diff --git a/README.md b/README.md
index 14caa36..93c72d4 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,7 @@ xcodebuild -project reimburse.xcodeproj -scheme reimburse \
 
 在工具栏点击“报销模板”，或点击材料扫描页、个人报销单弹窗中的“选择模板 / 查看、更换”。也可以直接从访达将一个 `.xlsx` 文件拖到模板卡片或模板窗口上方的虚线区域；拖入时高亮，处理中不接受重复导入。不接受文件夹、多个文件或网页链接，失败时原模板保持不变。
 
-模板窗口左侧显示 Excel 原表，右侧显示识别到的工作表、明细范围和收款位置。核对后点击“确认位置，使用此模板”。不再默认展示整屏地址输入框；仅在识别不正确时打开“调整填写位置”。未确认的新模板不会覆盖正在使用的模板，可随时放弃更换。
+模板窗口左侧显示 Excel 原表，右侧显示识别到的工作表、明细范围和收款位置。“查看 / 更换”、新导入确认页与报销单预览共用同一套表格渲染，不再使用系统 Quick Look；切换填写工作表时同步显示对应工作表。模板预览为独立只读操作，不需要勾选费用，不计算或回写原模板公式，加载失败可重试。核对后点击“确认位置，使用此模板”。仅在识别不正确时打开“调整填写位置”。未确认的新模板不会覆盖正在使用的模板，可随时放弃更换。
 
 模板只保存本机副本，重启后仍有效，不修改导入的原始文件。仅影响个人报销单，不影响 PPT、行程表及勾选范围；仍按所选费用类型合并金额、单据数，每类型一行。保留模板样式、合并区域、打印设置、其他工作表和未映射内容；明细超出确认范围时复制报销工作表分页。合计和其他公式在 Excel / WPS 打开后重新计算。
 
@@ -56,9 +56,9 @@ xcodebuild -project reimburse.xcodeproj -scheme reimburse \
 
 ### 导出前预览
 
-在“已核对”勾选材料 → “所选报销单” → 编辑用途、签字及收款资料 → “预览报销单”。应用先按当前模板生成实际 Excel，再从该文件读取列宽、行高、合并区域、文字和边框样式进行原生表格预览。默认适合宽度且不自动放大，可切换整页、100%、手动缩放及工作表，不单独挤压列宽。可返回修改，确认无误后点击“确认并保存”选择位置；保存的字节与预览文件一致，不重新生成另一份报销单。取消保存仍留在预览页面。
+在“已核对”勾选材料 → “所选报销单” → 编辑用途、签字及收款资料 → “预览报销单”。此处只显示已填写的报销单，不再提供原始模板切换。应用先按当前模板生成实际 Excel，再读取该文件的单元格内容与样式，以统一比例显示列宽、行高、合并区域、边框和文字；支持工作表选择、适合宽度、整页及手动缩放。右上角放大按钮打开可调整大小、可全屏的预览窗口，返回修改或关闭报销单时一并关闭。确认后保存的字节与预览源文件一致，不重新生成另一份报销单。取消保存仍留在预览页面。
 
-预览优先使用模板字体，未安装的字体使用本机同类字体替代。图片、图表、条件格式及部分特殊数字格式会提示在 Excel / WPS 中核对，不保证这些高级内容逐像素一致；模板导入窗口仍使用系统 Quick Look。
+跨单元格文字占用空白单元格时，按实际字宽隐藏被跨过的竖边框；保留其他边框，不擅自加线或改变模板合并关系。支持堆叠竖排、底部对齐及会计格式的右侧金额填充，合并区域使用外围边框。这些规则按实际工作表、单元格和样式读取，不绑定内置模板的具体地址。优先使用本机模板字体，缺失字体采用系统替代并明确提示；图片、图表、条件格式等高级效果会提示在办公软件核对，不承诺任意模板与 WPS 逐像素相同。预览限制不改变导出的模板样式。
 
 预览会刷新受支持公式的缓存（求和、同表引用、基本四则运算、条件判断、今日日期及内置人民币大写公式），保留公式本身。复杂自定义公式不猜测结果：移除旧缓存，明确列出尚未计算的单元格，由 Excel / WPS 打开后重算。预览属于屏幕表格展示，不是分页打印校样；打印设置保留在 Excel 中。
 
diff --git a/native-engine/engine.py b/native-engine/engine.py
index bf996ce..3393837 100644
--- a/native-engine/engine.py
+++ b/native-engine/engine.py
@@ -87,6 +87,9 @@ def dispatch(request):
         return scan(request)
     if operation == 'inspect-expense-template':
         return inspect_template(request['templatePath'])
+    if operation == 'preview-expense-template':
+        from spreadsheet_layout import read_layout
+        return read_layout(request['templatePath'])
     if operation == 'validate-expense-template':
         return validate_template(request['templatePath'], request['templateMapping'])
     state = request['state']
diff --git a/native-engine/expense_preview.py b/native-engine/expense_preview.py
index ad63719..ed53135 100644
--- a/native-engine/expense_preview.py
+++ b/native-engine/expense_preview.py
@@ -218,5 +218,6 @@ def prepare_preview(path):
     with zipfile.ZipFile(path, 'w', zipfile.ZIP_DEFLATED) as output:
         for name, data in template.parts.items():
             output.writestr(name, data)
-    return dict(expensePreview='xlsx-layout-v2', previewUncalculatedCells=uncalculated,
-                previewLayout=read_layout(path))
+    result = dict(expensePreview='xlsx-layout-v4', previewUncalculatedCells=uncalculated,
+                  previewLayout=read_layout(path))
+    return result
diff --git a/native-engine/spreadsheet_layout.py b/native-engine/spreadsheet_layout.py
index be908f5..22c9578 100644
--- a/native-engine/spreadsheet_layout.py
+++ b/native-engine/spreadsheet_layout.py
@@ -1,131 +1,128 @@
-"""Read-only display geometry from the exact XLSX that will be saved."""
-import datetime
+"""Read-only workbook display model; never modify the exported workbook."""
 import math
 import mimetypes
 import re
 from decimal import Decimal, ROUND_HALF_UP
 
-# Match the travel exporter: the app sandbox cannot read system MIME databases.
+# openpyxl otherwise reads system MIME files unavailable in the app sandbox.
 mimetypes.knownfiles = []
 mimetypes.init()
-
 from openpyxl.styles.colors import COLOR_INDEX
 from openpyxl.styles.numbers import BUILTIN_FORMATS, is_date_format
 from openpyxl.utils.datetime import from_excel, MAC_EPOCH, WINDOWS_EPOCH
 
 from expense_template import Template, column_name, coordinate, tag, xml
 
-DRAWING = 'http://schemas.openxmlformats.org/drawingml/2006/main'
 MAX_CELLS = 50000
+DRAWING = 'http://schemas.openxmlformats.org/drawingml/2006/main'
 
 
-def flag(node, name, default=False):
-    return node.get(name, '1' if default else '0') in ('1', 'true')
+def flag(node, key, default=False):
+    return node.get(key, '1' if default else '0') in ('1', 'true')
 
 
-def child_value(node, name, fallback):
+def child_value(node, name, default):
     child = node.find(tag(name))
-    return child.get('val', fallback) if child is not None else fallback
+    return child.get('val', default) if child is not None else default
 
 
 def theme_colors(template):
-    if 'xl/theme/theme1.xml' not in template.parts:
-        return ['FFFFFF', '000000', 'EEECE1', '1F497D', '4F81BD', 'C0504D',
+    defaults = ['FFFFFF', '000000', 'EEECE1', '1F497D', '4F81BD', 'C0504D',
                 '9BBB59', '8064A2', '4BACC6', 'F79646', '0000FF', '800080']
+    if 'xl/theme/theme1.xml' not in template.parts:
+        return defaults
     scheme = xml(template.parts['xl/theme/theme1.xml']).find('.//{' + DRAWING + '}clrScheme')
-    by_name = {entry.tag.split('}')[-1]: entry[0].get('lastClr', entry[0].get('val', '000000'))
-               for entry in scheme}
-    return [by_name.get(name, '000000') for name in
-            ['lt1', 'dk1', 'lt2', 'dk2', 'accent1', 'accent2', 'accent3', 'accent4',
-             'accent5', 'accent6', 'hlink', 'folHlink']]
+    if scheme is None:
+        return defaults
+    colors = {entry.tag.split('}')[-1]: entry[0].get('lastClr', entry[0].get('val', '000000'))
+              for entry in scheme if len(entry)}
+    return [colors.get(name, defaults[i]) for i, name in enumerate(
+        ['lt1', 'dk1', 'lt2', 'dk2', 'accent1', 'accent2', 'accent3', 'accent4',
+         'accent5', 'accent6', 'hlink', 'folHlink'])]
 
 
-def color(node, palette, fallback='000000'):
+def color(node, palette, default='000000'):
     if node is None:
-        return fallback
+        return default
     value = node.get('rgb')
     if value is None and 'theme' in node.attrib:
         value = palette[int(node.get('theme')) % len(palette)]
     if value is None and 'indexed' in node.attrib:
         index = int(node.get('indexed'))
-        value = COLOR_INDEX[index] if index < len(COLOR_INDEX) else fallback
-    value = (value or fallback)[-6:]
+        value = COLOR_INDEX[index] if 0 <= index < len(COLOR_INDEX) else default
+    value = (value or default)[-6:]
     if not re.fullmatch('[0-9a-fA-F]{6}', value):
-        return fallback
+        return default
     tint = max(-1, min(1, float(node.get('tint', 0))))
-    return ''.join(f'{round(channel * (1 + tint) if tint < 0 else channel * (1 - tint) + 255 * tint):02X}'
-                   for channel in (int(value[index:index + 2], 16) for index in (0, 2, 4)))
+    return ''.join(f'{round(c * (1 + tint) if tint < 0 else c * (1 - tint) + 255 * tint):02X}'
+                   for c in (int(value[i:i + 2], 16) for i in (0, 2, 4)))
 
 
 def literal(value):
     return re.sub(r'"([^"]*)"|\\(.)|_.|\*.', lambda m: m[1] or m[2] or '', value)
 
