diff --git a/web/src/app/AppLayout.tsx b/web/src/app/AppLayout.tsx
index 76f8aad..e018204 100644
--- a/web/src/app/AppLayout.tsx
+++ b/web/src/app/AppLayout.tsx
@@ -4,6 +4,7 @@ import { useState } from 'react'
 import { NavLink, Outlet } from 'react-router-dom'
 
 import { Button } from '../components/ui/button'
+import { SessionList } from '../features/chat/SessionList'
 import { cn } from '../lib/utils'
 
 function Navigation({ onNavigate }: { onNavigate?: () => void }) {
@@ -22,6 +23,7 @@ function Navigation({ onNavigate }: { onNavigate?: () => void }) {
           <BookOpenText size={17} /><span>文档资料库</span>
         </NavLink>
       </nav>
+      <SessionList onNavigate={onNavigate} />
       <div className="sidebar-note">
         <span className="status-dot" />
         <div><strong>严格知识库模式</strong><small>回答必须引用已索引资料</small></div>
diff --git a/web/src/app/router.tsx b/web/src/app/router.tsx
index 6e71c75..44ac9fd 100644
--- a/web/src/app/router.tsx
+++ b/web/src/app/router.tsx
@@ -1,7 +1,7 @@
 import { Navigate, createBrowserRouter } from 'react-router-dom'
 
 import { AppLayout } from './AppLayout'
-import { PlaceholderPage } from './PlaceholderPage'
+import { ChatPage } from '../features/chat/ChatPage'
 import { DocumentsPage } from '../features/documents/DocumentsPage'
 
 export const router = createBrowserRouter([
@@ -10,8 +10,8 @@ export const router = createBrowserRouter([
     element: <AppLayout />,
     children: [
       { index: true, element: <Navigate to="/chat" replace /> },
-      { path: 'chat', element: <PlaceholderPage /> },
-      { path: 'chat/:sessionId', element: <PlaceholderPage /> },
+      { path: 'chat', element: <ChatPage /> },
+      { path: 'chat/:sessionId', element: <ChatPage /> },
       { path: 'documents', element: <DocumentsPage /> },
       { path: 'documents/:documentId', element: <DocumentsPage /> },
     ],
diff --git a/web/src/features/chat/ChatComposer.tsx b/web/src/features/chat/ChatComposer.tsx
new file mode 100644
index 0000000..ba9334c
--- /dev/null
+++ b/web/src/features/chat/ChatComposer.tsx
@@ -0,0 +1,22 @@
+import { SendHorizontal, Square } from 'lucide-react'
+import { useState } from 'react'
+
+import { Button } from '../../components/ui/button'
+
+type Props = { streaming: boolean; onSend: (query: string) => void; onCancel: () => void }
+
+export function ChatComposer({ streaming, onSend, onCancel }: Props) {
+  const [query, setQuery] = useState('')
+  function submit() {
+    const value = query.trim()
+    if (!value || streaming) return
+    setQuery(''); onSend(value)
+  }
+  return (
+    <div className="chat-composer">
+      <textarea value={query} onChange={(event) => setQuery(event.target.value)} onKeyDown={(event) => { if (event.key === 'Enter' && !event.shiftKey) { event.preventDefault(); submit() } }} placeholder="向知识库提问…" rows={2} disabled={streaming} />
+      {streaming ? <Button variant="secondary" size="icon" onClick={onCancel} aria-label="停止生成"><Square size={15} fill="currentColor" /></Button> : <Button size="icon" onClick={submit} disabled={!query.trim()} aria-label="发送问题"><SendHorizontal size={17} /></Button>}
+      <small>Enter 发送 · Shift + Enter 换行</small>
+    </div>
+  )
+}
diff --git a/web/src/features/chat/ChatPage.tsx b/web/src/features/chat/ChatPage.tsx
new file mode 100644
index 0000000..05e6647
--- /dev/null
+++ b/web/src/features/chat/ChatPage.tsx
@@ -0,0 +1,61 @@
+import * as Dialog from '@radix-ui/react-dialog'
+import { PanelRightOpen, Radar, Sparkles } from 'lucide-react'
+import { useCallback, useEffect, useState } from 'react'
+import { useNavigate, useParams } from 'react-router-dom'
+
+import { Button } from '../../components/ui/button'
+import type { Message, Source } from '../../lib/types'
+import { announceSessionChange, createSession, listMessages } from './api'
+import { ChatComposer } from './ChatComposer'
