diff --git a/apps/web/components/AppShell.tsx b/apps/web/components/AppShell.tsx
index c7e6f80..b6fa456 100644
--- a/apps/web/components/AppShell.tsx
+++ b/apps/web/components/AppShell.tsx
@@ -18,6 +18,9 @@ interface AppShellProps {
   projectId?: string;
   // 当前激活的项目级入口键（用于高亮）。
   activeNav?: ActiveNav;
+  // 专注写作模式（P3-4）：隐藏桌面左侧图标导航以加宽正文；顶栏汉堡/命令面板仍可达导航。
+  // 缺省 false → 其余页面外观不变（加法式可选项）。
+  hideNav?: boolean;
 }
 
 // 全局外壳：顶栏(64px) + 左导航 + 主区（UX §5.1）。
@@ -27,6 +30,7 @@ export function AppShell({
   subtitle,
   projectId,
   activeNav,
+  hideNav = false,
 }: AppShellProps) {
   return (
     <div
@@ -80,7 +84,7 @@ export function AppShell({
         </nav>
       </header>
       <div className="flex">
-        <LeftNav projectId={projectId} activeNav={activeNav} />
+        {hideNav ? null : <LeftNav projectId={projectId} activeNav={activeNav} />}
         <main
           id="main"
           tabIndex={-1}
diff --git a/apps/web/components/workbench/AiToolbar.tsx b/apps/web/components/workbench/AiToolbar.tsx
new file mode 100644
index 0000000..e707122
--- /dev/null
+++ b/apps/web/components/workbench/AiToolbar.tsx
@@ -0,0 +1,309 @@
+"use client";
+
+import { useEffect, useId, useRef, useState } from "react";
+import {
+  ChevronDown,
+  HelpCircle,
+  PenLine,
+  RefreshCw,
+  Sparkles,
+  Square,
+  Wand2,
+  WrapText,
+} from "lucide-react";
+
+import { Button } from "@/components/ui/Button";
+import { Eyebrow } from "@/components/ui/Eyebrow";
+import { SectionHeader } from "@/components/ui/SectionHeader";
+import { StatusNote } from "@/components/ui/StatusNote";
+import { TextArea } from "@/components/ui/TextArea";
+import { PLOT_PRESETS, STYLE_PRESETS, type Preset } from "@/lib/workbench/directive";
+import { buttonClass, focusRing } from "@/lib/ui/variants";
+
+interface DirectivePanelProps {
+  directive: string;
+  onDirectiveChange: (value: string) => void;
+  presetIds: readonly string[];
+  onTogglePreset: (id: string) => void;
+  // 空章默认展开（新手最需要看到输入框的时机）；满章默认收起以让出编辑视野。
+  defaultOpen: boolean;
+  // 发送键 = 写本章：把已选文风/剧情 + 自定义要求组装后逐字流式写进正文（不改成聊天气泡）。
+  streaming: boolean;
+  onWrite: () => void;
+  onStop: () => void;
+}
+
+// 本章写作指令面板（P0-2 / P3-3 提升）：正文正上方常驻的「和 AI 说话」输入条。
+// 眉题「和 AI 说话」+ 主标题「告诉 AI 这章想怎么写」+ HITL 微文案 +「?这是什么」常驻可见；
+// 主 CTA「写本章」突出（md 尺寸、独占右侧），空章默认展开露出输入框。
+// 发送键即「写本章」，沿用 composeDirective + 文风/剧情 chips + 流式打字机写进正文。
+export function DirectivePanel({
+  directive,
+  onDirectiveChange,
+  presetIds,
+  onTogglePreset,
+  defaultOpen,
+  streaming,
+  onWrite,
+  onStop,
+}: DirectivePanelProps) {
+  const panelId = useId();
+  const [open, setOpen] = useState(defaultOpen);
+  const activeCount = presetIds.length + (directive.trim().length > 0 ? 1 : 0);
+  return (
+    <section className="border-b border-line bg-panel px-4 py-4 sm:px-6">
+      <div className="flex items-start justify-between gap-4">
+        <div className="min-w-0">
+          <Eyebrow className="mb-1">和 AI 说话</Eyebrow>
+          <button
+            type="button"
+            onClick={() => setOpen((v) => !v)}
+            aria-expanded={open}
+            aria-controls={panelId}
+            className={`group flex min-w-0 cursor-pointer items-center gap-2 rounded text-left font-serif text-title-md text-ink transition-colors duration-fast ease-standard hover:text-cinnabar ${focusRing}`}
+          >
+            <ChevronDown
+              className={`h-4 w-4 shrink-0 text-muted-soft transition-transform duration-fast ease-standard group-hover:text-cinnabar ${
+                open ? "rotate-180" : ""
+              }`}
+              aria-hidden="true"
+            />
+            <span className="truncate">告诉 AI 这章想怎么写</span>
+          </button>
+        </div>
+        <div className="flex shrink-0 items-center gap-2">
+          {activeCount > 0 ? (
+            <span className="hidden rounded-full border border-line bg-bg px-2.5 py-0.5 text-2xs text-ink-soft sm:inline">
+              {activeCount} 项指令
+            </span>
+          ) : null}
+          {/* 常驻主 CTA = 写本章：始终可见（折叠时也在），md 尺寸凸显为本条主动作，逐字流式写进正文。 */}
+          {streaming ? (
+            <Button onClick={onStop} variant="danger" size="md">
+              <Square className="h-4 w-4" aria-hidden="true" />
+              停
+            </Button>
+          ) : (
+            <Button onClick={onWrite} variant="primary" size="md">
+              <PenLine className="h-4 w-4" aria-hidden="true" />
+              写本章
+              <span className="text-2xs font-normal text-panel/75">
+                整章·从头写
+              </span>
+            </Button>
+          )}
+          <HitlHelp />
+        </div>
+      </div>
+      <p className="mt-2 text-caption text-muted-soft">
+        AI 给草稿，你决定采不采用，原文永远你说了算。
+      </p>
+      {open ? (
+        <div id={panelId} className="mt-4 space-y-4">
+          <SectionHeader
+            title="你的写作要求"
+            description="选文风、点剧情需求、写自己的要求，只影响本次生成。"
+          />
+          <PresetGroup
+            label="文风"
+            presets={STYLE_PRESETS}
+            presetIds={presetIds}
+            onToggle={onTogglePreset}
+          />
+          <PresetGroup
+            label="剧情需求"
+            presets={PLOT_PRESETS}
+            presetIds={presetIds}
+            onToggle={onTogglePreset}
+          />
+          <label className="block">
+            <span className="mb-1 block text-sm text-ink-soft">自己的要求</span>
+            <TextArea
+              value={directive}
+              onChange={(e) => onDirectiveChange(e.target.value)}
+              rows={2}
+              placeholder="写点要求，AI 更懂你（留空则按大纲写）"
+            />
+          </label>
+          {activeCount > 0 ? (
+            <StatusNote variant="info">
+              写本章时会把已选文风/剧情预设和你的要求合并进本次生成请求。
+            </StatusNote>
+          ) : null}
+        </div>
+      ) : null}
+    </section>
+  );
+}
+
+interface AiVerbsRowProps {
+  streaming: boolean;
+  onContinue: () => void;
+  onRefineSelection: () => void;
+  onRewrite: () => void;
+  onToolbox: () => void;
+}
+
+// 「或让 AI:」次级动作行（P1-1 / P3-3）：常驻贴在中央输入条下方，把续写/润色/整章重写/工具箱
+// 归为「同一个 AI 的其它用法」（act-on-chapter 与导航分家）。用较浅面色 + 更软分隔成组，
+// 与上方主指令条拉开层级。每个动词带可见范围提示（P1-4）。生成中禁用（避免与流式写章并发）。
+export function AiVerbsRow({
+  streaming,
+  onContinue,
+  onRefineSelection,
+  onRewrite,
+  onToolbox,
+}: AiVerbsRowProps) {
+  return (
+    <div className="flex flex-wrap items-center gap-x-3 gap-y-2 border-b border-line-soft bg-surface-soft px-4 py-2.5 sm:px-6">
+      <span className="text-eyebrow uppercase tracking-wide text-muted-soft">
+        或让 AI
+      </span>
+      <VerbButton
+        icon={WrapText}
+        label="续写"
+        hint="接着往下写"
+        disabled={streaming}
+        onClick={onContinue}
+      />
+      <VerbButton
+        icon={Wand2}
+        label="润色选段"
+        hint="选中段·打磨"
+        disabled={streaming}
+        onClick={onRefineSelection}
+      />
+      <VerbButton
+        icon={RefreshCw}
+        label="整章重写"
+        hint="整章·基于现有重写"
+        disabled={streaming}
+        onClick={onRewrite}
+      />
+      <VerbButton
+        icon={Sparkles}
+        label="工具箱"
+        disabled={streaming}
+        onClick={onToolbox}
+      />
+    </div>
+  );
+}
+
+interface VerbButtonProps {
+  icon: typeof WrapText;
+  label: string;
+  // 可见（非 hover-only）范围提示：让作者点前就能预判对草稿的影响（P1-4）。工具箱无范围提示。
+  hint?: string;
+  disabled: boolean;
+  onClick: () => void;
+}
+
+function VerbButton({ icon: Icon, label, hint, disabled, onClick }: VerbButtonProps) {
+  return (
+    <Button onClick={onClick} disabled={disabled} variant="secondary" size="sm">
+      <Icon className="h-4 w-4" aria-hidden="true" />
+      {label}
+      {hint ? <span className="text-2xs text-ink-soft">{hint}</span> : null}
+    </Button>
+  );
+}
+
+// 「?这是什么」：常驻、可再发现的说明（非一次性 coach）——解释「和 AI 说话」的闭环。
+// 按钮 + 轻量弹层，Esc / 点击外部关闭，还原焦点。
+function HitlHelp() {
+  const [open, setOpen] = useState(false);
+  const popId = useId();
+  const rootRef = useRef<HTMLDivElement>(null);
+  const buttonRef = useRef<HTMLButtonElement>(null);
+
+  useEffect(() => {
+    if (!open) return;
+    const onKeyDown = (e: KeyboardEvent): void => {
+      if (e.key === "Escape") {
+        setOpen(false);
+        buttonRef.current?.focus();
+      }
+    };
+    const onPointerDown = (e: PointerEvent): void => {
+      const target = e.target;
+      if (target instanceof Node && !rootRef.current?.contains(target)) {
+        setOpen(false);
+      }
+    };
+    window.addEventListener("keydown", onKeyDown);
+    window.addEventListener("pointerdown", onPointerDown);
+    return () => {
+      window.removeEventListener("keydown", onKeyDown);
+      window.removeEventListener("pointerdown", onPointerDown);
+    };
+  }, [open]);
+
+  return (
+    <div ref={rootRef} className="relative">
+      <button
+        ref={buttonRef}
+        type="button"
+        aria-haspopup="dialog"
+        aria-expanded={open}
+        aria-controls={popId}
+        onClick={() => setOpen((v) => !v)}
+        className={buttonClass({
+          variant: "ghost",
+          size: "sm",
+          className: "gap-1 text-xs text-ink-soft",
+        })}
+      >
+        <HelpCircle className="h-4 w-4" aria-hidden="true" />
+        这是什么
+      </button>
+      {open ? (
+        <div
+          id={popId}
+          role="dialog"
+          aria-label="怎么和 AI 说话"
+          className="absolute right-0 z-30 mt-2 w-72 max-w-[80vw] rounded-lg border border-line bg-panel p-4 text-sm text-ink-soft shadow-paper"
+        >
+          <p className="mb-1 font-serif text-title-md text-ink">怎么和 AI 说话</p>
+          <p className="leading-6">
+            在这条写下要求，点「写本章」——AI 会把草稿逐字写进正文。草稿随时能改；
+            满意了去「审稿」验收。原文永远你说了算。
+          </p>
+        </div>
+      ) : null}
+    </div>
+  );
+}
+
+interface PresetGroupProps {
+  label: string;
+  presets: readonly Preset[];
+  presetIds: readonly string[];
+  onToggle: (id: string) => void;
+}
+
+// 一组预设 chips（文风 / 剧情需求）：点选 toggle，选中高亮。id 统一进 presetIds。
+function PresetGroup({ label, presets, presetIds, onToggle }: PresetGroupProps) {
+  return (
+    <div>
+      <p className="mb-1 text-sm text-ink-soft">{label}</p>
+      <div className="flex flex-wrap gap-2" role="group" aria-label={label}>
+        {presets.map((preset) => {
+          const active = presetIds.includes(preset.id);
+          return (
+            <Button
+              key={preset.id}
+              type="button"
+              aria-pressed={active}
+              onClick={() => onToggle(preset.id)}
+              variant={active ? "outline" : "secondary"}
+              size="sm"
+            >
+              {preset.label}
+            </Button>
+          );
+        })}
+      </div>
+    </div>
+  );
+}
diff --git a/apps/web/components/workbench/ChapterAssistant.tsx b/apps/web/components/workbench/ChapterAssistant.tsx
index 5f13162..c8359ca 100644
--- a/apps/web/components/workbench/ChapterAssistant.tsx
+++ b/apps/web/components/workbench/ChapterAssistant.tsx
@@ -1,10 +1,19 @@
 "use client";
 