 
+def number_section(value, code):
+    sections = re.split(r';(?=(?:[^"]*"[^"]*")*[^"]*$)', code)
+    return (sections[2] if value == 0 and len(sections) > 2 else
+            sections[1] if value < 0 and len(sections) > 1 else sections[0])
+
+
 def formatted(value, kind, code, date_1904, warnings):
-    if value == '' or kind in ('s', 'inlineStr', 'str', 'e'):
+    if not value or kind in ('s', 'inlineStr', 'str', 'e'):
         return value
     if kind == 'b':
         return 'TRUE' if value == '1' else 'FALSE'
     number = Decimal(value)
     if is_date_format(code):
         date = from_excel(float(number), MAC_EPOCH if date_1904 else WINDOWS_EPOCH)
-        if isinstance(date, (datetime.datetime, datetime.time)):
-            # Excel date/time tokens are not strftime tokens (notably month/minute).
-            section = code.split(';')[0]
-            section = re.sub(r'\[[^\]]*\]', '', section)
-            section = literal(section)
-            if isinstance(date, datetime.datetime) and section.lower() == 'mm-dd-yy':
-                return date.strftime('%m-%d-%y')
-            if re.fullmatch(r'yyyy([/.-])m{1,2}\1d{1,2}', section, re.I):
-                sep = section[4]
-                return f'{date.year}{sep}{date.month:02d}{sep}{date.day:02d}' if 'mm' in section.lower() else f'{date.year}{sep}{date.month}{sep}{date.day}'
-            if section.lower() in ('yyyy"年"m"月"d"日"', 'yyyy年m月d日'):
-                return f'{date.year}年{date.month}月{date.day}日'
-            if section.lower() in ('h:mm', 'hh:mm', 'h:mm:ss', 'hh:mm:ss'):
-                return date.strftime('%H:%M:%S' if 'ss' in section.lower() else '%H:%M')
-            warnings.add('部分日期格式使用标准日期显示')
-            return date.date().isoformat() if isinstance(date, datetime.datetime) else date.isoformat()
+        section = literal(re.sub(r'\[[^\]]*\]', '', code.split(';')[0])).lower()
+        if section == 'mm-dd-yy':
+            return date.strftime('%m/%d/%y')
+        if re.fullmatch(r'yyyy([/.-])m{1,2}\1d{1,2}', section):
+            return (str(date.year) + section[4] + (f'{date.month:02d}' if 'mm' in section else str(date.month))
+                    + section[4] + (f'{date.day:02d}' if 'dd' in section else str(date.day)))
+        if section == 'yyyy年m月d日':
+            return f'{date.year}年{date.month}月{date.day}日'
+        if section in ('h:mm', 'hh:mm', 'h:mm:ss', 'hh:mm:ss'):
+            return date.strftime('%H:%M:%S' if 'ss' in section else '%H:%M')
+        warnings.add('特殊日期格式请在办公软件中核对')
+        return date.date().isoformat() if hasattr(date, 'date') else date.isoformat()
     if code.lower() in ('general', '@'):
         return format(number, 'f').rstrip('0').rstrip('.') if '.' in str(number) else str(number)
-    sections = re.split(r';(?=(?:[^"]*"[^"]*")*[^"]*$)', code)
-    section = sections[2] if number == 0 and len(sections) > 2 else sections[1] if number < 0 and len(sections) > 1 else sections[0]
+    section = number_section(number, code)
     section = re.sub(r'\[\$([^\]-]*)[^\]]*\]', lambda m: m[1], section)
     if re.search(r'\[(?:[<>=]|\d)', section):
-        warnings.add('部分条件数字格式使用原始数值显示')
+        warnings.add('条件数字格式请在办公软件中核对')
         return str(number)
     section = re.sub(r'\[[^\]]*\]', '', section)
-    # Ignore placeholders inside quoted/escaped literals.
     masked = re.sub(r'"[^"]*"|\\.|_.|\*.', lambda m: ' ' * len(m[0]), section)
     match = re.search(r'[#0][#0,]*(?:\.[#0?]+)?%?', masked)
     if not match:
         return literal(section).strip().replace('?', '')
     if re.search(r'[Ee][+-]|[/]', masked) or masked[match.end():].lstrip().startswith(','):
-        warnings.add('部分科学计数或分数格式使用原始数值显示')
+        warnings.add('特殊数字格式请在办公软件中核对')
         return str(number)
     pattern = match[0]
-    places = len(pattern.rstrip('%').split('.')[1]) if '.' in pattern else 0
-    value = abs(number) if number < 0 and len(sections) > 1 else number
+    fraction = pattern.rstrip('%').split('.')[1] if '.' in pattern else ''
+    number = abs(number) if number < 0 and len(code.split(';')) > 1 else number
     if '%' in pattern:
-        value *= 100
-    value = value.quantize(Decimal(1).scaleb(-places), rounding=ROUND_HALF_UP)
-    text = format(value, (',' if ',' in pattern else '') + f'.{places}f')
-    if '.' in pattern:
-        fraction = pattern.rstrip('%').split('.')[1]
-        optional = len(fraction) - len(fraction.rstrip('#?'))
-        for _ in range(optional):
-            if text.endswith('0'):
-                text = text[:-1]
+        number *= 100
+    number = number.quantize(Decimal(1).scaleb(-len(fraction)), rounding=ROUND_HALF_UP)
+    text = format(number, (',' if ',' in pattern else '') + f'.{len(fraction)}f')
+    for _ in range(len(fraction) - len(fraction.rstrip('#?'))):
+        if text.endswith('0'):
+            text = text[:-1]
+    if fraction:
         text = text.rstrip('.')
     if ',' not in pattern and '.' not in pattern:
         text = text.zfill(pattern.count('0'))
-    if '%' in pattern:
-        text += '%'
-    return literal(section[:match.start()]) + text + literal(section[match.end():])
+    return literal(section[:match.start()]) + text + ('%' if '%' in pattern else '') + literal(section[match.end():])
 
 
 def read_styles(template, palette):
     root = xml(template.parts['xl/styles.xml'])
-    fonts, fills, borders = root.find(tag('fonts')), root.find(tag('fills')), root.find(tag('borders'))
+    fonts, fills, borders = (root.find(tag(name)) for name in ('fonts', 'fills', 'borders'))
     formats = dict(BUILTIN_FORMATS)
     for item in root.findall(tag('numFmts') + '/' + tag('numFmt')):
         formats[int(item.get('numFmtId'))] = item.get('formatCode')
@@ -153,93 +150,89 @@ def read_styles(template, palette):
             horizontal=alignment.get('horizontal', 'general'), vertical=alignment.get('vertical', 'bottom'),
             wrap=alignment.get('wrapText') in ('1', 'true'), shrink=alignment.get('shrinkToFit') in ('1', 'true'),
             rotation=int(alignment.get('textRotation', 0)), indent=float(alignment.get('indent', 0)),
-            borders=sides, numberFormat=formats.get(int(entry.get('numFmtId', 0)), 'General')
-        ))
+            borders=sides, numberFormat=formats.get(int(entry.get('numFmtId', 0)), 'General'),
+            accounting=False))
     return styles
 
 
 def read_layout(path):
     template = Template(path)
-    palette = theme_colors(template)
-    styles = read_styles(template, palette)
+    styles = read_styles(template, theme_colors(template))
     properties = template.workbook.find(tag('workbookPr'))
     date_1904 = properties is not None and flag(properties, 'date1904')
-    warnings = set()
-    sheets, total_cells = [], 0
+    sheets, warnings, total_cells = [], set(), 0
     for sheet_index, sheet in enumerate(template.sheets):
         if sheet.get('state', 'visible') != 'visible':
             continue
         name = sheet.get('name')
         _, _, document = template.sheet(name)
-        cells = {cell.get('r'): cell for cell in document.iter(tag('c'))}
-        merges = [item.get('ref') for item in document.iter(tag('mergeCell'))]
-        # Empty formatted tail columns must not squeeze the actual form. Preserve
-        # all nonempty cells, even when they are outside the workbook print area.
-        references = [ref for ref, cell in cells.items() if cell.find(tag('v')) is not None or
-                      cell.find(tag('is')) is not None or cell.find(tag('f')) is not None]
-        ranges = []
+        cells = {c.get('r'): c for c in document.iter(tag('c'))}
+        merges = [m.get('ref') for m in document.iter(tag('mergeCell'))]
+        references = [ref for ref, c in cells.items() if any(c.find(tag(k)) is not None for k in ('v', 'is', 'f'))]
         for definition in template.workbook.findall(tag('definedNames') + '/' + tag('definedName')):
             if definition.get('name') == '_xlnm.Print_Area' and definition.get('localSheetId') == str(sheet_index):
-                ranges += re.findall(r'\$?([A-Z]+)\$?(\d+):\$?([A-Z]+)\$?(\d+)', definition.text or '')
-        references += [f'{c}{r}' for a, b, c, r in ranges]
-        references += [entry.split(':')[-1] for entry in merges]
-        if not references:
-            references = list(cells) or ['A1']
-        positions = [coordinate(ref) for ref in references]
+                references += [c + r for _, _, c, r in re.findall(
+                    r'\$?([A-Z]+)\$?(\d+):\$?([A-Z]+)\$?(\d+)', definition.text or '')]
+        references += [m.split(':')[-1] for m in merges]
+        positions = [coordinate(ref) for ref in references or list(cells) or ['A1']]
         columns, rows = max(p[0] for p in positions), max(p[1] for p in positions)
-        if columns * rows > MAX_CELLS or total_cells + len(cells) > MAX_CELLS:
+        total_cells += columns * rows
+        if total_cells > MAX_CELLS:
             raise ValueError('模板范围过大，无法完整预览；请精简模板后重试')
-        total_cells += len(cells)
         defaults = document.find(tag('sheetFormatPr'))
-        default_width = float(defaults.get('defaultColWidth', 8.43)) if defaults is not None else 8.43
-        default_height = float(defaults.get('defaultRowHeight', 15)) if defaults is not None else 15
-        widths = [default_width] * columns
-        heights = [default_height] * rows
+        dw = float(defaults.get('defaultColWidth', 8.43)) if defaults is not None else 8.43
+        dh = float(defaults.get('defaultRowHeight', 15)) if defaults is not None else 15
+        widths, heights = [dw] * columns, [dh] * rows
+        column_styles, row_styles = {}, {}
         for column in document.findall(tag('cols') + '/' + tag('col')):
-            for index in range(int(column.get('min')) - 1, min(columns, int(column.get('max')))):
-                widths[index] = 0 if flag(column, 'hidden') else float(column.get('width', default_width))
+            for index in range(max(0, int(column.get('min')) - 1), min(columns, int(column.get('max')))):
+                widths[index] = 0 if flag(column, 'hidden') else float(column.get('width', dw))
+                column_styles[index + 1] = int(column.get('style', 0))
         for row in document.findall(tag('sheetData') + '/' + tag('row')):
             index = int(row.get('r')) - 1
-            if index < rows:
-                heights[index] = 0 if flag(row, 'hidden') else float(row.get('ht', default_height))
-        # OOXML width is expressed in maximum-digit units. Geometry is kept at
-        # 96 dpi; Swift scales the complete sheet, never individual columns.
-        widths = [math.floor(((256 * width + 18) / 256) * 7) for width in widths]
-        heights = [height * 4 / 3 for height in heights]
+            if 0 <= index < rows:
+                heights[index] = 0 if flag(row, 'hidden') else float(row.get('ht', dh))
+                if flag(row, 'customFormat'):
+                    row_styles[index + 1] = int(row.get('s', 0))
         xs, ys = [0], [0]
         for width in widths:
-            xs.append(xs[-1] + width)
+            xs.append(xs[-1] + math.floor(((256 * width + 18) / 256) * 7))
         for height in heights:
-            ys.append(ys[-1] + height)
+            ys.append(ys[-1] + height * 4 / 3)
         covered, spans = set(), {}
         for merged in merges:
             first, last = merged.split(':')
             left, top = coordinate(first)
             right, bottom = coordinate(last)
             spans[first] = (right, bottom)
-            covered.update((col, row) for col in range(left, right + 1) for row in range(top, bottom + 1)
-                           if (col, row) != (left, top))
-        output = []
-        occupied = {coordinate(ref) for ref, cell in cells.items()
-                    if cell.find(tag('v')) is not None or cell.find(tag('is')) is not None
-                    or cell.find(tag('f')) is not None}
+            covered.update((c, r) for c in range(left, right + 1) for r in range(top, bottom + 1)
+                           if (c, r) != (left, top))
+
+        def style_at(ref):
+            col, row = coordinate(ref)
+            cell = cells.get(ref)
+            return styles[int(cell.get('s', row_styles.get(row, column_styles.get(col, 0)))) if cell is not None
+                          else row_styles.get(row, column_styles.get(col, 0))]
+
+        occupied = {coordinate(ref) for ref, c in cells.items()
+                    if any(c.find(tag(k)) is not None for k in ('v', 'is', 'f'))}
         occupied.update(covered)
         occupied.update(coordinate(ref) for ref in spans)
+        output = []
         for reference, cell in cells.items():
             col, row = coordinate(reference)
             if col > columns or row > rows or (col, row) in covered:
                 continue
             right, bottom = spans.get(reference, (col, row))
-            style = int(cell.get('s', 0))
-            appearance = dict(styles[style])
+            appearance = dict(style_at(reference))
             appearance['borders'] = dict(appearance['borders'])
-            # Merged right/bottom edges may be stored on the last cell.
-            for edge, edge_ref in [('right', column_name(right) + str(row)),
-                                   ('bottom', column_name(col) + str(bottom)),
-                                   ('right', column_name(right) + str(bottom)),
-                                   ('bottom', column_name(right) + str(bottom))]:
-                if edge not in appearance['borders'] and edge_ref in cells:
-                    candidate = styles[int(cells[edge_ref].get('s', 0))]['borders'].get(edge)
+            if reference in spans:
+                # Use the perimeter, not the anchor's former internal edges.
+                for edge, edge_ref in [('right', column_name(right) + str(row)),
+                                       ('bottom', column_name(col) + str(bottom)),
+                                       ('right', column_name(right) + str(bottom)),
+                                       ('bottom', column_name(right) + str(bottom))]:
+                    candidate = style_at(edge_ref)['borders'].get(edge)
                     if candidate:
                         appearance['borders'][edge] = candidate
             kind = cell.get('t', 'n')
@@ -247,26 +240,33 @@ def read_layout(path):
             if kind == 's':
                 value = template.shared[int(value)] if value else ''
             elif kind == 'inlineStr':
-                value = ''.join(node.text or '' for node in cell.iter(tag('t')))
+                value = ''.join(t.text or '' for t in cell.iter(tag('t')))
             text = formatted(value, kind, appearance['numberFormat'], date_1904, warnings)
+            if kind == 'n' and value:
+                section = number_section(Decimal(value), appearance['numberFormat'])
+                # Asterisk-space pads the value to the right even when the cell
+                # alignment is centered. Do not discard that layout instruction.
+                masked = re.sub(r'"[^"]*"|\\.', '', section)
+                appearance['accounting'] = '* ' in masked
             if appearance['horizontal'] == 'general':
                 appearance['horizontal'] = 'right' if kind == 'n' else 'center' if kind == 'b' else 'left'
             width, height = xs[right] - xs[col - 1], ys[bottom] - ys[row - 1]
-            if width > 0 and height > 0:
-                left_limit, right_limit = col, right
-                if (text and kind in ('s', 'inlineStr', 'str') and reference not in spans
-                        and not appearance['wrap'] and not appearance['shrink'] and appearance['rotation'] == 0):
-                    if appearance['horizontal'] in ('left', 'center'):
-                        while right_limit < columns and (right_limit + 1, row) not in occupied:
-                            right_limit += 1
-                    if appearance['horizontal'] in ('right', 'center'):
-                        while left_limit > 1 and (left_limit - 1, row) not in occupied:
-                            left_limit -= 1
-                output.append(dict(reference=reference, x=xs[col - 1], y=ys[row - 1], width=width, height=height,
-                                   text=text, style=appearance,
-                                   overflowLeft=xs[left_limit - 1], overflowRight=xs[right_limit]))
+            if width <= 0 or height <= 0:
+                continue
+            left_limit, right_limit = col, right
+            if (text and kind in ('s', 'inlineStr', 'str') and reference not in spans
+                    and not appearance['wrap'] and not appearance['shrink'] and appearance['rotation'] == 0):
+                if appearance['horizontal'] in ('left', 'center'):
+                    while right_limit < columns and (right_limit + 1, row) not in occupied:
+                        right_limit += 1
+                if appearance['horizontal'] in ('right', 'center'):
+                    while left_limit > 1 and (left_limit - 1, row) not in occupied:
+                        left_limit -= 1
+            output.append(dict(reference=reference, x=xs[col - 1], y=ys[row - 1], width=width, height=height,
+                               text=text, style=appearance, overflowLeft=xs[left_limit - 1],
+                               overflowRight=xs[right_limit]))
         for feature in ('drawing', 'legacyDrawing', 'conditionalFormatting'):
             if document.find(tag(feature)) is not None:
                 warnings.add('模板中的图片、图表或条件格式请在 Excel / WPS 中核对')
         sheets.append(dict(name=name, width=max(1, xs[-1]), height=max(1, ys[-1]), cells=output))
-    return dict(version=1, sheets=sheets, warnings=sorted(warnings))
+    return dict(version=4, sheets=sheets, warnings=sorted(warnings))
diff --git a/native-engine/tests/test_expense_preview.py b/native-engine/tests/test_expense_preview.py
index d6b9615..d751fa5 100644
--- a/native-engine/tests/test_expense_preview.py
+++ b/native-engine/tests/test_expense_preview.py
@@ -12,7 +12,7 @@ from openpyxl import load_workbook
 sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
 import test_expense_template as fixtures
 from expense_preview import PreviewCalculator, UnsupportedFormula, builtin_rmb, prepare_preview
-from expense_template import Template, encoded, set_cell, tag
+from expense_template import Template, encoded, export_custom_expense, set_cell, tag
 
