diff --git a/fe-admin/src/components/pe/AttachmentPreviewDialog.tsx b/fe-admin/src/components/pe/AttachmentPreviewDialog.tsx
new file mode 100644
index 0000000..85c9a01
--- /dev/null
+++ b/fe-admin/src/components/pe/AttachmentPreviewDialog.tsx
@@ -0,0 +1,97 @@
+import { useEffect, useState } from 'react'
+import { Loader2, AlertTriangle } from 'lucide-react'
+import { Dialog } from '@/components/ui/Dialog'
+import { Button } from '@/components/ui/Button'
+import { api } from '@/lib/api'
+
+/** Extensions hỗ trợ preview inline (PDF native + images native). Word/Excel
+ *  KHÔNG support — user phải download mở local Office. */
+const PREVIEWABLE_EXT = ['pdf', 'png', 'jpg', 'jpeg', 'webp', 'gif']
+
+export function isPreviewable(fileName: string): boolean {
+  const ext = fileName.toLowerCase().split('.').pop() ?? ''
+  return PREVIEWABLE_EXT.includes(ext)
+}
+
+type Props = {
+  open: boolean
+  evaluationId: string
+  attachmentId: string
+  fileName: string
+  onClose: () => void
+}
+
+/** Preview file inline qua BE endpoint `/view` (Content-Disposition: inline).
+ *  Fetch as blob → object URL → iframe (PDF) hoặc img (image).
+ *  Bearer auth qua axios api client (KHÔNG thể set iframe src trực tiếp vì
+ *  iframe không inherit Authorization header). */
+export function AttachmentPreviewDialog({
+  open, evaluationId, attachmentId, fileName, onClose,
+}: Props) {
+  const [blobUrl, setBlobUrl] = useState<string | null>(null)
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+
+  const ext = fileName.toLowerCase().split('.').pop() ?? ''
+  const isImage = ['png', 'jpg', 'jpeg', 'webp', 'gif'].includes(ext)
+
+  useEffect(() => {
+    if (!open) return
+    let cancelled = false
+    let currentUrl: string | null = null
+    setLoading(true)
+    setError(null)
+
+    api.get(`/purchase-evaluations/${evaluationId}/attachments/${attachmentId}/view`, {
+      responseType: 'blob',
+    })
+      .then(res => {
+        if (cancelled) return
+        currentUrl = window.URL.createObjectURL(res.data as Blob)
+        setBlobUrl(currentUrl)
+        setLoading(false)
+      })
+      .catch(err => {
+        if (cancelled) return
+        setError(err?.message ?? 'Lỗi tải file')
+        setLoading(false)
+      })
+
+    return () => {
+      cancelled = true
+      if (currentUrl) window.URL.revokeObjectURL(currentUrl)
+      setBlobUrl(null)
+    }
+  }, [open, evaluationId, attachmentId])
+
+  return (
+    <Dialog
+      open={open}
+      onClose={onClose}
+      title={`Xem file: ${fileName}`}
+      size="lg"
+      footer={<Button variant="outline" onClick={onClose}>Đóng</Button>}
+    >
+      <div className="h-[70vh] w-full bg-slate-100">
+        {loading && (
+          <div className="flex h-full items-center justify-center gap-2 text-slate-500">
+            <Loader2 className="h-5 w-5 animate-spin" />
+            <span>Đang tải file…</span>
+          </div>
+        )}
+        {error && !loading && (
+          <div className="flex h-full flex-col items-center justify-center gap-2 px-4 text-center text-red-600">
+            <AlertTriangle className="h-8 w-8" />
+            <div className="font-medium">Không tải được file</div>
+            <div className="text-xs text-red-500">{error}</div>
+          </div>
+        )}
+        {blobUrl && !loading && !error && (
+          isImage
+            ? <img src={blobUrl} alt={fileName} className="mx-auto h-full object-contain" />
+            : <iframe src={blobUrl} title={fileName} className="h-full w-full border-0" />
+        )}
+      </div>
+    </Dialog>
+  )
+}
diff --git a/fe-admin/src/components/pe/PeDetailTabs.tsx b/fe-admin/src/components/pe/PeDetailTabs.tsx
index 6b795ae..55173e5 100644
--- a/fe-admin/src/components/pe/PeDetailTabs.tsx
+++ b/fe-admin/src/components/pe/PeDetailTabs.tsx
@@ -6,7 +6,7 @@ import { useEffect, useRef, useState } from 'react'
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
 import { useNavigate } from 'react-router-dom'
 import { toast } from 'sonner'
-import { Check, ChevronDown, ChevronRight, Paperclip, Pencil, Plus, Trash2, Upload } from 'lucide-react'