-import { Minus, Pin, PinOff, Plus, RotateCcw, Undo2, X } from "lucide-react";
+import type { ReactNode } from "react";
+import {
+  Minus,
+  Pin,
+  PinOff,
+  Plus,
+  RotateCcw,
+  Sparkles,
+  Undo2,
+  X,
+} from "lucide-react";
 
 import { ThinkingIndicator } from "@/components/ThinkingIndicator";
 import { Button } from "@/components/ui/Button";
-import { SectionHeader } from "@/components/ui/SectionHeader";
 import { StatusNote } from "@/components/ui/StatusNote";
 import { buttonClass } from "@/lib/ui/variants";
 import {
@@ -35,6 +44,25 @@ export function ChapterAssistant({ projectId, chapterNo }: ChapterAssistantProps
   );
 }
 
+// 窄栏小标题（P3-5）：font-sans + eyebrow 字号/正字距（对齐 Eyebrow 眉题的视觉），
+// 但保留 <h3> 语义（不降级为 <p>，守住标题大纲 a11y）。可带右侧行内控件（如步进器）。
+function PanelLabel({
+  children,
+  action,
+}: {
+  children: ReactNode;
+  action?: ReactNode;
+}) {
+  return (
+    <div className="flex items-start justify-between gap-3">
+      <h3 className="font-sans text-eyebrow uppercase tracking-wide text-muted-soft">
+        {children}
+      </h3>
+      {action ? <div className="shrink-0">{action}</div> : null}
+    </div>
+  );
+}
+
 export function AssistantContent({ projectId, chapterNo }: ChapterAssistantProps) {
   const injection = useInjection(projectId, chapterNo);
   const data = injection.data;
@@ -43,21 +71,17 @@ export function AssistantContent({ projectId, chapterNo }: ChapterAssistantProps
 
   return (
     <div className="px-4">
-      <SectionHeader
-        title="本章参考"
-        action={
-          injection.saving ? (
-            <ThinkingIndicator
-              label="保存中"
-              className="text-xs text-ink-soft"
-            />
-          ) : null
-        }
-      />
+      <div className="flex items-center justify-between gap-2">
+        <h2 className="font-sans text-title-md font-medium text-ink">
+          本章参考
+        </h2>
+        {injection.saving ? (
+          <ThinkingIndicator label="保存中" className="text-xs text-ink-soft" />
+        ) : null}
+      </div>
 