 
 class ExpensePreviewTests(unittest.TestCase):
@@ -36,10 +36,48 @@ class ExpensePreviewTests(unittest.TestCase):
         self.assertEqual(formulas.active['H29'].value, '=IF(F27>C27,F27-C27,0)')
         self.assertEqual(result['previewUncalculatedCells'], [])
         self.assertEqual(sheet['D29'].value, '伍佰肆拾肆元叁角整')
-        self.assertEqual(result['expensePreview'], 'xlsx-layout-v2')
+        self.assertEqual(result['expensePreview'], 'xlsx-layout-v4')
         values.close()
         formulas.close()
 
+    def test_original_preview_preserves_signature_borders_fonts_and_geometry(self):
+        signatures = ['部门长', '剧组出纳', '制片主任', '剧组会计', '执行制片人']
+        payee = dict(recipient='测试收款人', bankName='测试银行', accountNumber='001234567890')
+        source = self.fixture.root / 'signature-template.xlsx'
+        output = self.fixture.root / 'signature-preview.xlsx'
+        export_custom_expense(self.fixture.state, source, self.fixture.template, self.fixture.mapping,
+                              {}, signatures, payee, {})
+        prepare_preview(source)
+        changed = dict(matches=[self.fixture.match('preview-changed', '交通', '447')])
+        export_custom_expense(changed, output, source, self.fixture.mapping,
+                              {}, signatures, payee, {})
+        result = prepare_preview(output)
+        original, preview = Template(source), Template(output)
+        self.assertEqual(result['previewLayout']['version'], 4)
+        self.assertEqual(original.parts['xl/styles.xml'], preview.parts['xl/styles.xml'])
+        _, _, before = original.sheet('个人报销单')
+        _, _, after = preview.sheet('个人报销单')
+        for name in ['cols', 'mergeCells', 'sheetFormatPr', 'pageMargins', 'pageSetup']:
+            self.assertEqual(encoded(before.find(tag(name))), encoded(after.find(tag(name))), name)
+        for reference, label in zip(['A30', 'D30', 'A31', 'D31', 'A32'], signatures):
+            old = before.find('.//' + tag('c') + f'[@r="{reference}"]')
+            new = after.find('.//' + tag('c') + f'[@r="{reference}"]')
+            self.assertEqual(encoded(old), encoded(new), reference)
+            self.assertEqual(''.join(node.text or '' for node in new.iter(tag('t'))), label + '：')
+        old_cells = {cell.get('r'): cell.get('s') for cell in before.iter(tag('c'))}
+        new_cells = {cell.get('r'): cell.get('s') for cell in after.iter(tag('c'))}
+        self.assertEqual(old_cells, new_cells)
+        for row in [30, 31, 32]:
+            old = before.find(tag('sheetData') + '/' + tag('row') + f'[@r="{row}"]')
+            new = after.find(tag('sheetData') + '/' + tag('row') + f'[@r="{row}"]')
+            self.assertEqual(old.attrib, new.attrib)
+        folder = os.environ.get('RECEIPT_PREVIEW_FIXTURE_DIR')
+        if folder:
+            folder = Path(folder)
+            folder.mkdir(parents=True, exist_ok=True)
+            (folder / 'template.xlsx').write_bytes(source.read_bytes())
+            (folder / 'preview.xlsx').write_bytes(output.read_bytes())
+
     def test_builtin_uppercase_amount_formula(self):
         for amount, expected in [('3491.86', '叁仟肆佰玖拾壹元捌角陆分'), ('10001.01', '壹万零壹元零壹分'),
                                  ('100000001', '壹亿零壹元整'), ('100010000', '壹亿零壹万元整'),
@@ -105,8 +143,9 @@ class ExpensePreviewTests(unittest.TestCase):
                 process = subprocess.run(command, input=json.dumps(request) + '\n', text=True, capture_output=True, timeout=60)
                 self.assertEqual(process.returncode, 0, process.stderr + process.stdout)
                 result = next(json.loads(line)['result'] for line in process.stdout.splitlines() if json.loads(line).get('event') == 'result')
-                self.assertEqual(result['expensePreview'], 'xlsx-layout-v2')
+                self.assertEqual(result['expensePreview'], 'xlsx-layout-v4')
                 self.assertTrue(result['previewLayout']['sheets'])
+                self.assertNotIn('templatePreviewLayout', result)
                 self.assertEqual(result['expenseRowCount'], 2)
                 workbook = load_workbook(output, data_only=True)
                 self.assertEqual(workbook.active['F27'].value, 544.3)
@@ -114,6 +153,22 @@ class ExpensePreviewTests(unittest.TestCase):
                 self.assertIn(workbook.active['C23'].value, ('', None))
                 workbook.close()
 
+    def test_engine_process_template_preview_is_read_only_without_expense_selection(self):
+        from spreadsheet_layout import read_layout
+        alternate, _ = self.fixture.alternate()
+        binary = os.environ.get('RECEIPT_ENGINE_BINARY')
+        command = [binary] if binary else [sys.executable, str(Path(__file__).resolve().parents[1] / 'engine.py')]
+        for source in [self.fixture.template, alternate]:
+            before = source.read_bytes()
+            request = dict(operation='preview-expense-template', templatePath=str(source))
+            process = subprocess.run(command, input=json.dumps(request) + '\n', text=True,
+                                     capture_output=True, timeout=60)
+            self.assertEqual(process.returncode, 0, process.stderr + process.stdout)
+            result = next(json.loads(line)['result'] for line in process.stdout.splitlines()
+                          if json.loads(line).get('event') == 'result')
+            self.assertEqual(result, read_layout(source))
+            self.assertEqual(source.read_bytes(), before)
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/native-engine/tests/test_spreadsheet_layout.py b/native-engine/tests/test_spreadsheet_layout.py
index f82a569..47b4190 100644
--- a/native-engine/tests/test_spreadsheet_layout.py
+++ b/native-engine/tests/test_spreadsheet_layout.py
@@ -1,16 +1,15 @@
 import json
 import os
 from pathlib import Path
-import sys
 import subprocess
+import sys
 import unittest
 
 from lxml import etree as ET
-
 sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
 import test_expense_template as fixtures
+from expense_template import Template, encoded, export_custom_expense, inspect_template, set_cell, tag
 from expense_preview import prepare_preview
-from expense_template import Template, encoded, tag
 from spreadsheet_layout import formatted, read_layout
 
 
@@ -20,93 +19,143 @@ class SpreadsheetLayoutTests(unittest.TestCase):
         self.fixture.setUp()
         self.addCleanup(self.fixture.tearDown)
 
-    def test_fresh_import_does_not_read_system_mime_database(self):
-        code = """
-import sys
-def audit(event, args):
-    if event == 'open' and str(args[0]).endswith('mime.types'):
-        raise PermissionError('System MIME database is unavailable in the app sandbox')
-sys.addaudithook(audit)
-import spreadsheet_layout
-"""
-        result = subprocess.run([sys.executable, '-c', code],
-                                cwd=Path(__file__).resolve().parents[1], capture_output=True, text=True)
-        self.assertEqual(result.returncode, 0, result.stderr)
-
-    def test_actual_workbook_geometry_styles_and_values(self):
-        output, _ = self.fixture.export(payee=dict(recipient='测试收款人', bankName='测试银行测试支行',
-                                                   accountNumber='001234567890'))
+    def test_wps_signature_and_accounting_regressions(self):
+        source = Path(os.environ.get('RECEIPT_PREVIEW_SOURCE', self.fixture.template))
+        original = source.read_bytes()
+        mapping = inspect_template(source)['sheets'][0]['mapping']
+        output = self.fixture.root / 'preview.xlsx'
+        export_custom_expense(dict(matches=[self.fixture.match('changed', '交通', '447')]),
+                              output, source, mapping, {},
+                              ['部门长', '剧组出纳', '制片主任', '剧组会计', '执行制片人'],
+                              dict(recipient='测试收款人', bankName='测试银行', accountNumber='001234567890'), {})
         result = prepare_preview(output)
         before = output.read_bytes()
         layout = read_layout(output)
-        self.assertEqual(before, output.read_bytes())
+        self.assertEqual(output.read_bytes(), before)
+        self.assertEqual(source.read_bytes(), original)
         self.assertEqual(layout, result['previewLayout'])
-        sheet = layout['sheets'][0]
-        cells = {cell['reference']: cell for cell in sheet['cells']}
-        self.assertEqual(cells['C23']['text'], '测试收款人')
-        self.assertEqual(cells['C25']['text'], '001234567890')
-        self.assertEqual(cells['F27']['text'].strip(), '544.30')
-        self.assertEqual(cells['D29']['text'], '伍佰肆拾肆元叁角整')
-        self.assertNotIn('D23', cells)
-        self.assertAlmostEqual(cells['C23']['x'] + cells['C23']['width'], sheet['width'])
+        self.assertNotIn('templatePreviewLayout', result)
+        cells = {c['reference']: c for c in layout['sheets'][0]['cells']}
+        for ref, label in [('A30', '部门长'), ('D30', '剧组出纳'), ('A31', '制片主任'), ('D31', '剧组会计')]:
+            self.assertEqual(cells[ref]['text'], label + '：')
+            self.assertGreater(cells[ref]['overflowRight'], cells[ref]['x'] + cells[ref]['width'])
+        self.assertEqual(cells['A30']['overflowRight'], cells['D30']['x'])
         self.assertEqual(cells['H30']['style']['rotation'], 255)
-        self.assertGreater(cells['A30']['overflowRight'], cells['A30']['x'] + cells['A30']['width'])
-        self.assertLessEqual(cells['A30']['overflowRight'], cells['D30']['x'])
-        _, _, document = Template(output).sheet(sheet['name'])
-        row = document.find(tag('sheetData') + '/' + tag('row') + '[@r="30"]')
-        self.assertAlmostEqual(cells['A30']['height'], float(row.get('ht')) * 4 / 3)
-        self.assertAlmostEqual(cells['H30']['height'], sum(cells[ref]['height'] for ref in ['A30', 'A31', 'A32']))
-        self.assertEqual(cells['F27']['style']['horizontal'], 'center')
-        self.assertEqual(cells['F27']['style']['font'], 'SimSun-ExtB')
-        self.assertEqual(cells['C23']['style']['borders']['right']['style'], 'medium')
-        self.assertLess(sheet['width'], 1200)
-        self.assertGreater(sheet['height'], 1200)
+        self.assertEqual(cells['H30']['style']['vertical'], 'bottom')
+        self.assertEqual(cells['H30']['style']['borders']['right']['style'], 'medium')
+        self.assertEqual(cells['H30']['style']['borders']['bottom']['style'], 'medium')
+        for ref in ['F27', 'H29']:
+            self.assertTrue(cells[ref]['style']['accounting'])
+            self.assertEqual(cells[ref]['text'].strip(), '447.00')
+            self.assertTrue(cells[ref]['style']['bold'])
+        self.assertNotIn('left', cells['D31']['style']['borders'])
+        self.assertEqual(cells['C25']['text'], '001234567890')
         if os.environ.get('RECEIPT_PREVIEW_FIXTURE_DIR'):
             folder = Path(os.environ['RECEIPT_PREVIEW_FIXTURE_DIR'])
             folder.mkdir(parents=True, exist_ok=True)
             (folder / 'layout.json').write_text(json.dumps(layout, ensure_ascii=False), encoding='utf-8')
             (folder / 'preview.xlsx').write_bytes(before)
 