+import { Check, ChevronDown, ChevronRight, Download, Eye, Paperclip, Pencil, Plus, Trash2, Upload, Wallet } from 'lucide-react'
 import { Button } from '@/components/ui/Button'
 import { Dialog } from '@/components/ui/Dialog'
 import { Input } from '@/components/ui/Input'
@@ -16,6 +16,7 @@ import { api } from '@/lib/api'
 import { getErrorMessage } from '@/lib/apiError'
 import { cn } from '@/lib/cn'
 import { useAuth } from '@/contexts/AuthContext'
+import { AttachmentPreviewDialog, isPreviewable } from './AttachmentPreviewDialog'
 import {
   PeAttachmentPurpose,
   PeAttachmentPurposeLabel,
@@ -234,6 +235,12 @@ export function PeDetailTabs({
             ? <LevelOpinionsSectionV2 ev={evaluation} />
             : <DepartmentOpinionsSection ev={evaluation} readOnly={opinionsReadOnly} />}
         </Section>
+        {/* S22+4 — Feature 2: Section "Điều chỉnh ngân sách" cho phép Drafter
+            (Nháp/Trả lại) HOẶC Approver currentLevel (Đang duyệt) HOẶC Admin
+            sửa Budget link / Manual amount. BE PATCH /budget-adjust riêng. */}
+        <Section title="5. Điều chỉnh ngân sách">
+          <BudgetAdjustSection ev={evaluation} readOnly={readOnly} />
+        </Section>
       </div>
 
       {/* Action bar bottom — workspace mode + canEdit + !readOnly. 3 nút:
@@ -954,6 +961,183 @@ function BudgetFieldRow({ ev, readOnly }: { ev: PeDetailBundle; readOnly: boolea
   )
 }
 
+// ===== Section "Điều chỉnh ngân sách" (S22+4 — Feature 2) =====
+// Cho phép Drafter (DangSoanThao/TraLai) HOẶC Approver currentLevel (ChoDuyet)
+// HOẶC Admin sửa BudgetId + BudgetManualName + BudgetManualAmount qua endpoint
+// PATCH /budget-adjust riêng. Audit changelog tự động.
+function BudgetAdjustSection({ ev, readOnly }: { ev: PeDetailBundle; readOnly: boolean }) {
+  const { user: currentUser } = useAuth()
+  const qc = useQueryClient()
+  const [editing, setEditing] = useState(false)
+
+  const isAdmin = currentUser?.roles?.includes('Admin') ?? false
+  const isDrafter = currentUser?.id != null && ev.drafterUserId === currentUser.id
+  const isDrafterPhase = ev.phase === PurchaseEvaluationPhase.DangSoanThao
+    || ev.phase === PurchaseEvaluationPhase.TraLai
+  // Approver currentLevel match — phase ChoDuyet + actor in current approval level
+  const actorInCurrentLevel = ev.currentApproval?.approvers?.some(a => a.userId === currentUser?.id) ?? false
+  const isApproverChoDuyet = ev.phase === PurchaseEvaluationPhase.ChoDuyet && actorInCurrentLevel
+
+  const canAdjust = !readOnly && (isAdmin || (isDrafter && isDrafterPhase) || isApproverChoDuyet)
+
+  const initialManual = (ev.budgetManualName !== null || ev.budgetManualAmount !== null) && !ev.budgetId
+  const [manualMode, setManualMode] = useState(initialManual)
+  const [budgetId, setBudgetId] = useState(ev.budgetId ?? '')
+  const [manualAmount, setManualAmount] = useState(ev.budgetManualAmount ?? 0)
+  const [manualName, setManualName] = useState(ev.budgetManualName ?? '')
+
+  const eligibleBudgets = useQuery({
+    queryKey: ['eligible-budgets-adjust', ev.projectId],
+    queryFn: async () => (await api.get<Paged<BudgetListItem>>('/budgets', {
+      params: { pageSize: 100, projectId: ev.projectId, phase: BudgetPhase.DaDuyet },
+    })).data.items,
+    enabled: editing && canAdjust,
+  })
+
+  const adjustMut = useMutation({
+    mutationFn: async () => {
+      const payload = manualMode
+        ? { budgetId: null, budgetManualName: manualName || null, budgetManualAmount: manualAmount > 0 ? manualAmount : null }
+        : { budgetId: budgetId || null, budgetManualName: null, budgetManualAmount: null }
+      await api.patch(`/purchase-evaluations/${ev.id}/budget-adjust`, payload)
+    },
+    onSuccess: () => {
+      toast.success('Đã điều chỉnh ngân sách')
+      qc.invalidateQueries({ queryKey: ['pe-detail', ev.id] })
+      qc.invalidateQueries({ queryKey: ['pe-list'] })
+      setEditing(false)
+    },
+    onError: e => toast.error(getErrorMessage(e)),
+  })
+
+  // History defer S22+5 — changelog fetch separate endpoint, KHÔNG có trong
+  // PeDetailBundle. UAT user xem ở Panel "Lịch sử thay đổi" thông qua tab History.
