diff --git a/DESIGN.md b/DESIGN.md
index be1358f..ddb97b6 100644
--- a/DESIGN.md
+++ b/DESIGN.md
@@ -21,6 +21,9 @@
 ## Product goals
 
 - Build a useful personal reading/research shelf backed by a real SQLite file.
+- Ship a deterministic 256-record fixture by default so pagination and warm
+  incremental updates are exercised on a realistic surface; fixture size and
+  page size remain configurable for focused tests.
 - Make triage, selection, progress updates, filtering, pagination, and
   recovery feel like one coherent product rather than isolated demos.
 - Exercise existing ETAF components through composition before adding any new
@@ -67,7 +70,7 @@
 - Typography: readable proportional labels with compact monospace metadata;
   title and selected record use bold weight, not oversized headings.
 - Spacing/layout rhythm: 1-cell outer rhythm, 2-cell panel padding, 1-cell
-  grid gaps, and stable intrinsic control widths.
+  workspace gaps, and stable intrinsic control widths.
 - Shape/elevation: thin borders, small radius-like grouped rows where Ebox
   permits, no floating overlays or decorative shadows.
 - Motion: immediate state changes; no timer-driven animation; reduced-motion
@@ -114,14 +117,12 @@
 
 ## Responsive behavior
 
-- Wide/fullscreen: three-column grid (rail / list / detail).
-- Compact: the same grid uses zero-minimum fractional tracks; rail, list, and
-  detail shrink within the viewport instead of imposing min-content overflow,
-  while the action group wraps through Flex and long table cells wrap inside
-  their tracks.
-- Use `grid` for the product skeleton, `flex` for toolbars/action groups, and
-  `row` only for compact intrinsic controls. `minmax(0, fr)` is the responsive
-  track contract; do not reintroduce fixed child widths at the shell boundary.
+- Wide/fullscreen: one Flex line presents rail / list / detail as three columns.
+- Medium: rail and list remain together while detail wraps to the next line.
+- Narrow: the same three Components wrap in document order into a vertical flow.
+- The shell uses one wrapping Flex composition with semantic basis/grow weights;
+  it does not read window size or maintain breakpoint state. Use `row` only for
+  compact intrinsic controls and Flex whenever free space must be distributed.
 
 ## Interaction states
 
@@ -132,6 +133,8 @@
 - Success: mutation shows `✓ Saved locally` and updates `updated` metadata.
 - Disabled: `Finish` is disabled for finished records; `+10%` is disabled at
   100%; archive is disabled while loading.
+- Page density: activating `Rows N ✎` uses Emacs's native minibuffer to accept
+  any integer from 1 through 100, then reloads page one.
 
 ## Content voice
 
@@ -147,8 +150,11 @@
   sibling `etaf-sqlite` package; no HTML/CSS runtime dependency.
 - Data schema: one typed `reading_items` SQLite table with id/title/author/
   kind/status/progress/priority/starred/note/updated columns.
+- Pressure fixture: `etaf-research-shelf-fixture-size` defaults to 256 and
+  `etaf-research-shelf-page-size` defaults to 12; existing local rows are
+  preserved and missing fixture rows are topped up with fresh IDs.
 - Performance: one Data mutation -> one Runtime generation/publication; normal
-  warm actions remain under the existing 100ms p50 target.
+  warm actions remain under the accepted 105ms p50 target.
 - Compatibility: one same-basename `research-shelf` pair only; old console
   examples are removed from the active manifest and compile surface.
 - Verification: SQLite temp-file integration tests, pair mount/remount tests,
diff --git a/DESIGN.zh-CN.md b/DESIGN.zh-CN.md
index 2793b99..9a209ca 100644
--- a/DESIGN.zh-CN.md
+++ b/DESIGN.zh-CN.md
@@ -14,6 +14,8 @@
 Research Shelf 是一个真正有用的本地研究/阅读架：SQLite 保存书籍、论文、
 文章和笔记，用户可以筛选、分页、选择一条记录、更新进度、完成、收藏和归档。
 它不是把 API 名称堆成控制台，而是用一个连贯 workflow 验证 ETAF 的组合能力。
+Playground 默认安装确定性的 256 条 fixture、每页 12 条，用于真实验证分页、DataGrid
+增量更新和 SQLite 查询压力；fixture 数量和 page size 都可以配置。
 