-    def test_all_visible_sheets_and_pagination_remain_available(self):
-        template, mapping = self.fixture.alternate()
-        state = dict(matches=self.fixture.state['matches'] + [self.fixture.match('third', '住宿', '50')])
-        output, _ = self.fixture.export(mapping=mapping, template=template, state=state)
-        layout = prepare_preview(output)['previewLayout']
-        self.assertEqual([sheet['name'] for sheet in layout['sheets']], ['组 B 报销', '保留说明', '组 B 报销-续2'])
-        notes = layout['sheets'][1]
-        self.assertEqual(notes['cells'][0]['text'], '保持这个工作表不变')
-        self.assertTrue(all(sheet['width'] > 0 and sheet['height'] > 0 for sheet in layout['sheets']))
+    def test_overflow_stops_at_text_and_merged_cells(self):
+        output, _ = self.fixture.export()
+        template = Template(output)
+        _, path, document = template.sheet('个人报销单')
+        set_cell(document, 'B30', '阻止覆盖')
+        template.parts[path] = encoded(document)
+        self.fixture.rewrite(output, template.parts)
+        cells = {c['reference']: c for c in read_layout(output)['sheets'][0]['cells']}
+        self.assertEqual(cells['A30']['overflowRight'], cells['A30']['x'] + cells['A30']['width'])
+        self.assertEqual(cells['D30']['overflowRight'], cells['H30']['x'])
+        self.assertEqual(cells['A32']['overflowRight'], cells['A32']['x'] + cells['A32']['width'])
 
-    def test_hidden_rows_columns_and_cells_outside_print_area(self):
+    def test_visible_sheets_and_pagination(self):
+        source, mapping = self.fixture.alternate()
+        state = dict(matches=self.fixture.state['matches'] + [self.fixture.match('extra', '住宿', '50')])
+        output, _ = self.fixture.export(mapping=mapping, template=source, state=state)
+        layout = prepare_preview(output)['previewLayout']
+        self.assertEqual([s['name'] for s in layout['sheets']], ['组 B 报销', '保留说明', '组 B 报销-续2'])
+
+    def test_unrelated_template_style_and_geometry(self):
+        from openpyxl import Workbook
+        from openpyxl.styles import Alignment, Border, Font, PatternFill, Side
+        workbook = Workbook()
+        sheet = workbook.active
+        sheet.title = '横向费用单'
+        sheet.column_dimensions['A'].width = 4
+        sheet.column_dimensions['B'].width = 24
+        sheet.column_dimensions['C'].width = 12
+        sheet.column_dimensions['D'].width = 20
+        sheet.column_dimensions['E'].width = 16
+        sheet.column_dimensions['F'].width = 10
+        sheet.row_dimensions[2].height = 42
+        sheet.row_dimensions[6].height = 34
+        sheet.merge_cells('B2:F2')
+        sheet['B2'] = '另一种费用模板'
+        sheet['B2'].font = Font(name='Arial', size=18, bold=True, color='145A32')
+        sheet['B2'].fill = PatternFill('solid', fgColor='D5F5E3')
+        sheet['B2'].alignment = Alignment(horizontal='center', vertical='center')
+        sheet['B2'].border = Border(bottom=Side(style='double', color='145A32'))
+        for ref, text in [('B5', '说明'), ('D5', '金额'), ('E5', '比例'), ('F5', '编号')]:
+            sheet[ref] = text
+        sheet.merge_cells('B6:C6')
+        sheet['B6'] = '这里是长一些的费用说明，需要按模板换行'
+        sheet['B6'].alignment = Alignment(wrap_text=True, vertical='top')
+        sheet['D6'] = 1234.5
+        sheet['D6'].number_format = '#,##0.00'
+        sheet['D6'].alignment = Alignment(horizontal='right')
+        sheet['E6'] = .125
+        sheet['E6'].number_format = '0.0%'
+        sheet['F6'] = '000012'
+        sheet.print_area = 'A1:F8'
+        workbook.create_sheet('说明页')['A1'] = '附加工作表'
+        output = self.fixture.root / 'different-style.xlsx'
+        workbook.save(output)
+        before = output.read_bytes()
+        layout = read_layout(output)
+        self.assertEqual(output.read_bytes(), before)
+        self.assertEqual([s['name'] for s in layout['sheets']], ['横向费用单', '说明页'])
+        cells = {c['reference']: c for c in layout['sheets'][0]['cells']}
+        self.assertNotIn('C2', cells)
+        self.assertNotIn('C6', cells)
+        self.assertEqual(cells['B2']['height'], 56)
+        self.assertEqual(cells['B2']['style']['font'], 'Arial')
+        self.assertEqual(cells['B2']['style']['fill'], 'D5F5E3')
+        self.assertEqual(cells['B2']['style']['borders']['bottom']['style'], 'double')
+        self.assertTrue(cells['B6']['style']['wrap'])
+        self.assertEqual(cells['D6']['text'], '1,234.50')
+        self.assertEqual(cells['D6']['style']['horizontal'], 'right')
+        self.assertEqual(cells['E6']['text'], '12.5%')
+        self.assertEqual(cells['F6']['text'], '000012')
+        if os.environ.get('RECEIPT_PREVIEW_FIXTURE_DIR'):
+            folder = Path(os.environ['RECEIPT_PREVIEW_FIXTURE_DIR'])
+            folder.mkdir(parents=True, exist_ok=True)
+            (folder / 'alternate-layout.json').write_text(json.dumps(layout, ensure_ascii=False), encoding='utf-8')
+
+    def test_hidden_dimensions_and_outside_print_area(self):
         output, _ = self.fixture.export()
         template = Template(output)
         _, path, document = template.sheet('个人报销单')
         document.find(tag('cols'))[0].set('hidden', '1')
-        row = document.find(tag('sheetData'))[0]
-        row.set('hidden', '1')
-        from expense_template import set_cell
-        set_cell(document, 'J36', '不能遗漏打印区域以外的内容')
+        document.find(tag('sheetData'))[0].set('hidden', '1')
+        set_cell(document, 'J36', '打印范围外')
         template.parts[path] = encoded(document)
         self.fixture.rewrite(output, template.parts)
-        sheet = read_layout(output)['sheets'][0]
-        cells = {cell['reference']: cell for cell in sheet['cells']}
+        cells = {c['reference']: c for c in read_layout(output)['sheets'][0]['cells']}
         self.assertNotIn('A9', cells)
-        self.assertNotIn('A1', cells)
         self.assertEqual(cells['B9']['x'], 0)
         self.assertIn('J36', cells)
 
-    def test_oversized_range_fails_instead_of_truncating(self):
+    def test_large_range_rejected(self):
         output, _ = self.fixture.export()
         template = Template(output)
         _, path, document = template.sheet('个人报销单')
-        from expense_template import set_cell
-        set_cell(document, 'IV2000', 'too large')
+        set_cell(document, 'IV2000', 'range')
         template.parts[path] = encoded(document)
         self.fixture.rewrite(output, template.parts)
         with self.assertRaisesRegex(ValueError, '范围过大'):
             read_layout(output)
 
-    def test_drawings_and_conditional_formatting_have_explicit_warning(self):
+    def test_advanced_features_warn(self):
         output, _ = self.fixture.export()
         template = Template(output)
         _, path, document = template.sheet('个人报销单')
@@ -115,29 +164,29 @@ import spreadsheet_layout
         self.fixture.rewrite(output, template.parts)
         self.assertTrue(read_layout(output)['warnings'])
 
-    def test_number_formats_and_text_identity(self):
+    def test_numeric_and_date_formatting(self):
         warnings = set()
-        for value, kind, code, expected in [
-            ('2122.60', 'n', '#,##0.00', '2,122.60'),
-            ('662.8', 'n', '0.00_ ', '662.80'),
-            ('0', 'n', '#,##0.00;(#,##0.00);"-"', '-'),
-            ('-25.3', 'n', '#,##0.00;(#,##0.00)', '(25.30)'),
-            ('0.125', 'n', '0.0%', '12.5%'),
-            ('8', 'n', '0000', '0008'),
-            ('80', 'n', '"¥"#,##0.00', '¥80.00'),
-            ('001234567890123456789', 'inlineStr', 'General', '001234567890123456789'),
-            ('=NotAFormula', 'inlineStr', 'General', '=NotAFormula'),
-            ('1', 'b', 'General', 'TRUE'),
-            ('12.50', 'n', 'General', '12.5'),
-            ('12.50', 'n', '0.##', '12.5'),
-            ('12', 'n', '0.0#', '12.0'),
-            ('1', 'n', 'mm-dd-yy', '01-01-00'),
-        ]:
-            with self.subTest(value=value, code=code):
-                self.assertEqual(formatted(value, kind, code, False, warnings), expected)
+        for value, code, expected in [('447', '_(* #,##0.00_);_(* (#,##0.00);_(* "-"??_);_(@_)', '447.00'),
+                                      ('2122.6', '#,##0.00', '2,122.60'), ('-25.3', '0.00;(0.00)', '(25.30)'),
+                                      ('12.50', '0.##', '12.5'), ('12', '0.0#', '12.0'),
+                                      ('8', '0000', '0008'), ('0.125', '0.0%', '12.5%')]:
+            self.assertEqual(formatted(value, 'n', code, False, warnings).strip(), expected)
         self.assertEqual(formatted('1', 'n', 'yyyy/m/d', True, warnings), '1904/1/2')
         self.assertFalse(warnings)
 