+
+  // Display read mode
+  const displayLink = ev.budget ? (
+    <span>
+      <span className="font-mono text-[11px] text-brand-700">{ev.budget.maNganSach ?? '—'}</span>
+      {' · '}{ev.budget.tenNganSach}
+      {' · '}<span className="font-semibold text-slate-900">{ev.budget.tongNganSach.toLocaleString('vi-VN')} đ</span>
+    </span>
+  ) : (ev.budgetManualAmount != null || ev.budgetManualName) ? (
+    <span>
+      {ev.budgetManualName && <span>{ev.budgetManualName}</span>}
+      {ev.budgetManualName && ev.budgetManualAmount != null && ' · '}
+      {ev.budgetManualAmount != null && (
+        <span className="font-semibold text-slate-900">{ev.budgetManualAmount.toLocaleString('vi-VN')} đ</span>
+      )}
+      <span className="ml-2 rounded bg-slate-100 px-1.5 py-0.5 text-[10px] text-slate-500">nhập tay</span>
+    </span>
+  ) : <span className="italic text-slate-400">Chưa có ngân sách</span>
+
+  return (
+    <div className="space-y-3">
+      {/* Read mode + Edit toggle */}
+      {!editing && (
+        <div className="flex items-start justify-between gap-3 rounded border border-emerald-200 bg-emerald-50/40 px-3 py-2">
+          <div className="flex items-start gap-2">
+            <Wallet className="mt-0.5 h-4 w-4 shrink-0 text-emerald-600" />
+            <div className="text-sm text-slate-700">{displayLink}</div>
+          </div>
+          {canAdjust && (
+            <Button
+              onClick={() => {
+                setManualMode(initialManual)
+                setBudgetId(ev.budgetId ?? '')
+                setManualAmount(ev.budgetManualAmount ?? 0)
+                setManualName(ev.budgetManualName ?? '')
+                setEditing(true)
+              }}
+              variant="ghost"
+              className="h-7 shrink-0 px-2 text-xs"
+            >
+              <Pencil className="h-3 w-3" /> Điều chỉnh
+            </Button>
+          )}
+        </div>
+      )}
+
+      {/* Edit mode */}
+      {editing && canAdjust && (
+        <div className="space-y-3 rounded border border-emerald-300 bg-emerald-50/30 p-3">
+          {isApproverChoDuyet && (
+            <div className="rounded border border-amber-200 bg-amber-50 px-2 py-1.5 text-[11px] text-amber-800">
+              ⓘ Bạn đang điều chỉnh ngân sách lúc phiếu đang duyệt — thay đổi sẽ được ghi vào lịch sử.
+            </div>
+          )}
+          <label className="inline-flex cursor-pointer items-center gap-1.5 text-[11px] text-slate-600">
+            <input
+              type="checkbox"
+              checked={manualMode}
+              onChange={e => setManualMode(e.target.checked)}
+              className="h-3.5 w-3.5 rounded border-slate-300"
+            />
+            Nhập tay (không link Budget)
+          </label>
+          {!manualMode ? (
+            <div>
+              <Label className="text-[11px]">Chọn Budget từ danh sách</Label>
+              <Select value={budgetId} onChange={e => setBudgetId(e.target.value)} className="text-sm">
+                <option value="">— (huỷ link)</option>
+                {eligibleBudgets.data?.map(b => (
+                  <option key={b.id} value={b.id}>
+                    {b.maNganSach ?? '—'} · {b.tenNganSach} · {b.tongNganSach.toLocaleString('vi-VN')} đ
+                  </option>
+                ))}
+              </Select>
+            </div>
+          ) : (
+            <div className="grid gap-2 md:grid-cols-2">
+              <div>
+                <Label className="text-[11px]">Tên (không bắt buộc)</Label>
+                <Input
+                  value={manualName}
+                  onChange={e => setManualName(e.target.value)}
+                  placeholder="vd Ngân sách dự phòng Q2/2026"
+                  className="text-sm"
+                />
+              </div>
+              <div>
+                <Label className="text-[11px]">Số tiền (VND)</Label>
+                <div className="relative">
+                  <Input
+                    type="text"
+                    inputMode="numeric"
+                    value={formatVndInput(manualAmount)}
+                    onChange={e => setManualAmount(parseVnd(e.target.value))}
+                    placeholder="0"
+                    className="pr-10 font-mono text-right text-sm"
+                  />
+                  <span className="pointer-events-none absolute inset-y-0 right-3 flex items-center text-[12px] font-medium text-slate-500">đ</span>
+                </div>
+              </div>
+            </div>
+          )}
+          <div className="flex items-center justify-end gap-2">
+            <Button
+              variant="ghost"
+              onClick={() => setEditing(false)}
+              className="h-7 px-3 text-xs"
+            >
+              Hủy
+            </Button>
+            <Button
+              onClick={() => adjustMut.mutate()}
+              disabled={adjustMut.isPending}
+              className="h-7 px-3 text-xs"
+            >
+              {adjustMut.isPending ? 'Đang lưu…' : 'Lưu điều chỉnh'}
+            </Button>
+          </div>
+        </div>