+import { EvidencePanel } from './EvidencePanel'
+import { MessageList } from './MessageList'
+import { useChatStreamStore } from './store'
+import { useChatStream } from './useChatStream'
+
+export function ChatPage() {
+  const { sessionId } = useParams()
+  const navigate = useNavigate()
+  const [messages, setMessages] = useState<Message[]>([])
+  const [evidenceOpen, setEvidenceOpen] = useState(false)
+  const stream = useChatStreamStore()
+
+  const refreshMessages = useCallback(async () => {
+    if (!sessionId) { setMessages([]); return }
+    const page = await listMessages(sessionId)
+    setMessages(page.items); announceSessionChange()
+  }, [sessionId])
+
+  useEffect(() => {
+    if (!sessionId) return
+    void listMessages(sessionId).then((page) => setMessages(page.items))
+  }, [sessionId])
+
+  const { send, cancel } = useChatStream(async () => { await refreshMessages(); useChatStreamStore.getState().reset() })
+
+  async function handleSend(query: string) {
+    let target = sessionId
+    if (!target) {
+      const session = await createSession(); target = session.id; navigate(`/chat/${target}`); announceSessionChange()
+    }
+    await send(target, query)
+  }
+
+  function chooseSource(source: Source, sources: Source[] = stream.sources) {
+    stream.setSources(sources)
+    stream.selectSource(source)
+    setEvidenceOpen(true)
+  }
+  const streaming = stream.phase === 'researching' || stream.phase === 'answering'
+
+  return (
+    <section className="chat-workspace">
+      <main className="chat-main">
+        <header className="chat-header"><div><p className="eyebrow">KNOWLEDGE CONVERSATION</p><h1>{sessionId ? '知识库对话' : '开始新研究'}</h1></div><Button className="evidence-trigger" variant="secondary" size="sm" onClick={() => setEvidenceOpen(true)}><PanelRightOpen size={15} />本轮证据</Button></header>
+        <div className="conversation-scroll"><MessageList messages={messages} onSource={chooseSource} />{stream.activeQuery && <div className="streaming-turn"><article className="message message--user"><div className="message-body"><p>{stream.activeQuery}</p></div></article><article className="message message--assistant"><div className="message-avatar"><Sparkles size={15} /></div><div className="message-body">{stream.phase === 'researching' && <p className="research-state"><Radar className="pulse" size={16} />研究 Agent 正在检索知识库…</p>}{stream.text && <p className="answer-copy">{stream.text}<span className="typing-cursor" /></p>}{stream.error && <p className="failed-message">{stream.error}</p>}</div></article></div>}</div>
+        <ChatComposer streaming={streaming} onSend={(query) => void handleSend(query)} onCancel={cancel} />
+      </main>
+      <div className="evidence-desktop"><EvidencePanel sources={stream.sources} selected={stream.selectedSource} onSelect={stream.selectSource} /></div>
+      <Dialog.Root open={evidenceOpen} onOpenChange={setEvidenceOpen}><Dialog.Portal><Dialog.Overlay className="dialog-overlay" /><Dialog.Content className="evidence-drawer"><Dialog.Title className="sr-only">本轮证据</Dialog.Title><EvidencePanel sources={stream.sources} selected={stream.selectedSource} onSelect={stream.selectSource} onClose={() => setEvidenceOpen(false)} /></Dialog.Content></Dialog.Portal></Dialog.Root>
+    </section>
+  )
+}
diff --git a/web/src/features/chat/EvidencePanel.tsx b/web/src/features/chat/EvidencePanel.tsx
new file mode 100644
index 0000000..54581db
--- /dev/null
+++ b/web/src/features/chat/EvidencePanel.tsx
@@ -0,0 +1,16 @@
+import { BookOpenCheck, FileText, X } from 'lucide-react'
+
+import { Button } from '../../components/ui/button'
+import type { Source } from '../../lib/types'
+import { cn } from '../../lib/utils'
+
+type Props = { sources: Source[]; selected: Source | null; onSelect: (source: Source) => void; onClose?: () => void }
+