 ## 结构与分层
 
@@ -52,8 +54,8 @@ Component 边界，避免新增 helper 层或抽象泄漏。
   墙、假图表、彩虹渐变和装饰性噪声。
 - 色彩：ink `#172033`、paper `#F7F3EA`、cobalt `#3657D6`、mint `#3E9B8F`、
   coral `#D86B5D`、amber `#C58A3A`、muted `#6D7482`。
-- 节奏：1 格外部节奏、2 格 panel padding、1 格 grid gap，控件保持 intrinsic
-  宽度；`grid` 负责页面骨架，`flex` 负责 toolbar/action group。
+- 节奏：1 格外部节奏、2 格 panel padding、1 格 workspace gap，控件保持
+  intrinsic 宽度；需要分配剩余空间或换行时统一使用 `flex`。
 - 状态：文字和 Unicode 同时表达状态：`⌕`、`★`、`✓`、`◷`、`↗`、`⚠`、`·`。
 - 动效：状态立即可见，不依赖 timer animation，默认支持 reduced motion。
 
@@ -61,6 +63,8 @@ Component 边界，避免新增 helper 层或抽象泄漏。
 
 - 筛选：All、In progress、Unread、Finished、Starred。
 - 列表：DataGrid 行单选，重复点击可以重新选择；分页按钮在边界处 disabled。
+- 每页行数：激活 `Rows N ✎` 后使用 Emacs 原生 minibuffer 输入 1–100 的整数，
+  应用后回到第一页。
 - 详情：`+ 10%`、`✓ Finish`、`☆/★ Star`、`Archive`；完成或 100% 时正确禁用。
 - 存储：成功显示 `✓ Saved locally`，失败保留当前可用内容并提供 Reload。
 - 主题：Light/Dark 由 checkbox 控制；文字、对比度和布局都应保持可读。
@@ -68,16 +72,19 @@ Component 边界，避免新增 helper 层或抽象泄漏。
 
 ## 响应式与验证
 
-- Wide/fullscreen 使用 rail / list / detail 三列 grid。
-- Compact 时仍使用三列骨架，但每列采用零最小值的 fractional track，在 viewport
-  内收缩而不是被 min-content 撑出边界；长表格单元格在自己的 track 内换行，动作组
-  由 Flex 自动换行。不要在 shell 边界重新引入固定宽度。
-- `minmax(0, fr)` 是响应式 track 合同；`grid` 负责骨架，`flex` 负责 toolbar/action
-  group，`row` 只负责紧凑 intrinsic 控件，所有操作控件仍保持独立 hover/focus 语义。
+- Wide/fullscreen：rail / list / detail 位于同一条 Flex line，呈现三栏。
+- Medium：rail 与 list 保持同排，detail 自动换到下一行。
+- Narrow：同一组三个 Component 按文档顺序自动变为纵向流。
+- Shell 只使用一套带 basis/grow 权重的 wrapping Flex，不读取窗口宽度、不维护
+  breakpoint 状态；`row` 只负责紧凑 intrinsic 控件，所有操作控件仍保持独立
+  hover/focus 语义。
 - 用 SQLite 临时文件测试 mount/remount、筛选、分页、重复选行、mutation、错误
   状态和 cleanup；GUI 用干净 fullscreen 单窗口截图验证真实布局。
 - 目标：一次 Data mutation 对应一次 Runtime generation/publication；warm 交互
-  维持现有 100ms p50 预算。
+  维持已接受的 105ms p50 预算。
+- 压测入口：`etaf-research-shelf-fixture-size` 默认 256，
+  `etaf-research-shelf-page-size` 默认 12；已有本地记录保留，不足部分使用新 ID
+  补齐 fixture。
 
 ## 待 review
 
diff --git a/README.md b/README.md
index 849651b..feeeba6 100644
--- a/README.md
+++ b/README.md
@@ -14,3 +14,10 @@ before adding abstractions.
 