-      <section className="mt-4">
-        <SectionHeader
-          title="AI 写这章会参考"
+      <section className="mt-5">
+        <PanelLabel
           action={
             data ? (
               <RecentStepper
@@ -67,10 +91,12 @@ export function AssistantContent({ projectId, chapterNo }: ChapterAssistantProps
               />
             ) : null
           }
-        />
+        >
+          AI 写这章会参考
+        </PanelLabel>
 
         {injection.loading ? (
-          <p className="mt-2 text-xs text-ink-soft">加载参考信息…</p>
+          <p className="mt-2 text-caption text-ink-soft">加载参考信息…</p>
         ) : !data ? (
           // 首次加载失败：data 仍为空 → 满屏错误框 + 重试。
           <StatusNote variant="danger" className="mt-2 text-xs" title="参考信息暂不可用">
@@ -113,11 +139,15 @@ export function AssistantContent({ projectId, chapterNo }: ChapterAssistantProps
             ) : null}
 
             {selected.length === 0 ? (
-              <p className="mt-2 rounded border border-dashed border-line bg-bg p-3 text-xs text-ink-soft">
-                这一章 AI 还没有要参考的设定/角色。可在大纲里点名，或从下方「已排除」里恢复。
-              </p>
+              // 空态占位（不加标题，避免在 h3 子小节内注入 h2 破坏标题大纲）。
+              <div className="mt-2 flex flex-col items-center gap-2 py-4 text-center">
+                <Sparkles className="h-5 w-5 text-muted-soft" aria-hidden="true" />
+                <p className="max-w-xs text-caption leading-6 text-ink-soft">
+                  这一章 AI 还没要参考的设定/角色。可在大纲里点名，或从下方「已排除」里恢复。
+                </p>
+              </div>
             ) : (
-              <ul className="mt-2 space-y-2">
+              <ul className="mt-3 space-y-2">
                 {selected.map((entity) => (
                   <EntityRow
                     key={`${entity.kind}:${entity.name}`}
@@ -137,9 +167,9 @@ export function AssistantContent({ projectId, chapterNo }: ChapterAssistantProps
         )}
 
         {excluded.length > 0 ? (
-          <div className="mt-3">
-            <SectionHeader title="已排除（本章不参考）" />
-            <ul className="mt-1 space-y-1">
+          <div className="mt-4">
+            <PanelLabel>已排除（本章不参考）</PanelLabel>
+            <ul className="mt-2 space-y-1">
               {excluded.map((ref) => (
                 <ExcludedRow
                   key={`${ref.kind}:${ref.name}`}
@@ -153,11 +183,11 @@ export function AssistantContent({ projectId, chapterNo }: ChapterAssistantProps
         ) : null}
       </section>
 
-      <section className="mt-6">
-        <SectionHeader
-          title="写完后检查"
-          description="写完这章，AI 会把一致性、伏笔、文风、节奏各查一遍。到左栏或底栏的「审稿」逐条过。"
-        />
+      <section className="mt-6 border-t border-line-soft pt-5">
+        <PanelLabel>写完后检查</PanelLabel>
+        <p className="mt-1.5 text-caption leading-6 text-ink-soft">
+          写完这章，AI 会把一致性、伏笔、文风、节奏各查一遍。到左栏或底栏的「审稿」逐条过。
+        </p>
       </section>
     </div>
   );
diff --git a/apps/web/components/workbench/ChapterList.tsx b/apps/web/components/workbench/ChapterList.tsx
index 07653f7..1d534ed 100644
--- a/apps/web/components/workbench/ChapterList.tsx
+++ b/apps/web/components/workbench/ChapterList.tsx
@@ -29,7 +29,7 @@ export function ChapterList({
   if (collapsed) {
     return (
       <aside
-        className="hidden shrink-0 border-r border-line bg-panel py-4 xl:block"
+        className="hidden shrink-0 border-r border-line bg-surface-soft py-4 xl:block"
         aria-label="目录（已收起）"
       >
         <button
@@ -38,7 +38,7 @@ export function ChapterList({
           aria-expanded={false}
           aria-label="展开目录"
           title="展开目录"
-          className={`mx-auto flex h-8 w-8 items-center justify-center rounded text-ink-soft transition-colors hover:bg-[var(--color-cinnabar-wash)] hover:text-cinnabar ${focusRing}`}
+          className={`mx-auto flex h-8 w-8 items-center justify-center rounded-md border border-line bg-panel text-ink-soft transition-colors duration-fast ease-standard hover:border-cinnabar hover:bg-[var(--color-cinnabar-wash)] hover:text-cinnabar ${focusRing}`}
         >
           <PanelLeftOpen className="h-4 w-4" aria-hidden="true" />
         </button>
@@ -46,7 +46,7 @@ export function ChapterList({
     );
   }
   return (
-    <aside className="hidden border-r border-line bg-panel py-4 xl:block">
+    <aside className="hidden border-r border-line bg-surface-soft py-4 xl:block">
       <ChapterListContent
         projectId={projectId}
         chapters={chapters}
@@ -73,7 +73,7 @@ export function ChapterListContent({
   return (
     <>
       <div className="flex items-center justify-between px-4">
-        <h2 className="text-xs font-semibold uppercase tracking-wide text-ink-soft">
+        <h2 className="font-sans text-eyebrow uppercase tracking-wide text-muted-soft">
           目录
         </h2>
         {onCollapse ? (
@@ -82,7 +82,7 @@ export function ChapterListContent({
             onClick={onCollapse}
             aria-label="收起目录"
             title="收起目录"
-            className={`flex h-6 w-6 items-center justify-center rounded text-ink-soft transition-colors hover:bg-[var(--color-cinnabar-wash)] hover:text-cinnabar ${focusRing}`}
+            className={`flex h-7 w-7 items-center justify-center rounded-md border border-line bg-panel text-ink-soft transition-colors duration-fast ease-standard hover:border-cinnabar hover:bg-[var(--color-cinnabar-wash)] hover:text-cinnabar ${focusRing}`}
           >
             <PanelLeftClose className="h-4 w-4" aria-hidden="true" />
           </button>
@@ -98,8 +98,8 @@ export function ChapterListContent({
                 aria-current={active ? "page" : undefined}
                 className={
                   active
-                    ? "flex flex-col gap-0.5 border-l-2 border-cinnabar bg-[var(--color-cinnabar-wash)] px-4 py-2 text-sm text-cinnabar"
-                    : "flex flex-col gap-0.5 border-l-2 border-transparent px-4 py-2 text-sm text-ink hover:border-cinnabar hover:text-cinnabar"
+                    ? `flex flex-col gap-0.5 border-l-2 border-cinnabar bg-[var(--color-cinnabar-wash)] px-4 py-2 text-sm font-medium text-cinnabar transition-colors duration-fast ease-standard ${focusRing}`
+                    : `flex flex-col gap-0.5 border-l-2 border-transparent px-4 py-2 text-sm text-ink transition-colors duration-fast ease-standard hover:border-line-soft hover:bg-panel/60 hover:text-cinnabar ${focusRing}`
                 }
               >
                 <span className="flex items-center gap-2">
diff --git a/apps/web/components/workbench/MobileContextBar.tsx b/apps/web/components/workbench/MobileContextBar.tsx
new file mode 100644
index 0000000..99b3848
--- /dev/null
+++ b/apps/web/components/workbench/MobileContextBar.tsx
@@ -0,0 +1,49 @@
+"use client";
+
+import type { RefObject } from "react";
+import { PanelLeft, PanelRight } from "lucide-react";
+
+import { Button } from "@/components/ui/Button";
+
+interface MobileContextBarProps {
+  chapterNo: number;
+  onOpenChapters: () => void;
+  onOpenAssistant: () => void;
+  chapterTriggerRef: RefObject<HTMLButtonElement | null>;
+  assistantTriggerRef: RefObject<HTMLButtonElement | null>;
+}
+
+// 窄屏/中屏顶部上下文条：目录 / 本章参考经抽屉触达；≥xl 直显三栏、此条隐藏。
+export function MobileContextBar({
+  chapterNo,
+  onOpenChapters,
+  onOpenAssistant,
+  chapterTriggerRef,
+  assistantTriggerRef,
+}: MobileContextBarProps) {
+  return (
+    <div className="flex items-center justify-between gap-2 border-b border-line bg-panel px-4 py-2 xl:hidden">
+      <Button
+        ref={chapterTriggerRef}
+        onClick={onOpenChapters}
+        variant="secondary"
+        size="sm"
+      >
+        <PanelLeft className="h-4 w-4" aria-hidden="true" />
+        目录
+      </Button>
+      <span className="min-w-0 truncate font-mono text-xs text-ink-soft">
+        第 {chapterNo} 章
+      </span>
+      <Button
+        ref={assistantTriggerRef}
+        onClick={onOpenAssistant}
+        variant="secondary"
+        size="sm"
+      >
+        <PanelRight className="h-4 w-4" aria-hidden="true" />
+        助手
+      </Button>
+    </div>
+  );
+}
diff --git a/apps/web/components/workbench/Workbench.tsx b/apps/web/components/workbench/Workbench.tsx
index b84d961..2970de4 100644
--- a/apps/web/components/workbench/Workbench.tsx
+++ b/apps/web/components/workbench/Workbench.tsx
@@ -1,32 +1,11 @@
 "use client";
 