+export function EvidencePanel({ sources, selected, onSelect, onClose }: Props) {
+  return (
+    <aside className="evidence-panel">
+      <header className="evidence-header"><div><p className="eyebrow">EVIDENCE</p><h2>本轮证据</h2></div><span>{sources.length} 条来源</span>{onClose && <Button variant="ghost" size="icon" onClick={onClose}><X size={17} /></Button>}</header>
+      {sources.length === 0 ? <div className="evidence-empty"><BookOpenCheck size={23} /><strong>等待研究结果</strong><span>检索到的原文片段会在这里出现。</span></div> : <><div className="source-list">{sources.map((source) => <button key={source.chunk_id} className={cn('source-card', selected?.chunk_id === source.chunk_id && 'source-card--active')} onClick={() => onSelect(source)}><FileText size={14} /><span><strong>{source.label} · {source.filename}</strong><small>第 {source.order_index + 1} 段 · {(source.score * 100).toFixed(0)}%</small></span></button>)}</div>{selected && <article className="source-detail"><header><strong>{selected.label} · 来源详情</strong><span>{selected.page_number ? `第 ${selected.page_number} 页` : `第 ${selected.order_index + 1} 段`}</span></header><p>{selected.content}</p></article>}</>}
+    </aside>
+  )
+}
diff --git a/web/src/features/chat/MessageList.tsx b/web/src/features/chat/MessageList.tsx
new file mode 100644
index 0000000..7349617
--- /dev/null
+++ b/web/src/features/chat/MessageList.tsx
@@ -0,0 +1,28 @@
+import { Bot, CircleAlert, UserRound } from 'lucide-react'
+
+import type { Message, Source } from '../../lib/types'
+
+function AnswerContent({ content, sources, onSource }: { content: string; sources: Source[]; onSource: (source: Source, sources: Source[]) => void }) {
+  const lookup = new Map(sources.map((source) => [source.label, source]))
+  return <p className="answer-copy">{content.split(/(\[S\d+])/g).map((part, index) => {
+    const label = part.match(/^\[(S\d+)]$/)?.[1]
+    const source = label ? lookup.get(label) : undefined
+    if (!label) return <span key={index}>{part}</span>
+    if (!source) return <span key={index} className="citation citation--deleted">来源已删除</span>
+    return <button key={index} className="citation" onClick={() => onSource(source, sources)}>{label}</button>
+  })}</p>
+}
+
+type Props = { messages: Message[]; onSource: (source: Source, sources: Source[]) => void }
+
+export function MessageList({ messages, onSource }: Props) {
+  if (messages.length === 0) return <div className="chat-empty"><div><Bot size={28} /></div><p className="eyebrow">STRICT KNOWLEDGE MODE</p><h2>从有出处的答案开始</h2><span>系统会先让研究 Agent 检索资料，再由主 Agent 组织回答。</span></div>
+  return (
+    <div className="message-list">
+      {messages.map((message) => <article key={message.id} className={`message message--${message.role}`}>
+        <div className="message-avatar">{message.role === 'user' ? <UserRound size={15} /> : <Bot size={15} />}</div>
+        <div className="message-body"><header><strong>{message.role === 'user' ? '你' : '知识库助手'}</strong><time>{new Date(message.created_at).toLocaleTimeString('zh-CN', { hour: '2-digit', minute: '2-digit' })}</time></header>{message.status === 'failed' ? <p className="failed-message"><CircleAlert size={14} />回答生成失败，可重新发送问题。</p> : message.role === 'assistant' ? <AnswerContent content={message.content} sources={message.sources} onSource={onSource} /> : <p>{message.content}</p>}</div>
+      </article>)}
+    </div>
+  )
+}
diff --git a/web/src/features/chat/SessionList.tsx b/web/src/features/chat/SessionList.tsx
new file mode 100644
index 0000000..6695d74
--- /dev/null
+++ b/web/src/features/chat/SessionList.tsx
@@ -0,0 +1,52 @@
+import { MessageSquarePlus, Trash2 } from 'lucide-react'
+import { useCallback, useEffect, useState } from 'react'
+import { useLocation, useNavigate, useParams } from 'react-router-dom'
+
+import { Button } from '../../components/ui/button'
+import type { Session } from '../../lib/types'