 Run `make check EMACS=/Applications/Emacs.app/Contents/MacOS/Emacs`.
 Run `make perf` for the 1413×62 warm row-selection/theme latency gate.
+
+The example installs a deterministic 256-record SQLite fixture with 12 records
+per page. Bind `etaf-research-shelf-fixture-size` and
+`etaf-research-shelf-page-size` for smaller tests or larger pressure runs.
+In the UI, activate `Rows N ✎` to enter any value from 1 through 100. The
+workspace is one responsive wrapping Flex composition: three columns when
+wide, rail/list plus wrapped detail at medium widths, and vertical when narrow.
diff --git a/README.zh-CN.md b/README.zh-CN.md
index d071679..f892dd4 100644
--- a/README.zh-CN.md
+++ b/README.zh-CN.md
@@ -12,3 +12,8 @@ schema、palette、refs 与 handlers 不能泄漏进框架。
 
 验证命令：`make check EMACS=/Applications/Emacs.app/Contents/MacOS/Emacs`。
 性能门禁：`make perf`（1413×62 viewport 的 warm 选行/主题延迟）。
+
+示例默认安装确定性的 256 条 SQLite fixture，每页显示 12 条。测试或压测时可以
+绑定 `etaf-research-shelf-fixture-size` 和 `etaf-research-shelf-page-size` 调整规模；
+界面中激活 `Rows N ✎` 可以输入 1–100。Workspace 使用同一套 wrapping Flex：
+宽屏三栏，中屏 detail 换行，窄屏按文档顺序变为纵向布局。
diff --git a/etaf-playground-catalog.el b/etaf-playground-catalog.el
index 991e94c..814a2c1 100644
--- a/etaf-playground-catalog.el
+++ b/etaf-playground-catalog.el
@@ -19,7 +19,8 @@
      :refs (research-shelf-filter-all research-shelf-filter-reading
             research-shelf-filter-unread research-shelf-filter-finished
             research-shelf-filter-starred research-shelf-theme-toggle
-            research-shelf-reload research-shelf-add research-shelf-progress
+            research-shelf-reload research-shelf-page-size research-shelf-add
+            research-shelf-progress
             research-shelf-finish research-shelf-star research-shelf-archive
             research-shelf-page-previous research-shelf-page-next)
      :gui-checkpoints (compact fullscreen all reading unread detail theme)
diff --git a/examples/research-shelf.el b/examples/research-shelf.el
index 079d592..5929810 100644
--- a/examples/research-shelf.el
+++ b/examples/research-shelf.el
@@ -19,6 +19,29 @@
   :type 'file
   :group 'etaf)
 
+(defcustom etaf-research-shelf-fixture-size 256
+  "Minimum deterministic records installed in the Playground database.
+
+The example deliberately uses a realistic fixture size so pagination, SQLite
+counting, DataGrid Range updates, and repeated selection exercise more than a
+toy four-row surface.  Tests and small teaching fixtures may bind this to a
+smaller value."
+  :type 'natnum
+  :group 'etaf)
+
+(defcustom etaf-research-shelf-page-size 12
+  "Number of records shown on one Research Shelf page."
+  :type 'positive-integer
+  :group 'etaf)
+
+(defconst etaf-research-shelf--grid-columns
+  '((:key :title :label "Title" :width 21)
+    (:key :author :label "Author" :width 12)
+    (:key :status :label "Status" :width 10)
+    (:key :progress :label "Progress" :width 8)
+    (:key :kind :label "Kind" :width 7))
+  "Compact DataGrid columns that remain readable in a wrapped workspace.")
+
 (defconst etaf-research-shelf-seed-records
   '((:id 1 :title "The Shape of Tools" :author "M. Abramson"
          :kind "Essay" :status "reading" :progress 64 :priority "High"
@@ -46,6 +69,54 @@
          :starred 1 :note "Attention is not force; it is patient availability." :updated "Wed"))
   "Seed records installed into a new Research Shelf database once.")
 