+      )}
+
+      {/* History defer S22+5 — UAT user xem Panel 3 "Lịch sử thay đổi" */}
+    </div>
+  )
+}
+
 // ===== Section 2 — Chọn NCC/TP (spec: a/b/c/d) =====
 function ChonNccSection({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: boolean }) {
   const canCreateContract = !readOnly && ev.phase === PurchaseEvaluationPhase.DaDuyet && !ev.contractId && ev.selectedSupplierId
@@ -1903,6 +2087,7 @@ function SupplierAttachmentsCell({
 }) {
   const qc = useQueryClient()
   const fileInputRef = useRef<HTMLInputElement>(null)
+  const [previewAtt, setPreviewAtt] = useState<PeAttachment | null>(null)
 
   const upload = useMutation({
     mutationFn: async (file: File) => {
@@ -1965,17 +2150,29 @@ function SupplierAttachmentsCell({
       {attachments.map(a => (
         <div key={a.id} className="flex items-center gap-1.5 rounded bg-slate-50 px-1.5 py-1 text-[11px]">
           <Paperclip className="h-3 w-3 shrink-0 text-slate-400" />
-          <button
-            onClick={() => download(a)}
-            className="min-w-0 flex-1 truncate text-left text-slate-700 hover:text-brand-700 hover:underline"
-            title={a.fileName}
-          >
+          <span className="min-w-0 flex-1 truncate text-slate-700" title={a.fileName}>
             {a.fileName}
-          </button>
+          </span>
           <span className="shrink-0 text-[10px] text-slate-400">{fmtSize(a.fileSize)}</span>
           <span className="shrink-0 rounded bg-slate-200 px-1 text-[9px] text-slate-600">
             {PeAttachmentPurposeLabel[a.purpose] ?? ''}
           </span>
+          {isPreviewable(a.fileName) && (
+            <button
+              onClick={() => setPreviewAtt(a)}
+              className="shrink-0 rounded px-1 text-violet-600 hover:bg-violet-50"
+              title="Xem trước"
+            >
+              <Eye className="h-3 w-3" />
+            </button>
+          )}
+          <button
+            onClick={() => download(a)}
+            className="shrink-0 rounded px-1 text-brand-600 hover:bg-brand-50"
+            title="Tải xuống"
+          >
+            <Download className="h-3 w-3" />
+          </button>
           {!readOnly && (
             <button
               onClick={() => { if (confirm(`Xóa "${a.fileName}"?`)) del.mutate(a.id) }}
@@ -1987,6 +2184,15 @@ function SupplierAttachmentsCell({
           )}
         </div>
       ))}
+      {previewAtt && (
+        <AttachmentPreviewDialog
+          open
+          evaluationId={evaluationId}
+          attachmentId={previewAtt.id}
+          fileName={previewAtt.fileName}
+          onClose={() => setPreviewAtt(null)}
+        />
+      )}
       {!readOnly && (
         <div>
           <input
@@ -2025,6 +2231,7 @@ function GeneralAttachmentsSection({
 }) {
   const qc = useQueryClient()
   const fileInputRef = useRef<HTMLInputElement>(null)
+  const [previewAtt, setPreviewAtt] = useState<PeAttachment | null>(null)
 
   const upload = useMutation({
     mutationFn: async (file: File) => {
@@ -2097,13 +2304,9 @@ function GeneralAttachmentsSection({
               className="flex items-center gap-2 rounded border border-slate-200 bg-white px-3 py-2 text-sm shadow-sm"
             >
               <Paperclip className="h-4 w-4 shrink-0 text-brand-500" />
-              <button
-                onClick={() => download(a)}
-                className="min-w-0 flex-1 truncate text-left font-medium text-slate-800 hover:text-brand-700 hover:underline"
-                title={a.fileName}
-              >
+              <span className="min-w-0 flex-1 truncate font-medium text-slate-800" title={a.fileName}>
                 {a.fileName}
-              </button>
+              </span>
               <span className="shrink-0 text-[11px] text-slate-500">{fmtSize(a.fileSize)}</span>
               <span className="shrink-0 rounded bg-brand-50 px-1.5 py-0.5 text-[10px] text-brand-700">
                 {PeAttachmentPurposeLabel[a.purpose] ?? 'Khác'}
@@ -2111,6 +2314,22 @@ function GeneralAttachmentsSection({
               <span className="shrink-0 text-[10px] text-slate-400">
                 {new Date(a.createdAt).toLocaleDateString('vi-VN')}
               </span>
+              {isPreviewable(a.fileName) && (
+                <button
+                  onClick={() => setPreviewAtt(a)}
+                  className="shrink-0 rounded p-1 text-violet-600 hover:bg-violet-50"
+                  title="Xem trước"
+                >
+                  <Eye className="h-3.5 w-3.5" />
+                </button>
+              )}
+              <button
+                onClick={() => download(a)}
+                className="shrink-0 rounded p-1 text-brand-600 hover:bg-brand-50"
+                title="Tải xuống"
+              >
+                <Download className="h-3.5 w-3.5" />
+              </button>
               {!readOnly && (
                 <button
                   onClick={() => { if (confirm(`Xóa "${a.fileName}"?`)) del.mutate(a.id) }}
@@ -2124,6 +2343,15 @@ function GeneralAttachmentsSection({
           ))}
         </div>
       )}