-import Link from "next/link";
-import { useEffect, useId, useRef, useState, type RefObject } from "react";
-import {
-  BookMarked,
-  ChevronDown,
-  ClipboardCheck,
-  FileText,
-  HelpCircle,
-  MessagesSquare,
-  PanelLeft,
-  PanelRight,
-  PenLine,
-  RefreshCw,
-  Sparkles,
-  Square,
-  Wand2,
-  WrapText,
-} from "lucide-react";
+import { useEffect, useRef, useState } from "react";
 
 import { AppShell } from "@/components/AppShell";
 import { Drawer } from "@/components/Drawer";
-import { ThinkingIndicator } from "@/components/ThinkingIndicator";
 import { useToast } from "@/components/Toast";
-import { Button } from "@/components/ui/Button";
-import { SectionHeader } from "@/components/ui/SectionHeader";
 import { StatusNote } from "@/components/ui/StatusNote";
-import { TextArea } from "@/components/ui/TextArea";
 import type { ProjectResponse } from "@/lib/api/types";
 import { friendlyError } from "@/lib/errors/messages";
 import { useAutosave } from "@/lib/autosave/useAutosave";
@@ -35,14 +14,8 @@ import {
   WORKBENCH_CHAPTER_NO,
   type ChapterEntry,
 } from "@/lib/workbench/chapter";
-import {
-  composeDirective,
-  PLOT_PRESETS,
-  STYLE_PRESETS,
-  type Preset,
-} from "@/lib/workbench/directive";
+import { composeDirective } from "@/lib/workbench/directive";
 import { applyRefinement } from "@/lib/workbench/refineApply";
-import { buttonClass, focusRing } from "@/lib/ui/variants";
 import { ChapterList, ChapterListContent } from "./ChapterList";
 import { ChapterAssistant, AssistantContent } from "./ChapterAssistant";
 import { Editor, type EditorSelection } from "./Editor";
@@ -50,7 +23,7 @@ import { RefinePanel } from "./RefinePanel";
 import { ContinuePanel } from "./ContinuePanel";
 import { InlineToolbox } from "./InlineToolbox";
 import { ChapterRewritePanel } from "./ChapterRewritePanel";
-import { ContextDrawer, CONTEXT_DRAWER_ENABLED } from "./ContextDrawer";
+import { ContextDrawer } from "./ContextDrawer";
 import {
   AiConversationDrawer,
   AI_CONVERSATION_ENABLED,
@@ -60,6 +33,10 @@ import { GENRES } from "@/lib/wizard/wizard";
 import { useGenreGate, toGenreDirective } from "@/lib/workbench/useGenreGate";
 import { useAiConversation } from "@/lib/workbench/useAiConversation";
 import { useChapterListCollapse } from "@/lib/workbench/useChapterListCollapse";
+import { useFocusMode } from "@/lib/workbench/useFocusMode";
+import { DirectivePanel, AiVerbsRow } from "./AiToolbar";
+import { MobileContextBar } from "./MobileContextBar";
+import { Toolbar } from "./WorkbenchToolbar";
 
 interface WorkbenchProps {
   project: ProjectResponse;
@@ -107,6 +84,8 @@ export function Workbench({
   const conversation = useAiConversation(project.id, chapterNo);
   // P2-2：桌面「目录」列可收起（记忆状态）；收起时把宽让给正文，窄轨留一个展开入口。
   const chapterList = useChapterListCollapse();
+  // P3-4：专注写作开关（记忆状态）——开启隐藏左侧图标导航 + 目录 TOC，让宽给正文。
+  const focusMode = useFocusMode();
   const conversationTriggerRef = useRef<HTMLButtonElement>(null);
   const toast = useToast();
   const autosave = useAutosave(project.id, chapterNo, initialText);
@@ -116,6 +95,8 @@ export function Workbench({
   const chapterTriggerRef = useRef<HTMLButtonElement>(null);
   const assistantTriggerRef = useRef<HTMLButtonElement>(null);
   const contextTriggerRef = useRef<HTMLButtonElement>(null);
+  // P3-7 流式跟随：正文滚动容器引用（纯展示层，不触碰 SSE/流式数据）。
+  const editorScrollRef = useRef<HTMLDivElement>(null);
 
   // 流式 token 累积进编辑器（打字机）；停止/结束后已生成部分留在草稿。
   useEffect(() => {
@@ -132,6 +113,15 @@ export function Workbench({
     }
   }, [stream.state.phase, stream.state.text, autosave]);
 
+  // P3-7 流式跟随：流式且正文增长时把滚动容器贴到底，让新生成的段落保持可见。
+  // 纯展示层：只读既有 text/streaming 展示态，瞬时定位（无动画，天然尊重 prefers-reduced-motion）。
+  useEffect(() => {
+    if (!stream.isStreaming) return;
+    const el = editorScrollRef.current;
+    if (!el) return;
+    el.scrollTop = el.scrollHeight;
+  }, [text, stream.isStreaming]);
+
   // 题材 + 三槽指令合并为一条写章指令（题材前置）；effectiveGenre 无 → 仅原指令。
   const startWrite = (effectiveGenre: string | null): void => {
     const base = composeDirective(directive, presetIds);
@@ -271,6 +261,13 @@ export function Workbench({
   const wordCount = text.replace(/\s+/g, "").length;
   const closePanel = (): void => setMobilePanel(null);
 