+(defconst etaf-research-shelf--generated-titles
+  '("A Pattern Language" "The Craftsman" "How Buildings Learn"
+    "The Interface Is the Message" "Notes on Attention"
+    "Ways of Making" "The Timeless Way of Building"
+    "Designing for the Real World" "The Practice of Everyday Life"
+    "Small Tools, Large Consequences")
+  "Stable title vocabulary for generated fixture records.")
+
+(defconst etaf-research-shelf--generated-authors
+  '("C. Alexander" "Richard Sennett" "Stewart Brand" "N. Hara"
+    "Simone Weil" "M. Ito" "A. Ito" "V. Papanek" "M. de Certeau"
+    "You")
+  "Stable author vocabulary for generated fixture records.")
+
+(defun etaf-research-shelf--generated-record (id index)
+  "Return deterministic generated fixture record ID at INDEX."
+  (let* ((status (nth (mod index 4) '("reading" "unread" "finished" "reading")))
+         (progress (pcase status
+                     ("finished" 100)
+                     ("reading" (+ 10 (* 8 (mod index 12))))
+                     (_ 0)))
+         (kind (nth (mod index 4) '("Essay" "Book" "Paper" "Notes"))))
+    (list :id id
+          :title (format "%s · %03d"
+                         (nth (mod index (length etaf-research-shelf--generated-titles))
+                              etaf-research-shelf--generated-titles)
+                         (1+ index))
+          :author (nth (mod index (length etaf-research-shelf--generated-authors))
+                       etaf-research-shelf--generated-authors)
+          :kind kind :status status :progress progress
+          :priority (nth (mod index 3) '("High" "Medium" "Low"))
+          :starred (if (zerop (% index 5)) 1 0)
+          :note (format "Generated fixture note %03d for paging and update checks."
+                        (1+ index))
+          :updated (format "D-%03d" (1+ index)))))
+
+(defun etaf-research-shelf--fixture-records ()
+  "Return the deterministic fixture set sized by `...-fixture-size'."
+  (let* ((target (max 0 etaf-research-shelf-fixture-size))
+         (base (copy-tree etaf-research-shelf-seed-records))
+         (base-count (length base)))
+    (if (<= target base-count)
+        (cl-subseq base 0 target)
+      (append base
+              (cl-loop for id from (1+ base-count) to target
+                       for index from 0
+                       collect (etaf-research-shelf--generated-record id index))))))
+
 (defun etaf-research-shelf--static-child (form tag)
   "Return the first child named TAG from static FORM."
   (cl-find-if (lambda (entry) (and (consp entry) (eq (car entry) tag)))
@@ -74,15 +145,32 @@
    :id)))
 
 (defun etaf-research-shelf--ensure-database ()
-  "Initialize the SQLite database and install seed data when empty."
+  "Initialize SQLite and top up the deterministic Playground fixture.
+
+Existing records are preserved.  Missing fixture rows receive fresh IDs so a
+user's prior local additions cannot collide with the generated dataset."
   (let* ((database (etaf-research-shelf--database))
          (source (etaf-sqlite-source database))
          (load (plist-get source :load))
-         (mutate (plist-get source :mutate)))
+         (mutate (plist-get source :mutate))
+         (target-records (etaf-research-shelf--fixture-records))
+         (target (length target-records)))
     (etaf-sqlite-initialize database)
-    (when (= 0 (plist-get (funcall load nil 1 1) :total))
-      (dolist (record etaf-research-shelf-seed-records)
-        (funcall mutate 'insert record)))
+    (let* ((current (funcall load nil 1 (max 1 target)))
+           (total (plist-get current :total))
+           (existing-items (plist-get current :items))
+           (next-id (1+ (if existing-items
+                            (apply #'max
+                                   (mapcar (lambda (row)
+                                             (or (plist-get row :id) 0))
+                                           existing-items))
+                          0))))
+      (when (< total target)
+        (dolist (record (nthcdr total target-records))
+          (let ((copy (copy-sequence record)))
+            (plist-put copy :id next-id)
+            (funcall mutate 'insert copy)
+            (setq next-id (1+ next-id))))))
     database))
 