+import { cn } from '../../lib/utils'
+import { createSession, deleteSession, listSessions } from './api'
+
+export function SessionList({ onNavigate }: { onNavigate?: () => void }) {
+  const [sessions, setSessions] = useState<Session[]>([])
+  const navigate = useNavigate()
+  const { sessionId } = useParams()
+  const isChat = useLocation().pathname.startsWith('/chat')
+
+  const refresh = useCallback(async () => {
+    if (!isChat) return
+    const page = await listSessions()
+    setSessions(page.items)
+  }, [isChat])
+
+  useEffect(() => {
+    if (!isChat) return
+    void listSessions().then((page) => setSessions(page.items))
+    const listener = () => void refresh()
+    window.addEventListener('kbqa:sessions-changed', listener)
+    return () => window.removeEventListener('kbqa:sessions-changed', listener)
+  }, [isChat, refresh])
+
+  if (!isChat) return null
+
+  async function addSession() {
+    const session = await createSession()
+    await refresh(); navigate(`/chat/${session.id}`); onNavigate?.()
+  }
+  async function removeSession(id: string) {
+    if (!window.confirm('确定删除这个会话及全部历史吗？')) return
+    await deleteSession(id); await refresh()
+    if (sessionId === id) navigate('/chat')
+  }
+
+  return (
+    <section className="session-rail">
+      <Button className="new-session" size="sm" onClick={() => void addSession()}><MessageSquarePlus size={15} />新建会话</Button>
+      <p className="nav-label">最近会话</p>
+      <div className="session-list">
+        {sessions.map((session) => <div key={session.id} className={cn('session-item', session.id === sessionId && 'session-item--active')}><button onClick={() => { navigate(`/chat/${session.id}`); onNavigate?.() }}><strong>{session.title || '新会话'}</strong><span>{new Date(session.updated_at).toLocaleDateString('zh-CN')}</span></button><Button variant="ghost" size="icon" title="删除会话" onClick={() => void removeSession(session.id)}><Trash2 size={13} /></Button></div>)}
+        {sessions.length === 0 && <p className="session-empty">还没有历史会话</p>}
+      </div>
+    </section>
+  )
+}
diff --git a/web/src/features/chat/api.ts b/web/src/features/chat/api.ts
new file mode 100644
index 0000000..79d610b
--- /dev/null
+++ b/web/src/features/chat/api.ts
@@ -0,0 +1,25 @@
+import { apiRequest } from '../../lib/api'
+import type { Message, Page, Session } from '../../lib/types'
+
+export function createSession(title?: string) {
+  return apiRequest<Session>('/api/v1/sessions', {
+    method: 'POST',
+    body: JSON.stringify({ title: title || null }),
+  })
+}
+
+export function listSessions() {
+  return apiRequest<Page<Session>>('/api/v1/sessions?limit=100')
+}
+
+export function listMessages(sessionId: string) {
+  return apiRequest<Page<Message>>(`/api/v1/sessions/${sessionId}/messages?limit=100`)
+}
+
+export function deleteSession(sessionId: string) {
+  return apiRequest<void>(`/api/v1/sessions/${sessionId}`, { method: 'DELETE' })
+}
+
+export function announceSessionChange() {
+  window.dispatchEvent(new Event('kbqa:sessions-changed'))
+}
diff --git a/web/src/features/chat/store.ts b/web/src/features/chat/store.ts
new file mode 100644
index 0000000..a3ea855
--- /dev/null
+++ b/web/src/features/chat/store.ts
@@ -0,0 +1,41 @@
+import { create } from 'zustand'
+
+import type { Source } from '../../lib/types'
+
+type Phase = 'idle' | 'researching' | 'answering' | 'error'
+
+type ChatStreamState = {
+  phase: Phase
+  activeQuery: string
+  text: string
+  sources: Source[]
+  selectedSource: Source | null
+  error: string | null
+  start: (query: string) => void
+  setPhase: (phase: Phase) => void
+  appendText: (content: string) => void
+  setSources: (sources: Source[]) => void
+  selectSource: (source: Source | null) => void
+  fail: (message: string) => void
+  reset: () => void
+}
+
+const initial = {
+  phase: 'idle' as Phase,