+  // 桌面栅格列宽：专注模式撤掉目录 TOC 列（仅正文 + 右栏）；否则按目录列收起/展开取宽。
+  const gridCols = focusMode.focus
+    ? "xl:grid-cols-[1fr_18rem]"
+    : chapterList.collapsed
+      ? "xl:grid-cols-[2.75rem_1fr_18rem]"
+      : "xl:grid-cols-[12rem_1fr_18rem]";
+
   // 流式里程碑播报（仅终结句，非逐 token）：完成/停止/失败时写入 role=status 区。
   const liveMessage = ((): string => {
     switch (stream.state.phase) {
@@ -294,21 +291,20 @@ export function Workbench({
       subtitle={`第 ${chapterNo} 章`}
       projectId={project.id}
       activeNav="write"
+      hideNav={focusMode.focus}
     >
       <div
-        className={`grid min-h-[calc(100vh-var(--chrome,4rem))] grid-cols-1 xl:h-[calc(100vh-var(--chrome,4rem))] ${
-          chapterList.collapsed
-            ? "xl:grid-cols-[2.75rem_1fr_18rem]"
-            : "xl:grid-cols-[12rem_1fr_18rem]"
-        }`}
+        className={`grid min-h-[calc(100vh-var(--chrome,4rem))] grid-cols-1 xl:h-[calc(100vh-var(--chrome,4rem))] ${gridCols}`}
       >
-        <ChapterList
-          projectId={project.id}
-          chapters={chapters}
-          currentChapterNo={chapterNo}
-          collapsed={chapterList.collapsed}
-          onToggle={chapterList.toggle}
-        />
+        {focusMode.focus ? null : (
+          <ChapterList
+            projectId={project.id}
+            chapters={chapters}
+            currentChapterNo={chapterNo}
+            collapsed={chapterList.collapsed}
+            onToggle={chapterList.toggle}
+          />
+        )}
 