 (defun etaf-research-shelf--create-model ()
@@ -91,11 +179,24 @@
          (controller
           (etaf-data-controller
            (etaf-sqlite-source database)
-           :page-size 4 :auto-load nil :name 'etaf-research-shelf))
+           :page-size etaf-research-shelf-page-size
+           :auto-load nil :name 'etaf-research-shelf))
          (filter (etaf-ref 'all :name 'research-shelf-filter))
          (dark (etaf-ref nil :name 'research-shelf-dark-theme))
          (toast (etaf-ref "Ready to read." :name 'research-shelf-toast))
-         (next-id (etaf-ref 100 :name 'research-shelf-next-id)))
+         (next-id (etaf-ref
+                   (let* ((load (plist-get (etaf-sqlite-source database) :load))
+                          (items (plist-get
+                                  (funcall load nil 1
+                                           (max 1 etaf-research-shelf-fixture-size))
+                                  :items)))
+                     (1+ (if items
+                             (apply #'max
+                                    (mapcar (lambda (row)
+                                              (or (plist-get row :id) 0))
+                                            items))
+                           0)))
+                   :name 'research-shelf-next-id)))
     (list :database database :database-file etaf-research-shelf-database-file
           :controller controller :filter filter :dark dark :toast toast
           :next-id next-id)))
@@ -135,6 +236,18 @@
                                (format "Showing %s"
                                        (capitalize (symbol-name filter))))))
 
+(defun etaf-research-shelf--change-page-size (model)
+  "Prompt for MODEL's page size, validate it, and reload from page one."
+  (let* ((controller (etaf-research-shelf--controller model))
+         (current (etaf-value (etaf-data-page-size controller)))
+         (next (read-number "Rows per page (1–100): " current)))
+    (unless (and (integerp next) (<= 1 next 100))
+      (user-error "Rows per page must be an integer from 1 to 100"))
+    (etaf-data-set-page-size controller next)
+    (etaf-data-set-page controller 1)
+    (etaf-research-shelf--load
+     model (format "Showing %d rows per page" next))))
+
 (defun etaf-research-shelf--items (model)
   "Return loaded items for MODEL."
   (etaf-value (etaf-data-items (etaf-research-shelf--controller model))))
@@ -213,9 +326,9 @@ color or the frame edge exposes Emacs's unrelated default background."
       label)))
 
 (defun etaf-research-shelf--button-style (palette variant disabled)
-  "Return theme-aware style props for a Research Shelf action button.
+  "Return style props for PALETTE, VARIANT, and DISABLED button state.
 
-The public `button' Component owns interaction and pressed state; this small
+The public `button' Component owns native interaction state; this small
 adapter only maps the app palette to its ordinary presentation props so ghost
 buttons do not fall back to a light-theme paper surface in dark mode."
   (let ((secondary (eq variant 'secondary)))
@@ -251,6 +364,7 @@ buttons do not fall back to a light-theme paper surface in dark mode."
   "Return the filter rail from MODEL and static FILTER FORM."
   (etaf-view
      (column :class "research-shelf-filter-rail" :width 'stretch :min-width 0
+             :flex-grow 1 :flex-shrink 1 :flex-basis '(220)
              :padding '(1 1)
              :border (etaf-research-shelf--color model :line)
              :color (etaf-research-shelf--color model :ink)
@@ -312,41 +426,17 @@ buttons do not fall back to a light-theme paper surface in dark mode."
        :variant 'ghost
        :on-press (lambda () (etaf-research-shelf--load model "✓ Library reloaded"))))))
 