+  activeQuery: '',
+  text: '',
+  sources: [] as Source[],
+  selectedSource: null as Source | null,
+  error: null as string | null,
+}
+
+export const useChatStreamStore = create<ChatStreamState>((set) => ({
+  ...initial,
+  start: (query) => set({ ...initial, phase: 'researching', activeQuery: query }),
+  setPhase: (phase) => set({ phase }),
+  appendText: (content) => set((state) => ({ text: state.text + content })),
+  setSources: (sources) => set({ sources, selectedSource: sources[0] ?? null }),
+  selectSource: (selectedSource) => set({ selectedSource }),
+  fail: (error) => set({ phase: 'error', error }),
+  reset: () => set(initial),
+}))
diff --git a/web/src/features/chat/useChatStream.ts b/web/src/features/chat/useChatStream.ts
new file mode 100644
index 0000000..8b4b14c
--- /dev/null
+++ b/web/src/features/chat/useChatStream.ts
@@ -0,0 +1,39 @@
+import { useCallback, useEffect, useRef } from 'react'
+
+import { streamSSE } from '../../lib/sse'
+import { useChatStreamStore } from './store'
+
+export function useChatStream(onDone: () => Promise<void>) {
+  const controllerRef = useRef<AbortController | null>(null)
+  const store = useChatStreamStore()
+
+  const abort = useCallback(() => controllerRef.current?.abort(), [])
+  const cancel = useCallback(() => {
+    controllerRef.current?.abort()
+    useChatStreamStore.getState().fail('已停止生成，可重新发送问题。')
+  }, [])
+
+  const send = useCallback(async (sessionId: string, query: string) => {
+    controllerRef.current?.abort()
+    const controller = new AbortController()
+    controllerRef.current = controller
+    store.start(query)
+    try {
+      await streamSSE('/api/v1/chat/stream', { session_id: sessionId, query }, (event) => {
+        if (event.event === 'status') store.setPhase(event.data.phase)
+        if (event.event === 'sources') store.setSources(event.data.sources)
+        if (event.event === 'token') store.appendText(event.data.content)
+        if (event.event === 'error') store.fail(event.data.message)
+      }, controller.signal)
+      if (!controller.signal.aborted && useChatStreamStore.getState().phase !== 'error') await onDone()
+    } catch (reason) {
+      if (controller.signal.aborted) return
+      store.fail(reason instanceof Error ? reason.message : '流式回答失败')
+    } finally {
+      if (controllerRef.current === controller) controllerRef.current = null
+    }
+  }, [onDone, store])
+
+  useEffect(() => abort, [abort])
+  return { send, cancel }
+}
diff --git a/web/src/index.css b/web/src/index.css
index bf36a1a..1106289 100644
--- a/web/src/index.css
+++ b/web/src/index.css
@@ -139,6 +139,79 @@ a { color: inherit; text-decoration: none; }
 .detail-pagination { padding-top: 9px; display: flex; align-items: center; justify-content: center; gap: 10px; color: #84908b; border-top: 1px solid var(--line); font-size: .65rem; }
 .evidence-drawer { position: fixed; inset: 0 0 0 auto; z-index: 51; width: min(390px, 92vw); background: #f0f3f1; box-shadow: -24px 0 80px rgba(0,0,0,.2); animation: drawer-in .25s ease; }
 
+.session-rail { min-height: 0; margin-top: 14px; display: flex; flex: 1; flex-direction: column; }
+.new-session { width: 100%; justify-content: flex-start; }
+.session-rail .nav-label { margin-top: 18px; }
+.session-list { min-height: 0; display: grid; align-content: start; gap: 4px; overflow-y: auto; scrollbar-width: thin; }
+.session-item { display: grid; grid-template-columns: minmax(0, 1fr) 30px; align-items: center; border-radius: 7px; color: #aebdb7; }
+.session-item > button:first-child { min-width: 0; padding: 8px 7px; color: inherit; border: 0; background: transparent; text-align: left; cursor: pointer; }
+.session-item strong, .session-item span { display: block; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.session-item strong { font-size: .68rem; font-weight: 650; }