         <section className="flex min-w-0 flex-col bg-bg">
           <MobileContextBar
@@ -386,7 +382,7 @@ export function Workbench({
               onClose={() => setRewriteOpen(false)}
             />
           ) : null}
-          <div className="flex-1 overflow-auto px-6 py-8">
+          <div ref={editorScrollRef} className="flex-1 overflow-auto px-6 py-8">
             {chapters.length === 0 ? (
               <StatusNote variant="info" className="mb-4">
                 尚无大纲，将按设定自由生成。
@@ -409,6 +405,8 @@ export function Workbench({
             streamError={stream.state.error}
             liveMessage={liveMessage}
             onStop={stream.stop}
+            focus={focusMode.focus}
+            onToggleFocus={focusMode.toggle}
             onOpenContext={() => setContextOpen(true)}
             contextTriggerRef={contextTriggerRef}
             onOpenConversation={() => setConversationOpen(true)}
@@ -467,471 +465,3 @@ export function Workbench({
     </AppShell>
   );
 }
-
-interface MobileContextBarProps {
-  chapterNo: number;
-  onOpenChapters: () => void;
-  onOpenAssistant: () => void;
-  chapterTriggerRef: RefObject<HTMLButtonElement | null>;
-  assistantTriggerRef: RefObject<HTMLButtonElement | null>;
-}
-
-function MobileContextBar({
-  chapterNo,
-  onOpenChapters,
-  onOpenAssistant,
-  chapterTriggerRef,
-  assistantTriggerRef,
-}: MobileContextBarProps) {
-  return (
-    <div className="flex items-center justify-between gap-2 border-b border-line bg-panel px-4 py-2 xl:hidden">
-      <Button
-        ref={chapterTriggerRef}
-        onClick={onOpenChapters}
-        variant="secondary"
-        size="sm"
-      >
-        <PanelLeft className="h-4 w-4" aria-hidden="true" />
-        目录
-      </Button>
-      <span className="min-w-0 truncate font-mono text-xs text-ink-soft">
-        第 {chapterNo} 章
-      </span>
-      <Button
-        ref={assistantTriggerRef}
-        onClick={onOpenAssistant}
-        variant="secondary"
-        size="sm"
-      >
-        <PanelRight className="h-4 w-4" aria-hidden="true" />
-        助手
-      </Button>
-    </div>
-  );
-}
-
-interface DirectivePanelProps {
-  directive: string;
-  onDirectiveChange: (value: string) => void;
-  presetIds: readonly string[];
-  onTogglePreset: (id: string) => void;
-  // 空章默认展开（新手最需要看到输入框的时机）；满章默认收起以让出编辑视野。
-  defaultOpen: boolean;
-  // 发送键 = 写本章：把已选文风/剧情 + 自定义要求组装后逐字流式写进正文（不改成聊天气泡）。
-  streaming: boolean;
-  onWrite: () => void;
-  onStop: () => void;
-}
-
-// 本章写作指令面板（P0-2 提升）：正文正上方常驻的「和 AI 说话」输入条。
-// 标题「告诉 AI 这章想怎么写」+ HITL 微文案 +「?这是什么」常驻可见；空章默认展开露出输入框。
-// 发送键即「写本章」，沿用 composeDirective + 文风/剧情 chips + 流式打字机写进正文。
-function DirectivePanel({
-  directive,
-  onDirectiveChange,
-  presetIds,
-  onTogglePreset,
-  defaultOpen,
-  streaming,
-  onWrite,
-  onStop,
-}: DirectivePanelProps) {
-  const panelId = useId();
-  const [open, setOpen] = useState(defaultOpen);
-  const activeCount = presetIds.length + (directive.trim().length > 0 ? 1 : 0);
-  return (
-    <section className="border-b border-line bg-panel px-4 py-3 sm:px-6">
-      <div className="flex items-center justify-between gap-3">
-        <button
-          type="button"
-          onClick={() => setOpen((v) => !v)}
-          aria-expanded={open}
-          aria-controls={panelId}
-          className={`flex min-w-0 cursor-pointer items-center gap-2 rounded font-serif text-base text-ink hover:text-cinnabar ${focusRing}`}
-        >
-          <ChevronDown
-            className={`h-4 w-4 shrink-0 text-ink-soft transition-transform ${
-              open ? "rotate-180" : ""
-            }`}
-            aria-hidden="true"
-          />
-          <span className="truncate">告诉 AI 这章想怎么写</span>
-        </button>
-        <div className="flex shrink-0 items-center gap-2">
-          {activeCount > 0 ? (
-            <span className="rounded border border-line bg-bg px-2 py-0.5 text-xs text-ink-soft">
-              {activeCount} 项指令
-            </span>
-          ) : null}
-          {/* 常驻「发送键」= 写本章：始终可见（折叠时也在），逐字流式写进正文。带可见范围提示（P1-4）。 */}
-          {streaming ? (
-            <Button onClick={onStop} variant="danger" size="sm">
-              <Square className="h-4 w-4" aria-hidden="true" />
-              停
-            </Button>
-          ) : (
-            <Button onClick={onWrite} variant="primary" size="sm">
-              <PenLine className="h-4 w-4" aria-hidden="true" />
-              写本章
-              <span className="text-2xs font-normal text-panel/75">
-                整章·从头写
-              </span>
-            </Button>
-          )}
-          <HitlHelp />
-        </div>
-      </div>
-      <p className="mt-1 text-xs text-ink-soft">
-        AI 给草稿，你决定采不采用，原文永远你说了算。
-      </p>
-      {open ? (
-        <div id={panelId} className="mt-3 space-y-3">
-          <SectionHeader
-            title="你的写作要求"
-            description="选文风、点剧情需求、写自己的要求，只影响本次生成。"
-          />
-          <PresetGroup
-            label="文风"
-            presets={STYLE_PRESETS}
-            presetIds={presetIds}
-            onToggle={onTogglePreset}
-          />
-          <PresetGroup
-            label="剧情需求"
-            presets={PLOT_PRESETS}
-            presetIds={presetIds}
-            onToggle={onTogglePreset}
-          />
-          <label className="block">
-            <span className="mb-1 block text-sm text-ink-soft">自己的要求</span>
-            <TextArea
-              value={directive}
-              onChange={(e) => onDirectiveChange(e.target.value)}
-              rows={2}
-              placeholder="写点要求，AI 更懂你（留空则按大纲写）"
-            />
-          </label>
-          {activeCount > 0 ? (
-            <StatusNote variant="info">
-              写本章时会把已选文风/剧情预设和你的要求合并进本次生成请求。
-            </StatusNote>
-          ) : null}
-        </div>
-      ) : null}
-    </section>
-  );
-}
-
-interface AiVerbsRowProps {
-  streaming: boolean;
-  onContinue: () => void;
-  onRefineSelection: () => void;
-  onRewrite: () => void;
-  onToolbox: () => void;
-}
-
-// 「或让 AI:」次级动作行（P1-1）：常驻贴在中央输入条下方，把续写/润色/整章重写/工具箱
-// 归为「同一个 AI 的其它用法」（act-on-chapter 与导航分家）。每个动词带可见范围提示（P1-4）。
-// 生成中禁用（避免与流式写章并发），触发逻辑沿用 Workbench 既有 open* 回调（仅搬家、不改行为）。
-function AiVerbsRow({
-  streaming,
-  onContinue,
-  onRefineSelection,
-  onRewrite,
-  onToolbox,
-}: AiVerbsRowProps) {
-  return (
-    <div className="flex flex-wrap items-center gap-x-3 gap-y-2 border-b border-line bg-panel px-4 py-2 sm:px-6">
-      <span className="text-xs text-ink-soft">或让 AI：</span>
-      <VerbButton
-        icon={WrapText}
-        label="续写"
-        hint="接着往下写"
-        disabled={streaming}
-        onClick={onContinue}
-      />
-      <VerbButton
-        icon={Wand2}
-        label="润色选段"
-        hint="选中段·打磨"
-        disabled={streaming}
-        onClick={onRefineSelection}
-      />
-      <VerbButton
-        icon={RefreshCw}
-        label="整章重写"
-        hint="整章·基于现有重写"
-        disabled={streaming}
-        onClick={onRewrite}
-      />
-      <VerbButton
-        icon={Sparkles}
-        label="工具箱"
-        disabled={streaming}
-        onClick={onToolbox}
-      />
-    </div>
-  );
-}
-
-interface VerbButtonProps {
-  icon: typeof WrapText;
-  label: string;
-  // 可见（非 hover-only）范围提示：让作者点前就能预判对草稿的影响（P1-4）。工具箱无范围提示。
-  hint?: string;
-  disabled: boolean;
-  onClick: () => void;
-}
-
-function VerbButton({ icon: Icon, label, hint, disabled, onClick }: VerbButtonProps) {
-  return (
-    <Button onClick={onClick} disabled={disabled} variant="secondary" size="sm">
-      <Icon className="h-4 w-4" aria-hidden="true" />
-      {label}
-      {hint ? <span className="text-2xs text-ink-soft">{hint}</span> : null}
-    </Button>
-  );
-}
-
-// 「?这是什么」：常驻、可再发现的说明（非一次性 coach）——解释「和 AI 说话」的闭环。
-// 仿 AiToolbarMoreMenu：按钮 + 轻量弹层，Esc / 点击外部关闭，还原焦点。
-function HitlHelp() {
-  const [open, setOpen] = useState(false);
-  const popId = useId();
-  const rootRef = useRef<HTMLDivElement>(null);
-  const buttonRef = useRef<HTMLButtonElement>(null);
-
-  useEffect(() => {
-    if (!open) return;
-    const onKeyDown = (e: KeyboardEvent): void => {
-      if (e.key === "Escape") {
-        setOpen(false);
-        buttonRef.current?.focus();
-      }
-    };
-    const onPointerDown = (e: PointerEvent): void => {
-      const target = e.target;
-      if (target instanceof Node && !rootRef.current?.contains(target)) {