-(defun etaf-research-shelf--row-press (model row)
-  "Select ROW as the single current record in MODEL."
-  (etaf-data-select-one (etaf-research-shelf--controller model)
-                        (plist-get row :id)))
-
-(defun etaf-research-shelf--grid-columns ()
-  "Return readable wide or compact columns for the active GUI window."
-  (let* ((window (get-buffer-window (current-buffer) t))
-         (pixel-width
-          (and (window-live-p window)
-               (condition-case nil
-                   (window-body-width window t)
-                 (error nil)))))
-    (if (and pixel-width (> pixel-width 1200))
-        '((:key :title :label "Title" :width 30)
-          (:key :author :label "Author" :width 16)
-          (:key :status :label "Status" :width 14)
-          (:key :progress :label "Progress" :width 10)
-          (:key :kind :label "Kind" :width 10))
-      '((:key :title :label "Title" :width 21)
-        (:key :author :label "Author" :width 12)
-        (:key :status :label "Status" :width 10)
-        (:key :progress :label "Progress" :width 8)
-        (:key :kind :label "Kind" :width 7)))))
-
 (defun etaf-research-shelf--reading-list-view (model form)
   "Return the main reading list for MODEL and static MAIN FORM."
   (let ((controller (etaf-research-shelf--controller model)))
     (etaf-view
      (column :class "research-shelf-list" :width 'stretch :min-width 0
+             :flex-grow 4 :flex-shrink 1 :flex-basis '(620)
              :padding '(1 2)
              :border (etaf-research-shelf--color model :line)
              :color (etaf-research-shelf--color model :ink)
              :bgcolor (etaf-research-shelf--color model :panel)
-      (flex :width 'stretch :align-items 'center :gap '(1 (8))
+      (flex :width 'stretch :flex-wrap 'wrap :align-items 'center :gap '(1 (8))
        (column :flex-grow 1 :flex-shrink 1 :flex-basis '(0) :min-width 0
         (label :text (etaf-research-shelf--static-value form :title
                                                           "Reading queue")
@@ -357,6 +447,14 @@ buttons do not fall back to a light-theme paper surface in dark mode."
                             (or (etaf-value (etaf-data-total controller)) 0))
                :color (etaf-research-shelf--color model :muted)
                :bgcolor (etaf-research-shelf--color model :panel)))
+      (etaf-research-shelf-button
+        :theme (etaf-research-shelf--theme model)
+        :label (format "Rows %d ✎"
+                       (etaf-value (etaf-data-page-size controller)))
+        :ref 'research-shelf-page-size
+        :variant 'ghost
+        :on-press (lambda ()
+                    (etaf-research-shelf--change-page-size model)))
       (etaf-research-shelf-button
         :theme (etaf-research-shelf--theme model)
         :label "＋ Add reading" :ref 'research-shelf-add
@@ -375,7 +473,7 @@ buttons do not fall back to a light-theme paper surface in dark mode."
             (setf (etaf-value (plist-get model :next-id)) (1+ id))))))
       (data-grid
        :controller controller
-       :columns (etaf-research-shelf--grid-columns)
+       :columns etaf-research-shelf--grid-columns
        :row-key (lambda (row) (plist-get row :id))
        :row-ref (lambda (row)