+      {previewAtt && (
+        <AttachmentPreviewDialog
+          open
+          evaluationId={evaluationId}
+          attachmentId={previewAtt.id}
+          fileName={previewAtt.fileName}
+          onClose={() => setPreviewAtt(null)}
+        />
+      )}
       {!readOnly && (
         <div>
           <input
diff --git a/fe-user/src/components/pe/AttachmentPreviewDialog.tsx b/fe-user/src/components/pe/AttachmentPreviewDialog.tsx
new file mode 100644
index 0000000..85c9a01
--- /dev/null
+++ b/fe-user/src/components/pe/AttachmentPreviewDialog.tsx
@@ -0,0 +1,97 @@
+import { useEffect, useState } from 'react'
+import { Loader2, AlertTriangle } from 'lucide-react'
+import { Dialog } from '@/components/ui/Dialog'
+import { Button } from '@/components/ui/Button'
+import { api } from '@/lib/api'
+
+/** Extensions hỗ trợ preview inline (PDF native + images native). Word/Excel
+ *  KHÔNG support — user phải download mở local Office. */
+const PREVIEWABLE_EXT = ['pdf', 'png', 'jpg', 'jpeg', 'webp', 'gif']
+
+export function isPreviewable(fileName: string): boolean {
+  const ext = fileName.toLowerCase().split('.').pop() ?? ''
+  return PREVIEWABLE_EXT.includes(ext)
+}
+
+type Props = {
+  open: boolean
+  evaluationId: string
+  attachmentId: string
+  fileName: string
+  onClose: () => void
+}
+
+/** Preview file inline qua BE endpoint `/view` (Content-Disposition: inline).
+ *  Fetch as blob → object URL → iframe (PDF) hoặc img (image).
+ *  Bearer auth qua axios api client (KHÔNG thể set iframe src trực tiếp vì
+ *  iframe không inherit Authorization header). */
+export function AttachmentPreviewDialog({
+  open, evaluationId, attachmentId, fileName, onClose,
+}: Props) {
+  const [blobUrl, setBlobUrl] = useState<string | null>(null)
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+
+  const ext = fileName.toLowerCase().split('.').pop() ?? ''
+  const isImage = ['png', 'jpg', 'jpeg', 'webp', 'gif'].includes(ext)
+
+  useEffect(() => {
+    if (!open) return
+    let cancelled = false
+    let currentUrl: string | null = null
+    setLoading(true)
+    setError(null)
+
+    api.get(`/purchase-evaluations/${evaluationId}/attachments/${attachmentId}/view`, {
+      responseType: 'blob',
+    })
+      .then(res => {
+        if (cancelled) return
+        currentUrl = window.URL.createObjectURL(res.data as Blob)
+        setBlobUrl(currentUrl)
+        setLoading(false)
+      })
+      .catch(err => {
+        if (cancelled) return
+        setError(err?.message ?? 'Lỗi tải file')
+        setLoading(false)
+      })
+
+    return () => {
+      cancelled = true
+      if (currentUrl) window.URL.revokeObjectURL(currentUrl)
+      setBlobUrl(null)
+    }
+  }, [open, evaluationId, attachmentId])
+
+  return (
+    <Dialog
+      open={open}
+      onClose={onClose}
+      title={`Xem file: ${fileName}`}
+      size="lg"
+      footer={<Button variant="outline" onClick={onClose}>Đóng</Button>}
+    >
+      <div className="h-[70vh] w-full bg-slate-100">
+        {loading && (
+          <div className="flex h-full items-center justify-center gap-2 text-slate-500">
+            <Loader2 className="h-5 w-5 animate-spin" />
+            <span>Đang tải file…</span>
+          </div>
+        )}
+        {error && !loading && (
+          <div className="flex h-full flex-col items-center justify-center gap-2 px-4 text-center text-red-600">
+            <AlertTriangle className="h-8 w-8" />
+            <div className="font-medium">Không tải được file</div>
+            <div className="text-xs text-red-500">{error}</div>
+          </div>
+        )}
+        {blobUrl && !loading && !error && (
+          isImage
+            ? <img src={blobUrl} alt={fileName} className="mx-auto h-full object-contain" />
+            : <iframe src={blobUrl} title={fileName} className="h-full w-full border-0" />
+        )}
+      </div>
+    </Dialog>
+  )
+}
diff --git a/fe-user/src/components/pe/PeDetailTabs.tsx b/fe-user/src/components/pe/PeDetailTabs.tsx
index ffd228f..b2891d7 100644
--- a/fe-user/src/components/pe/PeDetailTabs.tsx
+++ b/fe-user/src/components/pe/PeDetailTabs.tsx
@@ -6,7 +6,8 @@ import { useEffect, useRef, useState } from 'react'
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
 import { useNavigate } from 'react-router-dom'
 import { toast } from 'sonner'
-import { Check, ChevronDown, ChevronRight, Paperclip, Pencil, Plus, Trash2, Upload } from 'lucide-react'
+import { Check, ChevronDown, ChevronRight, Download, Eye, Paperclip, Pencil, Plus, Trash2, Upload, Wallet } from 'lucide-react'
+import { AttachmentPreviewDialog, isPreviewable } from './AttachmentPreviewDialog'
 import { Button } from '@/components/ui/Button'
 import { Dialog } from '@/components/ui/Dialog'
 import { Input } from '@/components/ui/Input'
@@ -240,6 +241,12 @@ export function PeDetailTabs({
             ? <LevelOpinionsSectionV2 ev={evaluation} />
             : <DepartmentOpinionsSection ev={evaluation} readOnly={opinionsReadOnly} />}
         </Section>
+        {/* S22+4 — Feature 2: Section "Điều chỉnh ngân sách" (mirror fe-admin).