+.session-item span { margin-top: 3px; color: #748b82; font-size: .56rem; }
+.session-item .button { width: 28px; height: 28px; opacity: 0; color: #91a49d; }
+.session-item:hover { background: rgba(255,255,255,.05); }
+.session-item:hover .button { opacity: 1; }
+.session-item--active { color: white; background: var(--forest-2); box-shadow: inset 3px 0 var(--ember); }
+.session-empty { margin: 8px; color: #70867d; font-size: .62rem; }
+
+.chat-workspace { display: grid; grid-template-columns: minmax(500px, 1fr) 330px; min-height: 100vh; }
+.chat-main { min-width: 0; height: 100vh; display: grid; grid-template-rows: auto minmax(0, 1fr) auto; background: rgba(250,250,247,.82); }
+.chat-header { min-height: 78px; padding: 20px clamp(20px, 3vw, 38px); display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); background: rgba(255,255,255,.62); backdrop-filter: blur(12px); }
+.chat-header h1 { margin: 5px 0 0; font-family: "Songti SC", Georgia, serif; font-size: 1.35rem; font-weight: 600; }
+.evidence-trigger { display: none; }
+.conversation-scroll { min-height: 0; padding: 26px clamp(20px, 4vw, 54px); overflow-y: auto; scroll-behavior: smooth; }
+.chat-empty { min-height: 100%; display: grid; place-content: center; justify-items: center; text-align: center; }
+.chat-empty > div { width: 57px; height: 57px; margin-bottom: 19px; display: grid; place-items: center; color: var(--ember); border: 1px solid #ddc9bd; border-radius: 50%; background: white; box-shadow: 0 16px 45px rgba(39,55,49,.08); }
+.chat-empty h2 { margin: 8px 0 7px; font-family: "Songti SC", Georgia, serif; font-size: 1.45rem; font-weight: 600; }
+.chat-empty > span { max-width: 360px; color: #7e8a85; font-size: .75rem; line-height: 1.7; }
+.message-list, .streaming-turn { display: grid; gap: 21px; }
+.streaming-turn { margin-top: 21px; }
+.message { display: grid; grid-template-columns: 28px minmax(0, 1fr); gap: 10px; align-items: start; animation: page-enter .25s ease both; }
+.message--user { margin-left: clamp(20px, 15%, 110px); grid-template-columns: minmax(0, 1fr); }
+.message--user .message-body { justify-self: end; max-width: 82%; padding: 10px 13px; border-radius: 12px 12px 3px 12px; background: #e2ebe7; }
+.message--user .message-avatar { display: none; }
+.message-avatar { width: 28px; height: 28px; display: grid; place-items: center; color: white; border-radius: 50%; background: var(--ember); box-shadow: 0 5px 14px rgba(172,86,53,.18); }
+.message-body { min-width: 0; color: #374943; }
+.message-body header { margin: 2px 0 7px; display: flex; align-items: baseline; gap: 8px; }
+.message-body header strong { font-size: .72rem; }
+.message-body header time { color: #929c98; font-size: .58rem; }
+.message-body p { margin: 0; white-space: pre-wrap; font-size: .82rem; line-height: 1.82; }
+.answer-copy { font-family: "Songti SC", Georgia, serif; }
+.citation { display: inline-flex; margin: 0 2px; padding: 1px 5px; color: #a75435; border: 1px solid #dfc1af; border-radius: 4px; background: #fff5ef; cursor: pointer; font-family: "Avenir Next", sans-serif; font-size: .62rem; font-weight: 800; vertical-align: .08em; }
+.citation--deleted { color: #8d9692; border-color: #d9dddb; background: #f0f1ee; cursor: default; }
+.failed-message { display: flex; align-items: center; gap: 7px; color: var(--danger); }
+.research-state { display: flex; align-items: center; gap: 8px; color: #73827c; font-family: "Avenir Next", sans-serif; font-size: .72rem !important; }
+.typing-cursor { display: inline-block; width: 2px; height: 1em; margin-left: 3px; background: var(--ember); animation: blink .8s step-end infinite; vertical-align: -.12em; }
+.pulse { color: var(--ember); animation: pulse 1.2s ease-in-out infinite; }
+.chat-composer { position: relative; margin: 0 clamp(20px, 4vw, 54px) 20px; padding: 10px 10px 24px 13px; display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: end; gap: 9px; border: 1px solid #cdd7d2; border-radius: 11px; background: white; box-shadow: 0 10px 35px rgba(37,54,47,.08); }