+    def test_sandbox_import(self):
+        script = """
+import sys
+def audit(event, args):
+    if event == 'open' and str(args[0]).endswith('mime.types'):
+        raise PermissionError('System MIME database is unavailable')
+sys.addaudithook(audit)
+import spreadsheet_layout
+"""
+        result = subprocess.run([sys.executable, '-c', script], cwd=Path(__file__).resolve().parents[1],
+                                capture_output=True, text=True)
+        self.assertEqual(result.returncode, 0, result.stderr)
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/reimburse/ExpensePreviewSheet.swift b/reimburse/ExpensePreviewSheet.swift
index 811f8a7..ec57a31 100644
--- a/reimburse/ExpensePreviewSheet.swift
+++ b/reimburse/ExpensePreviewSheet.swift
@@ -1,27 +1,4 @@
 import SwiftUI
-import Quartz
-
-struct SpreadsheetPreview: NSViewRepresentable {
-    let url: URL
-
-    func makeNSView(context: Context) -> QLPreviewView {
-        let view = QLPreviewView(frame: .zero, style: .normal)!
-        view.shouldCloseWithWindow = false
-        view.autostarts = true
-        view.previewItem = url as NSURL
-        return view
-    }
-
-    func updateNSView(_ view: QLPreviewView, context: Context) {
-        if view.previewItem?.previewItemURL != url {
-            view.previewItem = url as NSURL
-        }
-    }
-
-    static func dismantleNSView(_ view: QLPreviewView, coordinator: ()) {
-        view.close()
-    }
-}
 
 struct ExpensePreviewSheet: View {
     @EnvironmentObject var store: WorkspaceStore
@@ -47,7 +24,7 @@ struct ExpensePreviewSheet: View {
                     Button("取消生成", action: store.cancel)
                 }.frame(maxWidth: .infinity, maxHeight: .infinity)
             } else if let preview = store.expensePreview, let layout = preview.layout {
-                ExpenseSpreadsheetPreview(layout: layout).id(preview.file)
+                ExpenseDocumentPreview(layout: layout).id(preview.file)
                     .frame(maxWidth: .infinity, maxHeight: .infinity)
             } else {
                 ContentUnavailableView("暂时无法生成预览", systemImage: "doc.badge.ellipsis",
@@ -63,11 +40,6 @@ struct ExpensePreviewSheet: View {
                     .font(.caption).foregroundStyle(.orange)
                     .frame(maxWidth: .infinity, alignment: .leading).padding(.horizontal, 20).padding(.bottom, 10)
             }
-            if let warnings = store.expensePreview?.layout?.warnings, !warnings.isEmpty {
-                Text(warnings.joined(separator: "；"))
-                    .font(.caption).foregroundStyle(.orange)
-                    .frame(maxWidth: .infinity, alignment: .leading).padding(.horizontal, 20).padding(.bottom, 10)
-            }
             Divider()
             HStack {
                 Text("确认后保存此报销单")
@@ -82,7 +54,8 @@ struct ExpensePreviewSheet: View {
                     .disabled(store.expensePreview == nil || store.expensePreviewError != nil)
             }.padding(20).disabled(store.busy)
         }
-        .frame(width: 1080, height: 780)
+        .frame(width: min(1200, (NSScreen.main?.visibleFrame.width ?? 1280) - 80),
+               height: min(820, (NSScreen.main?.visibleFrame.height ?? 900) - 80))
         .interactiveDismissDisabled(store.busy)
         .onDisappear { store.discardExpensePreview() }
     }
diff --git a/reimburse/ExpenseTemplateSheet.swift b/reimburse/ExpenseTemplateSheet.swift
index 461313f..27afefb 100644
--- a/reimburse/ExpenseTemplateSheet.swift
+++ b/reimburse/ExpenseTemplateSheet.swift
@@ -85,7 +85,8 @@ struct ExpenseTemplateManager: View {
                 HStack(alignment: .top, spacing: 22) {
                     Group {
                         if let savedFile {
-                            SpreadsheetPreview(url: savedFile).id(savedFile)
+                            SpreadsheetFilePreview(url: savedFile, preferredSheet: store.expenseTemplate?.mapping.sheetName)
+                                .id(savedFile)
                         } else {
                             ContentUnavailableView("当前使用内置报销单", systemImage: "tablecells",
                                                    description: Text("没有本组模板也可以直接导出。\n如需更换，将 Excel 文件拖到上方。"))
@@ -161,7 +162,7 @@ private struct ExpenseTemplateEditor: View {
         HStack(alignment: .top, spacing: 22) {
             VStack(alignment: .leading, spacing: 8) {
                 Text("原始模板预览").font(.caption).foregroundStyle(.secondary)
-                SpreadsheetPreview(url: draft.source).id(draft.source)
+                SpreadsheetFilePreview(url: draft.source, preferredSheet: mapping.sheetName).id(draft.source)
                     .background(.white).clipShape(RoundedRectangle(cornerRadius: 10))
                 Text("这里显示导入文件原文；本次费用会在“预览报销单”中填入。")
                     .font(.caption).foregroundStyle(.secondary)
diff --git a/reimburse/NativeDiagnostics.swift b/reimburse/NativeDiagnostics.swift
index 2858484..92fc5f8 100644
--- a/reimburse/NativeDiagnostics.swift
+++ b/reimburse/NativeDiagnostics.swift
@@ -131,12 +131,23 @@ enum NativeDiagnostics {
             try ExpenseSummary.validateExportResult(customResult, matches: groupedState.matches)
             try ExpenseTemplateStorage.validateExport(customResult, template: savedTemplate)
             let previewMetadata = try JSONSerialization.jsonObject(with: customResult) as? [String: Any]
-            guard previewMetadata?["expensePreview"] as? String == "xlsx-layout-v2",
-                  let layoutObject = previewMetadata?["previewLayout"] else {
+            guard previewMetadata?["expensePreview"] as? String == "xlsx-layout-v4" else {
                 throw EngineFailure.message("应用内报销单预览未使用新版引擎")
             }
-            let layout = try JSONDecoder().decode(SpreadsheetLayout.self, from:
-                JSONSerialization.data(withJSONObject: layoutObject)).validated()
+            let layout = try SpreadsheetLayout.decode(previewMetadata?["previewLayout"])
+            let templatePreviewRequest: [String: Any] = [
+                "operation": "preview-expense-template",
+                "templatePath": try templateStorage.file(for: savedTemplate).path
+            ]
+            let templateDataBefore = try Data(contentsOf: templateStorage.file(for: savedTemplate))
+            let templatePreviewData = try await bridge.run(
+                request: JSONSerialization.data(withJSONObject: templatePreviewRequest)) { _, _ in }
+            let templateLayout = try JSONDecoder().decode(SpreadsheetLayout.self, from: templatePreviewData).validated()
+            guard !templateLayout.sheets.isEmpty,
+                  templateDataBefore == (try Data(contentsOf: templateStorage.file(for: savedTemplate))) else {
+                throw EngineFailure.message("模板预览修改了原始模板")
+            }
+            report["templatePreviewReadOnly"] = "passed"
             let generatedData = try Data(contentsOf: customDestination)
             let prepared = PreparedExpensePreview(
                 file: customDestination, requestDigest: try PreparedExpensePreview.digest(customRequest),
diff --git a/reimburse/SpreadsheetLayout.swift b/reimburse/SpreadsheetLayout.swift
index 3467dd2..d9b41d3 100644
--- a/reimburse/SpreadsheetLayout.swift
+++ b/reimburse/SpreadsheetLayout.swift
@@ -6,19 +6,23 @@ struct SpreadsheetLayout: Decodable {
     let sheets: [SpreadsheetSheet]
     let warnings: [String]
 
-    func validated() throws -> SpreadsheetLayout {
-        guard version == 1, !sheets.isEmpty, sheets.allSatisfy({
-            $0.width.isFinite && $0.height.isFinite && $0.width > 0 && $0.height > 0 &&
-            $0.cells.allSatisfy { cell in
-                [cell.x, cell.y, cell.width, cell.height, cell.style.fontSize,
-                 cell.overflowLeft, cell.overflowRight].allSatisfy(\.isFinite) &&
+    static func decode(_ object: Any?) throws -> Self {
+        guard let object else { throw ExpenseTemplateFailure.message("报销单排版数据缺失，请重新生成预览。") }
+        return try JSONDecoder().decode(Self.self, from: JSONSerialization.data(withJSONObject: object)).validated()
+    }
+
+    func validated() throws -> Self {
+        guard version == 4, !sheets.isEmpty, sheets.allSatisfy({ sheet in
+            sheet.width.isFinite && sheet.height.isFinite && sheet.width > 0 && sheet.height > 0 &&
+            sheet.cells.allSatisfy { cell in
+                [cell.x, cell.y, cell.width, cell.height, cell.overflowLeft,
+                 cell.overflowRight, cell.style.fontSize].allSatisfy(\.isFinite) &&
                 cell.x >= 0 && cell.y >= 0 && cell.width > 0 && cell.height > 0 &&
-                cell.style.fontSize > 0 && cell.overflowLeft >= 0 &&
-                cell.overflowLeft <= cell.x && cell.overflowRight >= cell.x + cell.width
+                cell.style.fontSize > 0 && cell.overflowLeft >= 0 && cell.overflowLeft <= cell.x &&
+                cell.overflowRight >= cell.x + cell.width && cell.overflowRight <= sheet.width + 0.01 &&
+                cell.y + cell.height <= sheet.height + 0.01
             }
-        }) else {
-            throw ExpenseTemplateFailure.message("报销单排版数据不完整，请重新生成预览。")
-        }
+        }) else { throw ExpenseTemplateFailure.message("报销单排版数据不完整，请重新生成预览。") }
         return self
     }
 }
@@ -32,24 +36,16 @@ struct SpreadsheetSheet: Decodable {
 
 struct SpreadsheetCell: Decodable {
     let reference: String
-    let x: Double
-    let y: Double
-    let width: Double
-    let height: Double
+    let x, y, width, height: Double
     let text: String
     let style: SpreadsheetStyle
-    let overflowLeft: Double
-    let overflowRight: Double
+    let overflowLeft, overflowRight: Double
     var rect: NSRect { NSRect(x: x, y: y, width: width, height: height) }
-    var textClip: NSRect {
-        NSRect(x: overflowLeft, y: y, width: overflowRight - overflowLeft, height: height)
-    }
+    var textClip: NSRect { NSRect(x: overflowLeft, y: y, width: overflowRight - overflowLeft, height: height) }
 }
 
 struct SpreadsheetBorder: Decodable {
-    let style: String
-    let color: String
-
+    let style, color: String
     var width: CGFloat {
         switch style {
         case "hair": 0.5
@@ -63,31 +59,24 @@ struct SpreadsheetBorder: Decodable {
 struct SpreadsheetStyle: Decodable {
     let font: String
     let fontSize: Double
-    let bold: Bool
-    let italic: Bool
-    let underline: Bool
-    let strike: Bool
-    let color: String
-    let fill: String
-    let horizontal: String
-    let vertical: String
-    let wrap: Bool
-    let shrink: Bool
+    let bold, italic, underline, strike: Bool
+    let color, fill, horizontal, vertical: String
+    let wrap, shrink: Bool
     let rotation: Int
     let indent: Double
     let borders: [String: SpreadsheetBorder]
+    let accounting: Bool
 
     @MainActor func resolvedFont(size: CGFloat? = nil) -> NSFont {
         let pointSize: CGFloat = size ?? CGFloat(fontSize * 4 / 3)
         let lower = font.lowercased()
         let fallback: String
-        if lower.contains("simsun") || font.contains("宋") {
-            fallback = "Songti SC"
-        } else if lower.contains("kai") || font.contains("楷") {
-            fallback = "Kaiti SC"
-        } else {
-            fallback = "PingFang SC"
-        }
+        // SimSun-ExtB is an extension font, not the installed Chinese Songti
+        // face. WPS uses a sans fallback for its unsupported base characters.
+        if lower.contains("extb") { fallback = "PingFang SC" }
+        else if lower.contains("simsun") || font.contains("宋") { fallback = "Songti SC" }
+        else if lower.contains("kai") || font.contains("楷") { fallback = "Kaiti SC" }
+        else { fallback = "Arial" }
         var result = NSFont(name: font, size: pointSize) ?? NSFont(name: fallback, size: pointSize)
             ?? NSFont.systemFont(ofSize: pointSize)
         if bold { result = NSFontManager.shared.convert(result, toHaveTrait: .boldFontMask) }
@@ -97,10 +86,7 @@ struct SpreadsheetStyle: Decodable {
 }
 
 enum SpreadsheetZoom: String, CaseIterable {
-    case width = "适合宽度"
-    case page = "整页"
-    case actual = "100%"
-
+    case width = "适合宽度", page = "整页", actual = "100%"
     func scale(sheet: SpreadsheetSheet, viewport: CGSize) -> CGFloat {
         let width = max(1, viewport.width - 48) / sheet.width
         let height = max(1, viewport.height - 48) / sheet.height
@@ -114,6 +100,8 @@ enum SpreadsheetZoom: String, CaseIterable {
 