+            Drafter (Nháp/Trả lại) HOẶC Approver currentLevel (Đang duyệt) HOẶC
+            Admin sửa Budget link / Manual amount. BE PATCH /budget-adjust. */}
+        <Section title="5. Điều chỉnh ngân sách">
+          <BudgetAdjustSection ev={evaluation} readOnly={readOnly} />
+        </Section>
       </div>
 
       {/* Action bar bottom — workspace mode + canEdit + !readOnly. 3 nút:
@@ -961,6 +968,174 @@ function BudgetFieldRow({ ev, readOnly }: { ev: PeDetailBundle; readOnly: boolea
   )
 }
 
+// ===== Section "Điều chỉnh ngân sách" (S22+4 — Feature 2) =====
+// Mirror fe-admin BudgetAdjustSection — Drafter (Nháp/Trả lại) HOẶC Approver
+// currentLevel (Đang duyệt) HOẶC Admin sửa Budget link / Manual amount via
+// PATCH /budget-adjust riêng. Audit changelog tự động.
+function BudgetAdjustSection({ ev, readOnly }: { ev: PeDetailBundle; readOnly: boolean }) {
+  const { user: currentUser } = useAuth()
+  const qc = useQueryClient()
+  const [editing, setEditing] = useState(false)
+
+  const isAdmin = currentUser?.roles?.includes('Admin') ?? false
+  const isDrafter = currentUser?.id != null && ev.drafterUserId === currentUser.id
+  const isDrafterPhase = ev.phase === PurchaseEvaluationPhase.DangSoanThao
+    || ev.phase === PurchaseEvaluationPhase.TraLai
+  const actorInCurrentLevel = ev.currentApproval?.approvers?.some(a => a.userId === currentUser?.id) ?? false
+  const isApproverChoDuyet = ev.phase === PurchaseEvaluationPhase.ChoDuyet && actorInCurrentLevel
+
+  const canAdjust = !readOnly && (isAdmin || (isDrafter && isDrafterPhase) || isApproverChoDuyet)
+
+  const initialManual = (ev.budgetManualName !== null || ev.budgetManualAmount !== null) && !ev.budgetId
+  const [manualMode, setManualMode] = useState(initialManual)
+  const [budgetId, setBudgetId] = useState(ev.budgetId ?? '')
+  const [manualAmount, setManualAmount] = useState(ev.budgetManualAmount ?? 0)
+  const [manualName, setManualName] = useState(ev.budgetManualName ?? '')
+
+  const eligibleBudgets = useQuery({
+    queryKey: ['eligible-budgets-adjust', ev.projectId],
+    queryFn: async () => (await api.get<Paged<BudgetListItem>>('/budgets', {
+      params: { pageSize: 100, projectId: ev.projectId, phase: BudgetPhase.DaDuyet },
+    })).data.items,
+    enabled: editing && canAdjust,
+  })
+
+  const adjustMut = useMutation({
+    mutationFn: async () => {
+      const payload = manualMode
+        ? { budgetId: null, budgetManualName: manualName || null, budgetManualAmount: manualAmount > 0 ? manualAmount : null }
+        : { budgetId: budgetId || null, budgetManualName: null, budgetManualAmount: null }
+      await api.patch(`/purchase-evaluations/${ev.id}/budget-adjust`, payload)
+    },
+    onSuccess: () => {
+      toast.success('Đã điều chỉnh ngân sách')
+      qc.invalidateQueries({ queryKey: ['pe-detail', ev.id] })
+      qc.invalidateQueries({ queryKey: ['pe-list'] })
+      setEditing(false)
+    },
+    onError: e => toast.error(getErrorMessage(e)),
+  })
+
+  const displayLink = ev.budget ? (
+    <span>
+      <span className="font-mono text-[11px] text-brand-700">{ev.budget.maNganSach ?? '—'}</span>
+      {' · '}{ev.budget.tenNganSach}
+      {' · '}<span className="font-semibold text-slate-900">{ev.budget.tongNganSach.toLocaleString('vi-VN')} đ</span>
+    </span>
+  ) : (ev.budgetManualAmount != null || ev.budgetManualName) ? (
+    <span>
+      {ev.budgetManualName && <span>{ev.budgetManualName}</span>}
+      {ev.budgetManualName && ev.budgetManualAmount != null && ' · '}
+      {ev.budgetManualAmount != null && (
+        <span className="font-semibold text-slate-900">{ev.budgetManualAmount.toLocaleString('vi-VN')} đ</span>
+      )}
+      <span className="ml-2 rounded bg-slate-100 px-1.5 py-0.5 text-[10px] text-slate-500">nhập tay</span>
+    </span>
+  ) : <span className="italic text-slate-400">Chưa có ngân sách</span>
+
+  return (
+    <div className="space-y-3">
+      {!editing && (
+        <div className="flex items-start justify-between gap-3 rounded border border-emerald-200 bg-emerald-50/40 px-3 py-2">
+          <div className="flex items-start gap-2">
+            <Wallet className="mt-0.5 h-4 w-4 shrink-0 text-emerald-600" />
+            <div className="text-sm text-slate-700">{displayLink}</div>
+          </div>
+          {canAdjust && (
+            <Button
+              onClick={() => {
+                setManualMode(initialManual)