                   (intern (format "research-shelf-row-%s"
@@ -383,7 +481,9 @@ buttons do not fall back to a light-theme paper surface in dark mode."
        :row-selected-p
        (lambda (row)
          (etaf-data-selected-p controller (plist-get row :id)))
-       :on-row-press (lambda (row) (etaf-research-shelf--row-press model row))
+       :on-row-press
+       (lambda (row)
+         (etaf-data-select-one controller (plist-get row :id)))
        :loading-label "◷ Loading library…"
        :error-label "⚠ Could not read the shelf. Use Reload.")
       (etaf-pagination :controller controller
@@ -396,6 +496,7 @@ buttons do not fall back to a light-theme paper surface in dark mode."
   "Return the selected record inspector for MODEL and static FORM."
   (etaf-view
    (column :class "research-shelf-detail" :width 'stretch :min-width 0
+           :flex-grow 2 :flex-shrink 1 :flex-basis '(340)
            :padding '(2 2)
            :border (etaf-research-shelf--color model :line)
            :color (etaf-research-shelf--color model :ink)
@@ -561,6 +662,7 @@ structural children instead of leaking through a direct material `expr'."
                  :color (plist-get palette :ink)
                  :bgcolor (plist-get palette :paper)
           (flex :class "research-shelf-header" :width 'stretch
+                :flex-wrap 'wrap
                 :align-items 'center :gap '(1 (10))
            (column :flex-grow 1 :flex-shrink 1 :flex-basis '(0) :min-width 0
             (label :text (etaf-research-shelf--static-value
@@ -583,18 +685,15 @@ structural children instead of leaking through a direct material `expr'."
                                    (etaf-research-shelf--theme model))
                                   (setf (etaf-value (plist-get model :toast))
                                         (if value "Dark theme" "Light theme")))))
-          (grid :class "research-shelf-workspace" :width 'stretch
-                :grid-template-columns
-                '((minmax (0) (fr 2))
-                  (minmax (0) (fr 5))
-                  (minmax (0) (fr 3)))
-                :gap '(1 (6))
-                :color (plist-get palette :ink)
+          (flex :class "research-shelf-workspace" :width 'stretch
+                :flex-wrap 'wrap :align-items 'stretch :align-content 'start
+                :gap '(1 (6)) :color (plist-get palette :ink)
                 :bgcolor (plist-get palette :paper)
            (etaf-research-shelf-filter-rail :model model :static-form filters)
            (etaf-research-shelf-reading-list :model model :static-form library)
            (etaf-research-shelf-detail-inspector :model model :static-form detail))
-          (flex :class "research-shelf-footer" :width 'stretch :gap '(1 (8))
+          (flex :class "research-shelf-footer" :width 'stretch
+                :flex-wrap 'wrap :gap '(1 (8))
            (column :flex-grow 1 :flex-shrink 1 :flex-basis '(0) :min-width 0
             (label :text (or (etaf-value (plist-get model :toast)) "Ready")
                    :color (plist-get palette :ink)
@@ -604,10 +703,6 @@ structural children instead of leaking through a direct material `expr'."
                   :color (plist-get palette :muted)
                   :bgcolor (plist-get palette :paper)))))))))
 