 struct ExpenseSpreadsheetPreview: View {
     let layout: SpreadsheetLayout
+    var preferredSheet: String?
+    var onExpand: (() -> Void)?
     @State private var sheetIndex = 0
     @State private var zoom: SpreadsheetZoom = .width
     @State private var customScale: CGFloat?
@@ -121,49 +109,47 @@ struct ExpenseSpreadsheetPreview: View {
     var body: some View {
         GeometryReader { geometry in
             let sheet = layout.sheets[min(sheetIndex, layout.sheets.count - 1)]
-            let viewport = CGSize(width: geometry.size.width, height: max(1, geometry.size.height - 48))
+            let viewport = CGSize(width: geometry.size.width, height: max(1, geometry.size.height - 44))
             let scale = customScale ?? zoom.scale(sheet: sheet, viewport: viewport)
             VStack(spacing: 0) {
-                HStack(spacing: 12) {
+                HStack(spacing: 10) {
                     Picker("工作表", selection: $sheetIndex) {
-                        ForEach(layout.sheets.indices, id: \.self) { index in
-                            Text(layout.sheets[index].name).tag(index)
-                        }
-                    }.frame(maxWidth: 260)
-                    Spacer(minLength: 8)
+                        ForEach(layout.sheets.indices, id: \.self) { Text(layout.sheets[$0].name).tag($0) }
+                    }.labelsHidden().frame(minWidth: 90, maxWidth: 200)
+                    Spacer(minLength: 0)
                     Picker("缩放", selection: Binding(get: { customScale == nil ? zoom : nil }, set: {
                         if let mode = $0 { zoom = mode; customScale = nil }
                     })) {
-                        ForEach(SpreadsheetZoom.allCases, id: \.self) { mode in
-                            Text(mode.rawValue).tag(Optional(mode))
-                        }
-                    }.pickerStyle(.segmented).frame(width: 220)
-                    Button {
-                        customScale = max(0.1, scale - 0.1)
-                    } label: { Image(systemName: "minus.magnifyingglass") }
-                        .help("缩小").disabled(scale <= 0.1)
+                        ForEach(SpreadsheetZoom.allCases, id: \.self) { Text($0.rawValue).tag(Optional($0)) }
+                    }.pickerStyle(.segmented).labelsHidden().frame(width: 190)
+                    Button { customScale = max(0.1, scale - 0.1) } label: {
+                        Image(systemName: "minus.magnifyingglass")
+                    }.help("缩小").disabled(scale <= 0.1)
                     Text(Double(scale).formatted(.percent.precision(.fractionLength(0))))
-                        .font(.callout.monospacedDigit()).frame(width: 48)
-                    Button {
-                        customScale = min(2.5, scale + 0.1)
-                    } label: { Image(systemName: "plus.magnifyingglass") }
-                        .help("放大").disabled(scale >= 2.5)
-                }.padding(.horizontal, 20).frame(height: 48)
+                        .font(.callout.monospacedDigit()).frame(width: 45)
+                    Button { customScale = min(2.5, scale + 0.1) } label: {
+                        Image(systemName: "plus.magnifyingglass")
+                    }.help("放大").disabled(scale >= 2.5)
+                    if let onExpand {
+                        Button(action: onExpand) {
+                            Image(systemName: "arrow.up.left.and.arrow.down.right")
+                        }.help("在可调整大小的窗口中预览").accessibilityLabel("放大预览窗口")
+                    }
+                }.padding(.horizontal, 16).frame(height: 44)
                     .background(Color(nsColor: .windowBackgroundColor))
-                Divider()
                 ScrollView([.horizontal, .vertical]) {
                     SpreadsheetCanvas(sheet: sheet, scale: scale)
                         .frame(width: sheet.width * scale, height: sheet.height * scale)
-                        .background(.white)
-                        .overlay(Rectangle().stroke(Color.black.opacity(0.12), lineWidth: 1))
-                        .padding(24)
+                        .background(.white).padding(24)
                         .frame(minWidth: viewport.width, minHeight: viewport.height, alignment: .top)
+                }.background(Color(nsColor: NSColor(calibratedWhite: 0.92, alpha: 1)))
+                    .id(sheetIndex)
+            }.onChange(of: sheetIndex) { _, _ in customScale = nil }
+                .onChange(of: preferredSheet, initial: true) { _, name in
+                    if let name, let index = layout.sheets.firstIndex(where: { $0.name == name }) {
+                        sheetIndex = index
+                    }
                 }
-                .background(Color(nsColor: NSColor(calibratedWhite: 0.92, alpha: 1)))
-                .id(sheetIndex)
-            }
-            .onChange(of: zoom) { _, _ in customScale = nil }
-            .onChange(of: sheetIndex) { _, _ in customScale = nil }
         }
     }
 }
@@ -171,11 +157,7 @@ struct ExpenseSpreadsheetPreview: View {
 struct SpreadsheetCanvas: NSViewRepresentable {
     let sheet: SpreadsheetSheet
     let scale: CGFloat
-
-    func makeNSView(context: Context) -> SpreadsheetCanvasView {
-        SpreadsheetCanvasView(sheet: sheet, scale: scale)
-    }
-
+    func makeNSView(context: Context) -> SpreadsheetCanvasView { SpreadsheetCanvasView(sheet: sheet, scale: scale) }
     func updateNSView(_ view: SpreadsheetCanvasView, context: Context) {
         view.sheet = sheet
         view.scale = scale
@@ -184,11 +166,17 @@ struct SpreadsheetCanvas: NSViewRepresentable {
 }
 
 @MainActor final class SpreadsheetCanvasView: NSView {
+    struct TextPlacement {
+        let cell: SpreadsheetCell
+        let text: NSAttributedString
+        let box: NSRect
+        let overflow: NSRect?
+    }
+
     var sheet: SpreadsheetSheet
     var scale: CGFloat
     override var isFlipped: Bool { true }
     override var isOpaque: Bool { true }
-
     init(sheet: SpreadsheetSheet, scale: CGFloat) {
         self.sheet = sheet
         self.scale = scale
@@ -196,9 +184,91 @@ struct SpreadsheetCanvas: NSViewRepresentable {
         setAccessibilityLabel(sheet.name)
         setAccessibilityRole(.image)
     }
-
     required init?(coder: NSCoder) { nil }
 