+                setBudgetId(ev.budgetId ?? '')
+                setManualAmount(ev.budgetManualAmount ?? 0)
+                setManualName(ev.budgetManualName ?? '')
+                setEditing(true)
+              }}
+              variant="ghost"
+              className="h-7 shrink-0 px-2 text-xs"
+            >
+              <Pencil className="h-3 w-3" /> Điều chỉnh
+            </Button>
+          )}
+        </div>
+      )}
+
+      {editing && canAdjust && (
+        <div className="space-y-3 rounded border border-emerald-300 bg-emerald-50/30 p-3">
+          {isApproverChoDuyet && (
+            <div className="rounded border border-amber-200 bg-amber-50 px-2 py-1.5 text-[11px] text-amber-800">
+              ⓘ Bạn đang điều chỉnh ngân sách lúc phiếu đang duyệt — thay đổi sẽ được ghi vào lịch sử.
+            </div>
+          )}
+          <label className="inline-flex cursor-pointer items-center gap-1.5 text-[11px] text-slate-600">
+            <input
+              type="checkbox"
+              checked={manualMode}
+              onChange={e => setManualMode(e.target.checked)}
+              className="h-3.5 w-3.5 rounded border-slate-300"
+            />
+            Nhập tay (không link Budget)
+          </label>
+          {!manualMode ? (
+            <div>
+              <Label className="text-[11px]">Chọn Budget từ danh sách</Label>
+              <Select value={budgetId} onChange={e => setBudgetId(e.target.value)} className="text-sm">
+                <option value="">— (huỷ link)</option>
+                {eligibleBudgets.data?.map(b => (
+                  <option key={b.id} value={b.id}>
+                    {b.maNganSach ?? '—'} · {b.tenNganSach} · {b.tongNganSach.toLocaleString('vi-VN')} đ
+                  </option>
+                ))}
+              </Select>
+            </div>
+          ) : (
+            <div className="grid gap-2 md:grid-cols-2">
+              <div>
+                <Label className="text-[11px]">Tên (không bắt buộc)</Label>
+                <Input
+                  value={manualName}
+                  onChange={e => setManualName(e.target.value)}
+                  placeholder="vd Ngân sách dự phòng Q2/2026"
+                  className="text-sm"
+                />
+              </div>
+              <div>
+                <Label className="text-[11px]">Số tiền (VND)</Label>
+                <div className="relative">
+                  <Input
+                    type="text"
+                    inputMode="numeric"
+                    value={formatVndInput(manualAmount)}
+                    onChange={e => setManualAmount(parseVnd(e.target.value))}
+                    placeholder="0"
+                    className="pr-10 font-mono text-right text-sm"
+                  />
+                  <span className="pointer-events-none absolute inset-y-0 right-3 flex items-center text-[12px] font-medium text-slate-500">đ</span>
+                </div>
+              </div>
+            </div>
+          )}
+          <div className="flex items-center justify-end gap-2">
+            <Button
+              variant="ghost"
+              onClick={() => setEditing(false)}
+              className="h-7 px-3 text-xs"
+            >
+              Hủy
+            </Button>
+            <Button
+              onClick={() => adjustMut.mutate()}
+              disabled={adjustMut.isPending}
+              className="h-7 px-3 text-xs"
+            >
+              {adjustMut.isPending ? 'Đang lưu…' : 'Lưu điều chỉnh'}
+            </Button>
+          </div>
+        </div>
+      )}
+    </div>
+  )
+}
+
 // ===== Section 2 — Chọn NCC/TP (spec: a/b/c/d) =====
 function ChonNccSection({ ev, readOnly = false }: { ev: PeDetailBundle; readOnly?: boolean }) {
   const canCreateContract = !readOnly && ev.phase === PurchaseEvaluationPhase.DaDuyet && !ev.contractId && ev.selectedSupplierId
@@ -1908,6 +2083,7 @@ function SupplierAttachmentsCell({
 }) {
   const qc = useQueryClient()
   const fileInputRef = useRef<HTMLInputElement>(null)
+  const [previewAtt, setPreviewAtt] = useState<PeAttachment | null>(null)
 
   const upload = useMutation({
     mutationFn: async (file: File) => {
@@ -1970,17 +2146,29 @@ function SupplierAttachmentsCell({
       {attachments.map(a => (
         <div key={a.id} className="flex items-center gap-1.5 rounded bg-slate-50 px-1.5 py-1 text-[11px]">
           <Paperclip className="h-3 w-3 shrink-0 text-slate-400" />
