layout', () => {
   it('switches to the compact layout before the desktop grid can be clipped', () => {
     expect(css).toContain('@media(max-width:930px){.shell')