+    static func color(_ hex: String) -> NSColor {
+        let value = UInt32(hex, radix: 16) ?? 0
+        return NSColor(srgbRed: CGFloat((value >> 16) & 255) / 255,
+                       green: CGFloat((value >> 8) & 255) / 255, blue: CGFloat(value & 255) / 255, alpha: 1)
+    }
+
+    func placement(for cell: SpreadsheetCell) -> TextPlacement {
+        let style = cell.style
+        let paragraph = NSMutableParagraphStyle()
+        paragraph.alignment = style.accounting ? .right :
+            style.horizontal == "center" || style.horizontal == "centerContinuous" ? .center :
+            style.horizontal == "right" ? .right : .left
+        paragraph.lineBreakMode = style.wrap || style.rotation == 255 ? .byWordWrapping : .byClipping
+        var text = style.rotation == 255 ? cell.text.filter { !$0.isNewline }.map(String.init).joined(separator: "\n") :
+            style.accounting ? cell.text.trimmingCharacters(in: .whitespaces) : cell.text
+        var font = style.resolvedFont()
+        var box = cell.rect.insetBy(dx: 3, dy: 1)
+        let indent = style.indent * font.pointSize * 0.9
+        if paragraph.alignment == .left { box.origin.x += indent }
+        box.size.width = max(1, box.width - indent)
+        if style.accounting { box.size.width = max(1, box.width - font.pointSize * 0.25) }
+        var attributes: [NSAttributedString.Key: Any] = [
+            .font: font, .foregroundColor: Self.color(style.color), .paragraphStyle: paragraph
+        ]
+        if style.underline { attributes[.underlineStyle] = NSUnderlineStyle.single.rawValue }
+        if style.strike { attributes[.strikethroughStyle] = NSUnderlineStyle.single.rawValue }
+        if style.wrap && style.rotation == 0 && !text.contains("\n") {
+            // A trailing Latin caption is a separate wrapping run from the
+            // Chinese label. Keep it together when it fits on its own line.
+            let source = text as NSString
+            let suffix = source.range(of: #"[A-Za-z][\x20-\x7E]*$"#, options: .regularExpression)
+            if suffix.location != NSNotFound && suffix.location > 0 {
+                let prefix = source.substring(to: suffix.location)
+                let tail = source.substring(from: suffix.location)
+                if prefix.unicodeScalars.contains(where: { (0x3400...0x9FFF).contains($0.value) }),
+                   tail.contains(" "),
+                   source.size(withAttributes: attributes).width > box.width,
+                   (prefix as NSString).size(withAttributes: attributes).width <= box.width,
+                   (tail as NSString).size(withAttributes: attributes).width <= box.width {
+                    text = prefix.trimmingCharacters(in: .whitespaces) + "\n" + tail
+                }
+            }
+        }
+        var natural = ceil((text as NSString).size(withAttributes: attributes).width)
+        if style.shrink && !style.wrap && style.rotation == 0 && natural > box.width {
+            font = style.resolvedFont(size: max(1, font.pointSize * box.width / natural))
+            attributes[.font] = font
+            natural = box.width
+        }
+        var overflow: NSRect?
+        if cell.textClip.width > cell.width && natural > box.width {
+            if paragraph.alignment == .right { box.origin.x -= natural - box.width }
+            else if paragraph.alignment == .center { box.origin.x -= (natural - box.width) / 2 }
+            box.size.width = natural
+            overflow = NSRect(x: box.minX, y: cell.y, width: box.width, height: cell.height)
+                .intersection(cell.textClip)
+        }
+        let attributed = NSAttributedString(string: text, attributes: attributes)
+        let measured = attributed.boundingRect(with: NSSize(width: box.width, height: 100000),
+                                               options: [.usesLineFragmentOrigin, .usesFontLeading])
+        let textHeight = min(box.height, ceil(measured.height))
+        if style.vertical == "center" { box.origin.y += (box.height - textHeight) / 2 }
+        else if style.vertical != "top" { box.origin.y += box.height - textHeight }
+        box.size.height = textHeight
+        return TextPlacement(cell: cell, text: attributed, box: box, overflow: overflow)
+    }
+
+    // Overflowing text occupies adjacent empty cells. Suppress both copies of
+    // each crossed vertical edge for that row, not just pixels behind glyphs.
+    func verticalSegments(x: CGFloat, top: CGFloat, bottom: CGFloat, overflow: [NSRect]) -> [ClosedRange<CGFloat>] {
+        var ranges = [top...bottom]
+        for rect in overflow where x > rect.minX && x < rect.maxX {
+            ranges = ranges.flatMap { range -> [ClosedRange<CGFloat>] in
+                guard rect.maxY > range.lowerBound && rect.minY < range.upperBound else { return [range] }
+                var remaining: [ClosedRange<CGFloat>] = []
+                if rect.minY > range.lowerBound { remaining.append(range.lowerBound...rect.minY) }
+                if rect.maxY < range.upperBound { remaining.append(rect.maxY...range.upperBound) }
+                return remaining
+            }
+        }
+        return ranges
+    }
+
     override func draw(_ dirtyRect: NSRect) {
         NSColor.white.setFill()
         dirtyRect.fill()
@@ -209,104 +279,56 @@ struct SpreadsheetCanvas: NSViewRepresentable {
         let visible = NSRect(x: dirtyRect.minX / scale, y: dirtyRect.minY / scale,
                              width: dirtyRect.width / scale, height: dirtyRect.height / scale).insetBy(dx: -3, dy: -3)
         let cells = sheet.cells.filter { $0.textClip.intersects(visible) }
-        // Fills, text and borders are separate passes so adjacent fills never
-        // erase shared cell borders. The entire sheet uses one uniform scale.
+        let placements = cells.filter { !$0.text.isEmpty }.map { placement(for: $0) }
+        let overflow = placements.compactMap(\.overflow)
         for cell in cells {
             Self.color(cell.style.fill).setFill()
             cell.rect.fill()
         }
-        for cell in cells where !cell.text.isEmpty { drawText(cell, context: context) }
-        for cell in cells { drawBorders(cell, context: context) }
-    }
-
-    static func color(_ hex: String) -> NSColor {
-        let value = UInt32(hex, radix: 16) ?? 0
-        return NSColor(srgbRed: CGFloat((value >> 16) & 255) / 255,
-                       green: CGFloat((value >> 8) & 255) / 255,
-                       blue: CGFloat(value & 255) / 255, alpha: 1)
-    }
-
-    private func drawText(_ cell: SpreadsheetCell, context: CGContext) {
-        let style = cell.style
-        let paragraph = NSMutableParagraphStyle()
-        paragraph.alignment = style.horizontal == "center" || style.horizontal == "centerContinuous" ? .center :
-            style.horizontal == "right" ? .right : .left
-        paragraph.lineBreakMode = style.wrap || style.rotation == 255 ? .byWordWrapping : .byClipping
-        let text = style.rotation == 255 ? cell.text.filter { !$0.isNewline }.map(String.init).joined(separator: "\n") : cell.text
-        var font = style.resolvedFont()
-        var box = cell.rect.insetBy(dx: 3, dy: 1)
-        let indent = style.indent * font.pointSize * 0.9
-        if paragraph.alignment == .left { box.origin.x += indent; box.size.width -= indent }
-        if paragraph.alignment == .right { box.size.width -= indent }
-        guard box.width > 0 && box.height > 0 else { return }
-        var attributes: [NSAttributedString.Key: Any] = [
-            .font: font, .foregroundColor: Self.color(style.color), .paragraphStyle: paragraph
-        ]
-        if style.underline { attributes[.underlineStyle] = NSUnderlineStyle.single.rawValue }
-        if style.strike { attributes[.strikethroughStyle] = NSUnderlineStyle.single.rawValue }
-        if style.shrink && !style.wrap && style.rotation == 0 {
-            let natural = (text as NSString).size(withAttributes: attributes).width
-            if natural > box.width {
-                font = style.resolvedFont(size: max(1, font.pointSize * box.width / natural))
-                attributes[.font] = font
-            }
+        // Strong shared edges win over thin edges regardless of XML cell order.
+        let edges = cells.flatMap { cell in cell.style.borders.map { (cell, $0.key, $0.value) } }
+            .sorted { $0.2.width < $1.2.width }
+        for (cell, edge, border) in edges {
+            drawBorder(cell, edge: edge, border: border, overflow: overflow, context: context)
         }
-        context.saveGState()
-        defer { context.restoreGState() }
-        context.clip(to: cell.textClip)
-        if cell.textClip.width > cell.width {
-            let natural = ceil((text as NSString).size(withAttributes: attributes).width)
-            if natural > box.width {
-                if paragraph.alignment == .right { box.origin.x -= natural - box.width }
-                else if paragraph.alignment == .center { box.origin.x -= (natural - box.width) / 2 }
-                box.size.width = natural
-            }
-        }
-        if (1...180).contains(style.rotation) {
-            let angle = style.rotation <= 90 ? style.rotation : 90 - style.rotation
-            context.translateBy(x: box.midX, y: box.midY)
-            context.rotate(by: -CGFloat(angle) * .pi / 180)
-            box = NSRect(x: -box.height / 2, y: -box.width / 2, width: box.height, height: box.width)
-        }
-        let attributed = NSAttributedString(string: text, attributes: attributes)
-        let options: NSString.DrawingOptions = [.usesLineFragmentOrigin, .usesFontLeading]
-        let measured = attributed.boundingRect(with: NSSize(width: box.width, height: 100000), options: options)
-        let textHeight = min(box.height, ceil(measured.height))
-        if style.vertical == "center" { box.origin.y += (box.height - textHeight) / 2 }
-        else if style.vertical != "top" { box.origin.y += box.height - textHeight }
-        box.size.height = textHeight
-        attributed.draw(with: box, options: options)
-    }
-
-    private func drawBorders(_ cell: SpreadsheetCell, context: CGContext) {
-        let rect = cell.rect
-        for (edge, border) in cell.style.borders {
-            let start: CGPoint
-            let end: CGPoint
-            switch edge {
-            case "top": start = CGPoint(x: rect.minX, y: rect.minY); end = CGPoint(x: rect.maxX, y: rect.minY)
-            case "bottom": start = CGPoint(x: rect.minX, y: rect.maxY); end = CGPoint(x: rect.maxX, y: rect.maxY)
-            case "left": start = CGPoint(x: rect.minX, y: rect.minY); end = CGPoint(x: rect.minX, y: rect.maxY)
-            default: start = CGPoint(x: rect.maxX, y: rect.minY); end = CGPoint(x: rect.maxX, y: rect.maxY)
-            }
+        for placement in placements {
             context.saveGState()
-            context.setStrokeColor(Self.color(border.color).cgColor)
-            context.setLineWidth(border.style == "double" ? 1 : border.width)
-            if border.style.lowercased().contains("dash") { context.setLineDash(phase: 0, lengths: [5, 3]) }
-            if border.style == "dotted" { context.setLineDash(phase: 0, lengths: [1, 2]) }
-            if border.style == "double" {
-                for offset in [-1.0, 1.0] {
-                    let dx = edge == "left" || edge == "right" ? offset : 0
-                    let dy = dx == 0 ? offset : 0
-                    context.move(to: CGPoint(x: start.x + dx, y: start.y + dy))
-                    context.addLine(to: CGPoint(x: end.x + dx, y: end.y + dy))
-                }
+            context.clip(to: placement.cell.textClip)
+            if (1...180).contains(placement.cell.style.rotation) {
+                let rotation = placement.cell.style.rotation
+                let angle = rotation <= 90 ? rotation : 90 - rotation
+                context.translateBy(x: placement.cell.rect.midX, y: placement.cell.rect.midY)
+                context.rotate(by: -CGFloat(angle) * .pi / 180)
+                placement.text.draw(at: NSPoint(x: -placement.box.width / 2, y: -placement.box.height / 2))
             } else {
-                context.move(to: start)
-                context.addLine(to: end)
+                placement.text.draw(with: placement.box, options: [.usesLineFragmentOrigin, .usesFontLeading])
             }
-            context.strokePath()
             context.restoreGState()
         }
     }
+
+    private func drawBorder(_ cell: SpreadsheetCell, edge: String, border: SpreadsheetBorder,
+                            overflow: [NSRect], context: CGContext) {
+        let rect = cell.rect
+        let vertical = edge == "left" || edge == "right"
+        let fixed = vertical ? (edge == "left" ? rect.minX : rect.maxX) :
+            (edge == "top" ? rect.minY : rect.maxY)
+        let ranges = vertical ? verticalSegments(x: fixed, top: rect.minY, bottom: rect.maxY, overflow: overflow) :
+            [rect.minX...rect.maxX]
+        context.saveGState()
+        defer { context.restoreGState() }
+        context.setStrokeColor(Self.color(border.color).cgColor)
+        context.setLineWidth(border.style == "double" ? 1 : border.width)
+        if border.style.lowercased().contains("dash") { context.setLineDash(phase: 0, lengths: [5, 3]) }
+        if border.style == "dotted" { context.setLineDash(phase: 0, lengths: [1, 2]) }
+        for range in ranges {
+            for offset in border.style == "double" ? [-1.0, 1.0] : [0.0] {
+                context.move(to: vertical ? CGPoint(x: fixed + offset, y: range.lowerBound) :
+                    CGPoint(x: range.lowerBound, y: fixed + offset))
+                context.addLine(to: vertical ? CGPoint(x: fixed + offset, y: range.upperBound) :
+                    CGPoint(x: range.upperBound, y: fixed + offset))
+            }
+        }
+        context.strokePath()
+    }
 }
diff --git a/reimburse/SpreadsheetPreview.swift b/reimburse/SpreadsheetPreview.swift
new file mode 100644
index 0000000..f105041
--- /dev/null
+++ b/reimburse/SpreadsheetPreview.swift
@@ -0,0 +1,143 @@
+import AppKit
+import Combine
+import SwiftUI
+
+struct SpreadsheetFilePreview: View {
+    let url: URL
+    var preferredSheet: String?
+    @State private var layout: SpreadsheetLayout?
+    @State private var error: String?
+    @State private var attempt = 0
+
+    private struct Request: Equatable {
+        let url: URL
+        let attempt: Int
+    }
+
+    var body: some View {
+        Group {
+            if let layout {
+                ExpenseDocumentPreview(layout: layout, title: "报销单模板", preferredSheet: preferredSheet)
+            } else if let error {
+                VStack(spacing: 12) {
+                    ContentUnavailableView("模板预览暂不可用", systemImage: "doc.badge.exclamationmark",
+                                           description: Text(error))
+                    Button("重新加载") { attempt += 1 }
+                }
+            } else {
+                ProgressView("正在读取模板预览…").frame(maxWidth: .infinity, maxHeight: .infinity)
+            }
+        }
+        .task(id: Request(url: url, attempt: attempt)) {
+            layout = nil
+            error = nil
+            // Independent from the scan/import worker: dismissing a preview must
+            // not cancel an import or another workspace operation.
+            let engine = EngineBridge()
+            do {
+                try Task.checkCancellation()
+                let request = try JSONSerialization.data(withJSONObject: [
+                    "operation": "preview-expense-template", "templatePath": url.path
+                ])
+                let data = try await withTaskCancellationHandler {
+                    try await engine.run(request: request) { _, _ in }
+                } onCancel: {
+                    engine.cancel()
+                }
+                try Task.checkCancellation()
+                let decoded = try JSONDecoder().decode(SpreadsheetLayout.self, from: data).validated()
+                layout = decoded
+            } catch {
+                guard !Task.isCancelled else { return }
+                self.error = error.localizedDescription
+            }