+.chat-composer textarea { width: 100%; min-height: 45px; max-height: 140px; padding: 5px 0; resize: none; color: var(--ink); border: 0; outline: 0; background: transparent; font-size: .8rem; line-height: 1.55; }
+.chat-composer textarea::placeholder { color: #9aa4a0; }
+.chat-composer small { position: absolute; bottom: 7px; left: 13px; color: #a0aaa6; font-size: .54rem; }
+.evidence-desktop { min-width: 0; border-left: 1px solid var(--line); background: #f0f3f1; }
+.evidence-panel { height: 100vh; padding: 22px 17px 16px; display: flex; flex-direction: column; overflow: hidden; }
+.evidence-header { min-height: 47px; display: grid; grid-template-columns: minmax(0, 1fr) auto auto; align-items: start; gap: 7px; }
+.evidence-header h2 { margin: 5px 0 0; font-family: "Songti SC", Georgia, serif; font-size: 1.15rem; font-weight: 600; }
+.evidence-header > span { margin-top: 7px; color: #82908a; font-size: .62rem; }
+.evidence-empty { flex: 1; display: grid; place-content: center; justify-items: center; gap: 7px; color: #85918c; text-align: center; }
+.evidence-empty svg { margin-bottom: 4px; color: var(--ember); }
+.evidence-empty strong { color: var(--ink); font-family: "Songti SC", Georgia, serif; }
+.evidence-empty span { max-width: 220px; font-size: .68rem; line-height: 1.6; }
+.source-list { max-height: 42%; margin: 16px 0 11px; display: grid; align-content: start; gap: 7px; overflow-y: auto; }
+.source-card { width: 100%; padding: 10px; display: grid; grid-template-columns: 18px minmax(0, 1fr); gap: 7px; color: #52625c; border: 1px solid #d8dfdb; border-radius: 8px; background: rgba(255,255,255,.64); cursor: pointer; text-align: left; }
+.source-card > svg { margin-top: 1px; color: var(--ember); }
+.source-card strong, .source-card small { display: block; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.source-card strong { color: #354a42; font-size: .68rem; }
+.source-card small { margin-top: 4px; color: #89948f; font-size: .58rem; }
+.source-card--active { border-color: #d2a78e; background: white; box-shadow: inset 3px 0 var(--ember), 0 6px 20px rgba(41,58,51,.05); }
+.source-detail { min-height: 0; flex: 1; padding: 14px; overflow-y: auto; color: #e7efeb; border-radius: 10px; background: var(--forest); }
+.source-detail header { display: flex; justify-content: space-between; gap: 10px; }
+.source-detail header strong { font-size: .68rem; }
+.source-detail header span { color: #9fb1aa; font-size: .57rem; }
+.source-detail p { margin: 12px 0 0; white-space: pre-wrap; color: #d8e2de; font-family: "Songti SC", Georgia, serif; font-size: .72rem; line-height: 1.85; }
+
+@keyframes blink { 50% { opacity: 0; } }
+@keyframes pulse { 50% { opacity: .45; transform: scale(.92); } }
+
 @keyframes spin { to { transform: rotate(360deg); } }
 @keyframes drawer-in { from { transform: translateX(100%); } }
 
@@ -160,6 +233,9 @@ a { color: inherit; text-decoration: none; }
   .documents-workspace { display: block; }
   .documents-detail-desktop { display: none; }
   .detail-trigger { display: inline-flex; }
+  .chat-workspace { display: block; }
+  .evidence-desktop { display: none; }
+  .evidence-trigger { display: inline-flex; }
 }
 
 @media (max-width: 640px) {
@@ -172,6 +248,11 @@ a { color: inherit; text-decoration: none; }
   .document-row { grid-template-columns: 40px minmax(0, 1fr); padding-right: 38px; }
   .document-row .status { grid-column: 2; justify-self: start; }
   .row-actions { grid-column: 2; }
+  .chat-main { height: calc(100vh - 58px); }
+  .chat-header { padding: 14px 16px; }
+  .conversation-scroll { padding: 20px 16px; }
+  .chat-composer { margin: 0 12px 12px; }
+  .message--user { margin-left: 16px; }
 }
 
 @media (prefers-reduced-motion: reduce) {