-        setOpen(false);
-      }
-    };
-    window.addEventListener("keydown", onKeyDown);
-    window.addEventListener("pointerdown", onPointerDown);
-    return () => {
-      window.removeEventListener("keydown", onKeyDown);
-      window.removeEventListener("pointerdown", onPointerDown);
-    };
-  }, [open]);
-
-  return (
-    <div ref={rootRef} className="relative">
-      <button
-        ref={buttonRef}
-        type="button"
-        aria-haspopup="dialog"
-        aria-expanded={open}
-        aria-controls={popId}
-        onClick={() => setOpen((v) => !v)}
-        className={buttonClass({
-          variant: "ghost",
-          size: "sm",
-          className: "gap-1 text-xs text-ink-soft",
-        })}
-      >
-        <HelpCircle className="h-4 w-4" aria-hidden="true" />
-        这是什么
-      </button>
-      {open ? (
-        <div
-          id={popId}
-          role="dialog"
-          aria-label="怎么和 AI 说话"
-          className="absolute right-0 z-30 mt-2 w-72 max-w-[80vw] rounded border border-line bg-panel p-3 text-sm text-ink-soft shadow-paper"
-        >
-          <p className="mb-1 font-serif text-sm text-ink">怎么和 AI 说话</p>
-          <p>
-            在这条写下要求，点「写本章」——AI 会把草稿逐字写进正文。草稿随时能改；
-            满意了去「审稿」验收。原文永远你说了算。
-          </p>
-        </div>
-      ) : null}
-    </div>
-  );
-}
-
-interface PresetGroupProps {
-  label: string;
-  presets: readonly Preset[];
-  presetIds: readonly string[];
-  onToggle: (id: string) => void;
-}
-
-// 一组预设 chips（文风 / 剧情需求）：点选 toggle，选中高亮。id 统一进 presetIds。
-function PresetGroup({ label, presets, presetIds, onToggle }: PresetGroupProps) {
-  return (
-    <div>
-      <p className="mb-1 text-sm text-ink-soft">{label}</p>
-      <div className="flex flex-wrap gap-2" role="group" aria-label={label}>
-        {presets.map((preset) => {
-          const active = presetIds.includes(preset.id);
-          return (
-            <Button
-              key={preset.id}
-              type="button"
-              aria-pressed={active}
-              onClick={() => onToggle(preset.id)}
-              variant={active ? "outline" : "secondary"}
-              size="sm"
-            >
-              {preset.label}
-            </Button>
-          );
-        })}
-      </div>
-    </div>
-  );
-}
-
-// 写章失败提示：友好文案（不暴露 raw code）+ 可选「去设置」动作（F4）。
-function StreamErrorNote({
-  streamError,
-}: {
-  streamError: { code: string; message: string };
-}) {
-  const friendly = friendlyError(streamError.code, streamError.message);
-  return (
-    <p className="mb-2 text-sm text-conflict">
-      {friendly.text}
-      {friendly.actionHref ? (
-        <>
-          {" "}
-          <Link
-            href={friendly.actionHref}
-            className="underline hover:text-cinnabar"
-          >
-            {friendly.actionLabel}
-          </Link>
-        </>
-      ) : null}
-    </p>
-  );
-}
-
-// 底栏瘦身（P1-1）：act-on-chapter 动词与纯导航都已上移/移除，底栏只余
-// 状态（字数/保存/播报）+ 流式时的「停」+ 唯一强调的「审稿」前进 CTA + 速查/对话记录抽屉入口。
-interface ToolbarProps {
-  projectId: string;
-  chapterNo: number;
-  wordCount: number;
-  savedLabel: string | null;
-  saveStatus: ReturnType<typeof useAutosave>["status"];
-  streaming: boolean;
-  streamError: { code: string; message: string } | null;
-  // 流式里程碑播报句（完成/停止/失败）；仅在 role=status 区出现，不逐 token 刷新。
-  liveMessage: string;
-  // 流式时的「停」：底栏 sticky，滚到长正文下方也够得着（中央条会滚出视野）。
-  onStop: () => void;
-  // 打开上下文速查抽屉（WFW-6）。
-  onOpenContext: () => void;
-  contextTriggerRef: RefObject<HTMLButtonElement | null>;
-  // 打开对话记录抽屉（AC-3）。
-  onOpenConversation: () => void;
-  conversationTriggerRef: RefObject<HTMLButtonElement | null>;
-}
-
-function Toolbar({
-  projectId,
-  chapterNo,
-  wordCount,
-  savedLabel,
-  saveStatus,
-  streaming,
-  streamError,
-  liveMessage,
-  onStop,
-  onOpenContext,
-  contextTriggerRef,
-  onOpenConversation,
-  conversationTriggerRef,
-}: ToolbarProps) {
-  return (
-    <div className="sticky bottom-0 z-10 border-t border-line bg-panel/95 px-4 py-2 backdrop-blur sm:px-6 sm:py-3">
-      {streamError ? <StreamErrorNote streamError={streamError} /> : null}
-      <div className="grid gap-2 sm:flex sm:flex-wrap sm:items-center sm:gap-3">
-        <div className="flex min-w-0 flex-wrap items-center gap-2">
-        {streaming ? (
-          <Button onClick={onStop} variant="danger" size="sm">
-            <Square className="h-4 w-4" aria-hidden="true" />
-            停
-          </Button>
-        ) : null}
-        {streaming ? (
-          // ThinkingIndicator 自带 role=status，开始时播报一次「生成中」；
-          // 易变字数 aria-hidden，仅供视觉，不逐 token 打扰屏读。
-          <span className="inline-flex items-center gap-2">
-            <ThinkingIndicator label="生成中" className="text-xs text-cinnabar" />
-            <span
-              aria-hidden="true"
-              className="font-mono text-xs text-cinnabar"
-            >
-              {wordCount} 字
-            </span>
-          </span>
-        ) : (
-          <span className="font-mono text-xs text-ink-soft">
-            字数 {wordCount}
-          </span>
-        )}
-        {/* 终结句播报区：完成/停止/失败时写入，屏读只播报里程碑。 */}
-        <span className="sr-only" role="status" aria-live="polite">
-          {liveMessage}
-        </span>
-        {CONTEXT_DRAWER_ENABLED ? (
-          <Button
-            ref={contextTriggerRef}
-            onClick={onOpenContext}
-            variant="secondary"
-            size="sm"
-            title="打开上下文速查（设定库/大纲/伏笔/规则/文风）"
-          >
-            <BookMarked className="h-4 w-4" aria-hidden="true" />
-            速查
-          </Button>
-        ) : null}
-        {AI_CONVERSATION_ENABLED ? (
-          <Button
-            ref={conversationTriggerRef}
-            onClick={onOpenConversation}
-            variant="secondary"
-            size="sm"
-            title="打开对话记录（润色/重写/续写/工具箱往复留痕的只读日志）"
-          >
-            <MessagesSquare className="h-4 w-4" aria-hidden="true" />
-            对话记录
-          </Button>
-        ) : null}
-        {/* 唯一强调的「审稿」= 写→审→验收的前进 CTA（导航去重后仅此一处强调，左栏另有入口）。 */}
-        <Link
-          href={`/projects/${projectId}/review?chapter=${chapterNo}`}
-          className={buttonClass({ variant: "outline", size: "sm" })}
-        >
-          <ClipboardCheck className="h-4 w-4" aria-hidden="true" />
-          审稿
-        </Link>
-        </div>
-        <span
-          role="status"
-          aria-live="polite"
-          className="min-w-0 font-mono text-xs text-ink-soft sm:ml-auto"
-        >
-          <FileText className="mr-1 inline h-3.5 w-3.5" aria-hidden="true" />
-          {saveStatus === "saving"
-            ? "保存中…"
-            : saveStatus === "error"
-              ? "保存失败"
-              : (savedLabel ?? "尚未保存")}
-        </span>
-      </div>
-    </div>
-  );
-}
diff --git a/apps/web/components/workbench/WorkbenchToolbar.tsx b/apps/web/components/workbench/WorkbenchToolbar.tsx
new file mode 100644
index 0000000..2d146e6
--- /dev/null
+++ b/apps/web/components/workbench/WorkbenchToolbar.tsx
@@ -0,0 +1,209 @@
+"use client";
+
+import Link from "next/link";
+import type { RefObject } from "react";
+import {
+  BookMarked,
+  ClipboardCheck,
+  FileText,
+  Maximize2,
+  MessagesSquare,
+  Minimize2,
+  Square,
+} from "lucide-react";
+
+import { ThinkingIndicator } from "@/components/ThinkingIndicator";
+import { Button } from "@/components/ui/Button";
+import type { useAutosave } from "@/lib/autosave/useAutosave";
+import { friendlyError } from "@/lib/errors/messages";
+import { buttonClass } from "@/lib/ui/variants";
+import { CONTEXT_DRAWER_ENABLED } from "./ContextDrawer";
+import { AI_CONVERSATION_ENABLED } from "./AiConversationDrawer";
+
+// 写章失败提示：友好文案（不暴露 raw code）+ 可选「去设置」动作（F4）。
+function StreamErrorNote({
+  streamError,
+}: {
+  streamError: { code: string; message: string };
+}) {
+  const friendly = friendlyError(streamError.code, streamError.message);
+  return (
+    <p className="mb-2 text-sm text-conflict">
+      {friendly.text}
+      {friendly.actionHref ? (
+        <>
+          {" "}
+          <Link
+            href={friendly.actionHref}
+            className="underline hover:text-cinnabar"
+          >
+            {friendly.actionLabel}
+          </Link>
+        </>
+      ) : null}
+    </p>
+  );
+}
+
+// 专注写作开关（P3-4）：图标按钮，进入=隐藏左侧图标导航 + 目录 TOC 加宽正文，退出还原。
+// aria-pressed 表状态、aria-label 表动作，键盘可达（复用共享 Button 焦点环）。