-          <button
-            onClick={() => download(a)}
-            className="min-w-0 flex-1 truncate text-left text-slate-700 hover:text-brand-700 hover:underline"
-            title={a.fileName}
-          >
+          <span className="min-w-0 flex-1 truncate text-slate-700" title={a.fileName}>
             {a.fileName}
-          </button>
+          </span>
           <span className="shrink-0 text-[10px] text-slate-400">{fmtSize(a.fileSize)}</span>
           <span className="shrink-0 rounded bg-slate-200 px-1 text-[9px] text-slate-600">
             {PeAttachmentPurposeLabel[a.purpose] ?? ''}
           </span>
+          {isPreviewable(a.fileName) && (
+            <button
+              onClick={() => setPreviewAtt(a)}
+              className="shrink-0 rounded px-1 text-violet-600 hover:bg-violet-50"
+              title="Xem trước"
+            >
+              <Eye className="h-3 w-3" />
+            </button>
+          )}
+          <button
+            onClick={() => download(a)}
+            className="shrink-0 rounded px-1 text-brand-600 hover:bg-brand-50"
+            title="Tải xuống"
+          >
+            <Download className="h-3 w-3" />
+          </button>
           {!readOnly && (
             <button
               onClick={() => { if (confirm(`Xóa "${a.fileName}"?`)) del.mutate(a.id) }}
@@ -1992,6 +2180,15 @@ function SupplierAttachmentsCell({
           )}
         </div>
       ))}
+      {previewAtt && (
+        <AttachmentPreviewDialog
+          open
+          evaluationId={evaluationId}
+          attachmentId={previewAtt.id}
+          fileName={previewAtt.fileName}
+          onClose={() => setPreviewAtt(null)}
+        />
+      )}
       {!readOnly && (
         <div>
           <input
@@ -2030,6 +2227,7 @@ function GeneralAttachmentsSection({
 }) {
   const qc = useQueryClient()
   const fileInputRef = useRef<HTMLInputElement>(null)
+  const [previewAtt, setPreviewAtt] = useState<PeAttachment | null>(null)
 
   const upload = useMutation({
     mutationFn: async (file: File) => {
@@ -2102,13 +2300,9 @@ function GeneralAttachmentsSection({
               className="flex items-center gap-2 rounded border border-slate-200 bg-white px-3 py-2 text-sm shadow-sm"
             >
               <Paperclip className="h-4 w-4 shrink-0 text-brand-500" />
-              <button
-                onClick={() => download(a)}
-                className="min-w-0 flex-1 truncate text-left font-medium text-slate-800 hover:text-brand-700 hover:underline"
-                title={a.fileName}
-              >
+              <span className="min-w-0 flex-1 truncate font-medium text-slate-800" title={a.fileName}>
                 {a.fileName}
-              </button>
+              </span>
               <span className="shrink-0 text-[11px] text-slate-500">{fmtSize(a.fileSize)}</span>
               <span className="shrink-0 rounded bg-brand-50 px-1.5 py-0.5 text-[10px] text-brand-700">
                 {PeAttachmentPurposeLabel[a.purpose] ?? 'Khác'}
@@ -2116,6 +2310,22 @@ function GeneralAttachmentsSection({
               <span className="shrink-0 text-[10px] text-slate-400">
                 {new Date(a.createdAt).toLocaleDateString('vi-VN')}
               </span>
+              {isPreviewable(a.fileName) && (
+                <button
+                  onClick={() => setPreviewAtt(a)}
+                  className="shrink-0 rounded p-1 text-violet-600 hover:bg-violet-50"
+                  title="Xem trước"
+                >
+                  <Eye className="h-3.5 w-3.5" />
+                </button>
+              )}
+              <button
+                onClick={() => download(a)}
+                className="shrink-0 rounded p-1 text-brand-600 hover:bg-brand-50"
+                title="Tải xuống"
+              >
+                <Download className="h-3.5 w-3.5" />
+              </button>
               {!readOnly && (
                 <button
                   onClick={() => { if (confirm(`Xóa "${a.fileName}"?`)) del.mutate(a.id) }}
@@ -2129,6 +2339,15 @@ function GeneralAttachmentsSection({
           ))}
         </div>
       )}
+      {previewAtt && (
+        <AttachmentPreviewDialog
+          open
+          evaluationId={evaluationId}
+          attachmentId={previewAtt.id}
+          fileName={previewAtt.fileName}
+          onClose={() => setPreviewAtt(null)}
+        />
+      )}
       {!readOnly && (
         <div>
           <input