+        }
+    }
+}
+
+struct ExpenseDocumentPreview: View {
+    let layout: SpreadsheetLayout
+    var title = "报销单预览"
+    var preferredSheet: String?
+    @StateObject private var expanded = SpreadsheetPreviewWindow()
+
+    private var warnings: [String] {
+        var warnings = layout.warnings
+        let missing = Array(Set(layout.sheets.flatMap(\.cells).map(\.style.font)))
+            .filter { NSFont(name: $0, size: 12) == nil }.sorted()
+        if !missing.isEmpty {
+            warnings.append("本机缺少字体，预览已使用替代字体：\(missing.prefix(3).joined(separator: "、"))\(missing.count > 3 ? "等" : "")")
+        }
+        return warnings
+    }
+
+    var body: some View {
+        VStack(spacing: 0) {
+            ExpenseSpreadsheetPreview(layout: layout, preferredSheet: preferredSheet) {
+                expanded.show(layout: layout, title: title, preferredSheet: preferredSheet)
+            }
+                .frame(maxWidth: .infinity, maxHeight: .infinity)
+                .background(.white)
+            if !warnings.isEmpty {
+                Text(warnings.joined(separator: "；"))
+                    .font(.caption).foregroundStyle(.secondary)
+                    .frame(maxWidth: .infinity, alignment: .leading)
+                    .padding(.horizontal, 12).padding(.vertical, 8)
+            }
+        }
+        .onChange(of: preferredSheet) { _, _ in
+            expanded.update(layout: layout, title: title, preferredSheet: preferredSheet)
+        }
+        .onDisappear { expanded.close() }
+    }
+}
+
+@MainActor
+final class SpreadsheetPreviewWindow: NSObject, ObservableObject, NSWindowDelegate {
+    private(set) var window: NSWindow?
+    private var preview: NSHostingView<ExpenseSpreadsheetPreview>?
+
+    static func initialFrame(in screen: NSRect) -> NSRect {
+        let available = screen.insetBy(dx: 24, dy: 24)
+        let size = NSSize(width: min(1440, available.width), height: min(1000, available.height))
+        return NSRect(x: available.midX - size.width / 2, y: available.midY - size.height / 2,
+                      width: size.width, height: size.height)
+    }
+
+    func show(layout: SpreadsheetLayout, title: String, preferredSheet: String? = nil) {
+        if let window {
+            update(layout: layout, title: title, preferredSheet: preferredSheet)
+            window.makeKeyAndOrderFront(nil)
+            return
+        }
+        let screen = NSApp.keyWindow?.screen ?? NSScreen.main
+        let frame = Self.initialFrame(in: screen?.visibleFrame ?? NSRect(x: 0, y: 0, width: 1280, height: 800))
+        let window = NSWindow(contentRect: frame, styleMask: [.titled, .closable, .miniaturizable, .resizable],
+                              backing: .buffered, defer: false)
+        window.setFrame(frame, display: false)
+        window.minSize = NSSize(width: 640, height: 420)
+        window.collectionBehavior = [.fullScreenPrimary]
+        window.isReleasedWhenClosed = false
+        window.delegate = self
+        window.title = title
+        let preview = NSHostingView(rootView: ExpenseSpreadsheetPreview(layout: layout, preferredSheet: preferredSheet))
+        preview.frame = NSRect(origin: .zero, size: frame.size)
+        preview.autoresizingMask = [.width, .height]
+        window.contentView = preview
+        self.window = window
+        self.preview = preview
+        window.makeKeyAndOrderFront(nil)
+    }
+
+    func update(layout: SpreadsheetLayout, title: String, preferredSheet: String? = nil) {
+        window?.title = title
+        preview?.rootView = ExpenseSpreadsheetPreview(layout: layout, preferredSheet: preferredSheet)
+    }
+
+    func close() { window?.close() }
+
+    func windowWillClose(_ notification: Notification) {
+        preview = nil
+        window = nil
+    }
+}
diff --git a/reimburse/WorkspaceStore.swift b/reimburse/WorkspaceStore.swift
index 759843a..ea4e0fb 100644
--- a/reimburse/WorkspaceStore.swift
+++ b/reimburse/WorkspaceStore.swift
@@ -447,12 +447,10 @@ final class WorkspaceStore: ObservableObject {
                     try ExpenseSummary.validateExportResult(result, matches: snapshot.matches)
                     if let template = snapshot.template { try ExpenseTemplateStorage.validateExport(result, template: template) }
                     let metadata = try JSONSerialization.jsonObject(with: result) as? [String: Any]
-                    guard metadata?["expensePreview"] as? String == "xlsx-layout-v2",
-                          let layoutObject = metadata?["previewLayout"] else {
+                    guard metadata?["expensePreview"] as? String == "xlsx-layout-v4" else {
                         throw ExpenseTemplateFailure.message("当前引擎不支持报销单预览，请重新构建应用。")
                     }
-                    let layout = try JSONDecoder().decode(SpreadsheetLayout.self, from:
-                        JSONSerialization.data(withJSONObject: layoutObject)).validated()
+                    let layout = try SpreadsheetLayout.decode(metadata?["previewLayout"])
                     expensePreview = PreparedExpensePreview(
                         file: file, requestDigest: digest,
                         fileDigest: ExpenseTemplateStorage.fingerprint(try Data(contentsOf: file)),
diff --git a/tests/SpreadsheetLayoutTests.swift b/tests/SpreadsheetLayoutTests.swift
index a38f5d3..49adfc3 100644
--- a/tests/SpreadsheetLayoutTests.swift
+++ b/tests/SpreadsheetLayoutTests.swift
@@ -4,51 +4,119 @@ import SwiftUI
 @main
 struct SpreadsheetLayoutTests {
     @MainActor static func main() throws {
-        let source = URL(fileURLWithPath: CommandLine.arguments[1])
-        let layout = try JSONDecoder().decode(SpreadsheetLayout.self, from: Data(contentsOf: source)).validated()
+        _ = NSApplication.shared
+        NSApplication.shared.appearance = NSAppearance(named: .aqua)
+        let data = try Data(contentsOf: URL(fileURLWithPath: CommandLine.arguments[1]))
+        let layout = try JSONDecoder().decode(SpreadsheetLayout.self, from: data).validated()
         let sheet = layout.sheets[0]
-        let narrow = SpreadsheetZoom.width.scale(sheet: sheet, viewport: CGSize(width: 800, height: 500))
-        let wide = SpreadsheetZoom.width.scale(sheet: sheet, viewport: CGSize(width: 1800, height: 900))
-        precondition(narrow * sheet.width <= 752)
-        precondition(wide == 1)
-        let page = SpreadsheetZoom.page.scale(sheet: sheet, viewport: CGSize(width: 800, height: 500))
-        precondition(page * sheet.height <= 452)
-        precondition(SpreadsheetZoom.actual.scale(sheet: sheet, viewport: .zero) == 1)
-        precondition(sheet.cells.first { $0.reference == "H30" }?.style.rotation == 255)
-        precondition(sheet.cells.first { $0.reference == "C25" }?.text == "001234567890")
-        precondition(sheet.cells.first { $0.reference == "F27" }?.text.trimmingCharacters(in: .whitespaces) == "544.30")
-        let signature = sheet.cells.first { $0.reference == "A30" }!
-        precondition(signature.textClip.width > signature.width)
-        print("Workbook layout, zoom bounds, vertical text and exact values passed")
-        if CommandLine.arguments.count > 2 {
-            let folder = URL(fileURLWithPath: CommandLine.arguments[2], isDirectory: true)
-            try FileManager.default.createDirectory(at: folder, withIntermediateDirectories: true)
-            _ = NSApplication.shared
-            NSApplication.shared.appearance = NSAppearance(named: .aqua)
-            let canvas = SpreadsheetCanvasView(sheet: sheet, scale: 1)
-            try capture(canvas, to: folder.appendingPathComponent("sheet.png"))
-            for size in [CGSize(width: 1080, height: 620), CGSize(width: 820, height: 480)] {
-                let host = NSHostingView(rootView: ExpenseSpreadsheetPreview(layout: layout))
-                host.frame = NSRect(origin: .zero, size: size)
-                let window = NSWindow(contentRect: host.frame, styleMask: [.borderless], backing: .buffered, defer: false)
-                window.contentView = host
-                host.layoutSubtreeIfNeeded()
-                RunLoop.current.run(until: Date().addingTimeInterval(0.5))
-                try capture(host, to: folder.appendingPathComponent("preview-\(Int(size.width)).png"))
-                window.orderOut(nil)
-            }
-            print("Native preview snapshots written to \(folder.path)")
+        let cells = Dictionary(uniqueKeysWithValues: sheet.cells.map { ($0.reference, $0) })
+        let canvas = SpreadsheetCanvasView(sheet: sheet, scale: 1)
+        let placements = sheet.cells.filter { !$0.text.isEmpty }.map { canvas.placement(for: $0) }
+        let overflow = placements.compactMap(\.overflow)
+        for ref in ["A30", "D30", "A31"] {
+            let cell = cells[ref]!
+            precondition(canvas.verticalSegments(x: cell.rect.maxX, top: cell.rect.minY,
+                                                bottom: cell.rect.maxY, overflow: overflow).isEmpty,
+                         "A vertical line still crosses \(ref)")
         }
+        let boundary = cells["B30"]!
+        precondition(!canvas.verticalSegments(x: boundary.rect.maxX, top: boundary.rect.minY,
+                                             bottom: boundary.rect.maxY, overflow: overflow).isEmpty,
+                     "An unrelated border was removed")
+        let anchor = cells["A30"]!
+        let shortLabel = SpreadsheetCell(reference: anchor.reference, x: anchor.x, y: anchor.y,
+                                         width: anchor.width, height: anchor.height, text: "签",
+                                         style: anchor.style, overflowLeft: anchor.overflowLeft,
+                                         overflowRight: anchor.overflowRight)
+        precondition(canvas.placement(for: shortLabel).overflow == nil)
+        let blockedLabel = SpreadsheetCell(reference: anchor.reference, x: anchor.x, y: anchor.y,
+                                           width: anchor.width, height: anchor.height, text: anchor.text,
+                                           style: anchor.style, overflowLeft: anchor.x,
+                                           overflowRight: anchor.x + anchor.width)
+        precondition(canvas.placement(for: blockedLabel).overflow == nil)
+        for ref in ["F27", "H29"] {
+            let placed = canvas.placement(for: cells[ref]!)
+            let paragraph = placed.text.attribute(.paragraphStyle, at: 0, effectiveRange: nil) as! NSParagraphStyle
+            precondition(paragraph.alignment == .right)
+            precondition(placed.text.string == "447.00")
+        }
+        let signature = canvas.placement(for: cells["H30"]!)
+        precondition(canvas.placement(for: cells["A29"]!).text.string.contains("\nTOTAL PAYMENT (A)"))
+        precondition(signature.text.string == "收\n款\n人\n签\n字")
+        precondition(abs(signature.box.maxY - cells["H30"]!.rect.maxY) < 2)
+        precondition(cells["H30"]!.style.borders["right"]?.style == "medium")
+        for size in [CGSize(width: 800, height: 500), CGSize(width: 1200, height: 760)] {
+            let scale = SpreadsheetZoom.width.scale(sheet: sheet, viewport: size)
+            precondition(scale * sheet.width <= size.width - 48)
+            let page = SpreadsheetZoom.page.scale(sheet: sheet, viewport: size)
+            precondition(page * sheet.height <= size.height - 48)
+        }
+        let expanded = SpreadsheetPreviewWindow()
+        expanded.show(layout: layout, title: "Test")
+        let first = expanded.window!
+        precondition(first.styleMask.contains(.resizable))
+        expanded.show(layout: layout, title: "Template")
+        precondition(expanded.window === first)
+        expanded.close()
+        precondition(expanded.window == nil)
+        print("Overflow borders, accounting alignment, stacked signature, merge edges, zoom and window cleanup passed")
+
+        let folder = URL(fileURLWithPath: CommandLine.arguments[2], isDirectory: true)
+        try FileManager.default.createDirectory(at: folder, withIntermediateDirectories: true)
+        let bitmap = try capture(canvas, to: folder.appendingPathComponent("sheet.png"))
+        let ratio = CGFloat(bitmap.pixelsWide) / canvas.bounds.width
+        func luminance(x: CGFloat, y: CGFloat) -> CGFloat {
+            let color = bitmap.colorAt(x: Int(x * ratio), y: Int(y * ratio))!.usingColorSpace(.deviceRGB)!
+            return (color.redComponent + color.greenComponent + color.blueComponent) / 3
+        }
+        // Pixel checks away from glyphs catch border regressions in actual drawing,
+        // not just matching JSON models or two instances of the same renderer.
+        for ref in ["A30", "D30", "A31"] {
+            let cell = cells[ref]!
+            precondition(luminance(x: cell.rect.maxX, y: cell.rect.minY + 15) > 0.97)
+        }
+        precondition(luminance(x: boundary.rect.maxX, y: boundary.rect.minY + 15) < 0.9)
+        for width in [620, 820, 1200] {
+            let host = NSHostingView(rootView: ExpenseDocumentPreview(layout: layout))
+            let window = NSWindow(contentRect: NSRect(x: 0, y: 0, width: width, height: 700),
+                                  styleMask: [.borderless], backing: .buffered, defer: false)
+            window.contentView = host
+            host.layoutSubtreeIfNeeded()
+            RunLoop.current.run(until: Date().addingTimeInterval(0.3))
+            _ = try capture(host, to: folder.appendingPathComponent("preview-\(width).png"))
+            window.orderOut(nil)
+        }
+        if CommandLine.arguments.count > 3 {
+            let alternateData = try Data(contentsOf: URL(fileURLWithPath: CommandLine.arguments[3]))
+            let alternate = try JSONDecoder().decode(SpreadsheetLayout.self, from: alternateData).validated()
+            let host = NSHostingView(rootView: ExpenseDocumentPreview(layout: alternate,
+                                                                     title: "报销单模板", preferredSheet: "说明页"))
+            let window = NSWindow(contentRect: NSRect(x: 0, y: 0, width: 620, height: 500),
+                                  styleMask: [.borderless], backing: .buffered, defer: false)
+            window.contentView = host
+            host.layoutSubtreeIfNeeded()
+            RunLoop.current.run(until: Date().addingTimeInterval(0.3))
+            _ = try capture(host, to: folder.appendingPathComponent("template-selected-sheet.png"))
+            precondition(containsCanvas(host, named: "说明页"), "Template sheet selection was ignored")
+            host.rootView = ExpenseDocumentPreview(layout: alternate, title: "报销单模板", preferredSheet: "横向费用单")
+            host.layoutSubtreeIfNeeded()
+            RunLoop.current.run(until: Date().addingTimeInterval(0.3))
+            _ = try capture(host, to: folder.appendingPathComponent("template-alternate.png"))
+            precondition(containsCanvas(host, named: "横向费用单"), "Changing the mapping sheet did not change the preview")
+            window.orderOut(nil)
+        }
+        print("Rendered pixel checks passed; screenshots written to \(folder.path)")
     }
 
-    @MainActor static func capture(_ view: NSView, to file: URL) throws {
-        guard let bitmap = view.bitmapImageRepForCachingDisplay(in: view.bounds) else {
-            throw ExpenseTemplateFailure.message("Cannot create preview snapshot")
-        }
+    @MainActor static func containsCanvas(_ view: NSView, named: String) -> Bool {
+        if let canvas = view as? SpreadsheetCanvasView, canvas.sheet.name == named { return true }
+        return view.subviews.contains { containsCanvas($0, named: named) }
+    }
+
+    @MainActor static func capture(_ view: NSView, to url: URL) throws -> NSBitmapImageRep {
+        let bitmap = view.bitmapImageRepForCachingDisplay(in: view.bounds)!
         view.cacheDisplay(in: view.bounds, to: bitmap)
-        guard let png = bitmap.representation(using: .png, properties: [:]) else {
-            throw ExpenseTemplateFailure.message("Cannot encode preview snapshot")
-        }
-        try png.write(to: file)
+        try bitmap.representation(using: .png, properties: [:])!.write(to: url)
+        return bitmap
     }
 }