+function FocusToggle({
+  focus,
+  onToggle,
+}: {
+  focus: boolean;
+  onToggle: () => void;
+}) {
+  return (
+    <Button
+      onClick={onToggle}
+      variant="secondary"
+      size="sm"
+      aria-pressed={focus}
+      aria-label={focus ? "退出专注写作模式" : "进入专注写作模式（隐藏侧栏，加宽正文）"}
+      title={focus ? "退出专注写作" : "专注写作"}
+    >
+      {focus ? (
+        <Minimize2 className="h-4 w-4" aria-hidden="true" />
+      ) : (
+        <Maximize2 className="h-4 w-4" aria-hidden="true" />
+      )}
+      专注
+    </Button>
+  );
+}
+
+// 底栏（P1-1 瘦身 + P3-6 分区）：按「信息 | 操作 | 状态」三区排布。
+// 信息=字数/生成中；操作=速查/对话记录/审稿/专注（+流式时的「停」）；状态=保存态（右侧）。
+interface ToolbarProps {
+  projectId: string;
+  chapterNo: number;
+  wordCount: number;
+  savedLabel: string | null;
+  saveStatus: ReturnType<typeof useAutosave>["status"];
+  streaming: boolean;
+  streamError: { code: string; message: string } | null;
+  // 流式里程碑播报句（完成/停止/失败）；仅在 role=status 区出现，不逐 token 刷新。
+  liveMessage: string;
+  // 流式时的「停」：底栏 sticky，滚到长正文下方也够得着（中央条会滚出视野）。
+  onStop: () => void;
+  // 专注写作开关（P3-4）。
+  focus: boolean;
+  onToggleFocus: () => void;
+  // 打开上下文速查抽屉（WFW-6）。
+  onOpenContext: () => void;
+  contextTriggerRef: RefObject<HTMLButtonElement | null>;
+  // 打开对话记录抽屉（AC-3）。
+  onOpenConversation: () => void;
+  conversationTriggerRef: RefObject<HTMLButtonElement | null>;
+}
+
+export function Toolbar({
+  projectId,
+  chapterNo,
+  wordCount,
+  savedLabel,
+  saveStatus,
+  streaming,
+  streamError,
+  liveMessage,
+  onStop,
+  focus,
+  onToggleFocus,
+  onOpenContext,
+  contextTriggerRef,
+  onOpenConversation,
+  conversationTriggerRef,
+}: ToolbarProps) {
+  return (
+    <div className="sticky bottom-0 z-10 border-t border-line bg-panel/95 px-4 py-2 backdrop-blur sm:px-6 sm:py-3">
+      {streamError ? <StreamErrorNote streamError={streamError} /> : null}
+      <div className="grid gap-2 sm:flex sm:flex-wrap sm:items-center sm:gap-3">
+        {/* 信息区：字数 / 生成中（含流式时的「停」）。 */}
+        <div className="flex min-w-0 flex-wrap items-center gap-2">
+          {streaming ? (
+            <Button onClick={onStop} variant="danger" size="sm">
+              <Square className="h-4 w-4" aria-hidden="true" />
+              停
+            </Button>
+          ) : null}
+          {streaming ? (
+            // ThinkingIndicator 自带 role=status，开始时播报一次「生成中」；
+            // 易变字数 aria-hidden，仅供视觉，不逐 token 打扰屏读。
+            <span className="inline-flex items-center gap-2">
+              <ThinkingIndicator
+                label="生成中"
+                className="text-xs text-cinnabar"
+              />
+              <span
+                aria-hidden="true"
+                className="font-mono text-xs text-cinnabar"
+              >
+                {wordCount} 字
+              </span>
+            </span>
+          ) : (
+            <span className="font-mono text-xs text-ink-soft">
+              字数 {wordCount}
+            </span>
+          )}
+          {/* 终结句播报区：完成/停止/失败时写入，屏读只播报里程碑。 */}
+          <span className="sr-only" role="status" aria-live="polite">
+            {liveMessage}
+          </span>
+        </div>
+
+        {/* 操作区：速查 / 对话记录 / 审稿 / 专注；与信息区以细分隔线拉开。 */}
+        <div className="flex min-w-0 flex-wrap items-center gap-2 sm:border-l sm:border-line-soft sm:pl-3">
+          {CONTEXT_DRAWER_ENABLED ? (
+            <Button
+              ref={contextTriggerRef}
+              onClick={onOpenContext}
+              variant="secondary"
+              size="sm"
+              title="打开上下文速查（设定库/大纲/伏笔/规则/文风）"
+            >
+              <BookMarked className="h-4 w-4" aria-hidden="true" />
+              速查
+            </Button>
+          ) : null}
+          {AI_CONVERSATION_ENABLED ? (
+            <Button
+              ref={conversationTriggerRef}
+              onClick={onOpenConversation}
+              variant="secondary"
+              size="sm"
+              title="打开对话记录（润色/重写/续写/工具箱往复留痕的只读日志）"
+            >
+              <MessagesSquare className="h-4 w-4" aria-hidden="true" />
+              对话记录
+            </Button>
+          ) : null}
+          <FocusToggle focus={focus} onToggle={onToggleFocus} />
+          {/* 唯一强调的「审稿」= 写→审→验收的前进 CTA（导航去重后仅此一处强调，左栏另有入口）。 */}
+          <Link
+            href={`/projects/${projectId}/review?chapter=${chapterNo}`}
+            className={buttonClass({ variant: "outline", size: "sm" })}
+          >
+            <ClipboardCheck className="h-4 w-4" aria-hidden="true" />
+            审稿
+          </Link>
+        </div>
+
+        {/* 状态区：保存态，右侧对齐。 */}
+        <span
+          role="status"
+          aria-live="polite"
+          className="min-w-0 font-mono text-xs text-ink-soft sm:ml-auto"
+        >
+          <FileText className="mr-1 inline h-3.5 w-3.5" aria-hidden="true" />
+          {saveStatus === "saving"
+            ? "保存中…"
+            : saveStatus === "error"
+              ? "保存失败"
+              : (savedLabel ?? "尚未保存")}
+        </span>
+      </div>
+    </div>
+  );
+}
diff --git a/apps/web/lib/workbench/useFocusMode.test.ts b/apps/web/lib/workbench/useFocusMode.test.ts
new file mode 100644
index 0000000..0cbf9e7
--- /dev/null
+++ b/apps/web/lib/workbench/useFocusMode.test.ts
@@ -0,0 +1,61 @@
+// @vitest-environment jsdom
+import { act, renderHook } from "@testing-library/react";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+
+import { FOCUS_MODE_KEY, useFocusMode } from "./useFocusMode";
+
+// 本仓库 jsdom 未提供可用的 Storage（setItem/clear 缺失），装一个内存版 localStorage。
+function installMemoryStorage(): Storage {
+  const map = new Map<string, string>();
+  const storage: Storage = {
+    get length() {
+      return map.size;
+    },
+    clear: () => map.clear(),
+    getItem: (key) => (map.has(key) ? (map.get(key) ?? null) : null),
+    key: (index) => Array.from(map.keys())[index] ?? null,
+    removeItem: (key) => map.delete(key),
+    setItem: (key, value) => map.set(key, String(value)),
+  };
+  Object.defineProperty(window, "localStorage", {
+    value: storage,
+    configurable: true,
+  });
+  return storage;
+}
+
+describe("useFocusMode", () => {
+  beforeEach(() => {
+    installMemoryStorage();
+  });
+  afterEach(() => {
+    window.localStorage.clear();
+  });
+
+  it("默认关闭（无存档时 focus=false）", () => {
+    const { result } = renderHook(() => useFocusMode());
+    expect(result.current.focus).toBe(false);
+  });
+
+  it("toggle 翻转并把状态写入 localStorage", () => {
+    const { result } = renderHook(() => useFocusMode());
+
+    act(() => result.current.toggle());
+
+    expect(result.current.focus).toBe(true);
+    expect(window.localStorage.getItem(FOCUS_MODE_KEY)).toBe("1");
+
+    act(() => result.current.toggle());
+
+    expect(result.current.focus).toBe(false);
+    expect(window.localStorage.getItem(FOCUS_MODE_KEY)).toBe("0");
+  });
+
+  it("挂载时从 localStorage 恢复已开启状态", () => {
+    window.localStorage.setItem(FOCUS_MODE_KEY, "1");
+
+    const { result } = renderHook(() => useFocusMode());
+
+    expect(result.current.focus).toBe(true);
+  });
+});
diff --git a/apps/web/lib/workbench/useFocusMode.ts b/apps/web/lib/workbench/useFocusMode.ts
new file mode 100644
index 0000000..fceda87
--- /dev/null
+++ b/apps/web/lib/workbench/useFocusMode.ts
@@ -0,0 +1,46 @@
+"use client";
+
+import { useCallback, useEffect, useState } from "react";
+
+// 「专注写作」偏好的持久化键（对齐既有 `ww.` 前缀约定）。
+export const FOCUS_MODE_KEY = "ww.workbench_focus_mode";
+
+export interface FocusMode {
+  // true=专注模式：隐藏左侧图标导航 + 目录 TOC，让宽给正文；false=常规四栏。
+  focus: boolean;
+  toggle: () => void;
+}
+
+function persist(focus: boolean): void {
+  if (typeof window === "undefined") return;
+  try {
+    window.localStorage.setItem(FOCUS_MODE_KEY, focus ? "1" : "0");
+  } catch {
+    // 隐私模式/配额异常忽略：专注模式是纯 UI 偏好，写盘失败不影响写作功能。
+  }
+}
+
+// 记住「专注写作」开关（P3-4）：SSR 首帧恒关（避免 hydration 不一致），
+// 挂载后再从 localStorage 恢复；toggle 即时写回。仅桌面（≥xl）改变栅格，窄屏本就单列不受影响。
+export function useFocusMode(): FocusMode {
+  const [focus, setFocus] = useState(false);
+
+  useEffect(() => {
+    if (typeof window === "undefined") return;
+    try {
+      setFocus(window.localStorage.getItem(FOCUS_MODE_KEY) === "1");
+    } catch {
+      // 读盘失败则维持默认关闭。
+    }
+  }, []);
+
+  const toggle = useCallback(() => {
+    setFocus((prev) => {
+      const next = !prev;
+      persist(next);
+      return next;
+    });
+  }, []);
+
+  return { focus, toggle };
+}