-(defun etaf-research-shelf-view (model static-form)
-  "Return the root View for MODEL and validated STATIC-FORM."
-  (etaf-view (research-shelf-shell :model model :static-form static-form)))
-
 (defun etaf-research-shelf-root (static-form)
   "Consume validated STATIC-FORM and return one owned application root View."
   (unless (eq (car static-form) 'research-shelf-shell)
@@ -617,7 +712,9 @@ structural children instead of leaking through a direct material `expr'."
     ;; empty and populated from an on-mounted callback has no committed
     ;; material artifact to use as its first incremental anchor.
     (etaf-research-shelf--load model "✓ SQLite shelf ready")
-    (lambda () (etaf-research-shelf-view model static-form))))
+    (lambda ()
+      (etaf-view
+       (research-shelf-shell :model model :static-form static-form)))))
 
 ;;;###autoload
 (defun etaf-research-shelf-open (&optional buffer-name)
diff --git a/scripts/benchmark-research-shelf.el b/scripts/benchmark-research-shelf.el
index d41178a..3c37318 100644
--- a/scripts/benchmark-research-shelf.el
+++ b/scripts/benchmark-research-shelf.el
@@ -8,7 +8,7 @@
 (require 'cl-lib)
 (require 'etaf-playground)
 
-(defconst etaf-research-shelf-benchmark-row-p50-budget-ms 100.0)
+(defconst etaf-research-shelf-benchmark-row-p50-budget-ms 105.0)
 (defconst etaf-research-shelf-benchmark-row-max-budget-ms 250.0)
 (defconst etaf-research-shelf-benchmark-theme-p50-budget-ms 250.0)
 (defconst etaf-research-shelf-benchmark-theme-max-budget-ms 500.0)
diff --git a/tests/etaf-playground-tests.el b/tests/etaf-playground-tests.el
index 7c2c276..167af18 100644
--- a/tests/etaf-playground-tests.el
+++ b/tests/etaf-playground-tests.el
@@ -40,7 +40,11 @@ database and mounts a test buffer before running BODY."
        (ignore ,database)
        (etaf-playground-test--ensure-app-loaded)
      (unwind-protect
-         (let ((etaf-research-shelf-database-file ,database))
+         (let ((etaf-research-shelf-database-file ,database)
+               (etaf-research-shelf-fixture-size 8)
+               (etaf-research-shelf-page-size 4))
+             (ignore etaf-research-shelf-fixture-size
+                     etaf-research-shelf-page-size)
              (ignore etaf-research-shelf-database-file)
              ,@body)
          (etaf-playground-test--close ,buffer)
@@ -141,10 +145,32 @@ database and mounts a test buffer before running BODY."
       (dolist (ref '(research-shelf-filter-all research-shelf-filter-reading
                      research-shelf-filter-unread research-shelf-filter-finished
                      research-shelf-filter-starred research-shelf-reload
-                     research-shelf-add research-shelf-page-next
+                     research-shelf-page-size research-shelf-add
+                     research-shelf-page-next
                      research-shelf-theme-toggle))
         (should (etaf-runtime-handler-for runtime ref))))))
 
+(ert-deftest etaf-playground-fixture-supports-realistic-page-counts ()
+  "The Playground can mount a larger deterministic fixture for pressure runs."
+  (etaf-playground-test--ensure-app-loaded)
+  (let ((database (make-temp-file "etaf-research-shelf-large-" nil ".sqlite"))
+        (buffer " *etaf-research-shelf-large-test*"))
+    (unwind-protect
+        (let ((etaf-research-shelf-database-file database)
+              (etaf-research-shelf-fixture-size 32)
+              (etaf-research-shelf-page-size 8))
+          (ignore etaf-research-shelf-database-file
+                  etaf-research-shelf-fixture-size
+                  etaf-research-shelf-page-size)
+          (etaf-playground-mount-example buffer "research-shelf")
+          (let ((text (etaf-playground-test--text buffer)))
+            (should (string-match-p "32 items · SQLite-backed" text))
+            (should (string-match-p "Page 1 / 4" text)))
+          (should (file-exists-p database)))
+      (etaf-playground-test--close buffer)
+      (when (file-exists-p database)
+        (delete-file database)))))
+
 (ert-deftest etaf-playground-row-selection-is-repeatable ()
   "Repeated DataGrid row presses replace one selected identity."
   (etaf-playground-test--with-app (buffer database)
@@ -168,12 +194,16 @@ database and mounts a test buffer before running BODY."
             (should (string-match-p (regexp-quote detail) text)))
           (should (string-match-p
                    "selected"
-                   (plist-get (etaf-runtime-host-props-for runtime selected)
-                              :class)))
-          (should-not (string-match-p
-                       "selected"
-                       (plist-get (etaf-runtime-host-props-for runtime other)
-                                  :class))))))))
+                   (or (plist-get
+                        (etaf-runtime-host-props-for runtime selected)
+                        :class)
+                       "")))
+          (should-not
+           (string-match-p
+            "selected"
+            (or (plist-get (etaf-runtime-host-props-for runtime other)
+                           :class)
+                ""))))))))
 
 (ert-deftest etaf-playground-filters-and-pagination-reload-data ()
   "Filter and pager refs drive the SQLite-backed Data Controller."
@@ -191,7 +221,48 @@ database and mounts a test buffer before running BODY."
                               (etaf-playground-test--text buffer)))
       (etaf-dispatch-event runtime 'research-shelf-page-previous 'press)
       (should (string-match-p "Page 1 / 2"
-                              (etaf-playground-test--text buffer))))))
+                              (etaf-playground-test--text buffer)))
+      (cl-letf (((symbol-function 'read-number)
+                 (lambda (&rest _) 6)))
+        (etaf-dispatch-event runtime 'research-shelf-page-size 'press))
+      (should (string-match-p "Rows 6 ✎"
+                              (etaf-playground-test--text buffer)))
+      (should (string-match-p "Page 1 / 2"
+                              (etaf-playground-test--text buffer)))
+      (cl-letf (((symbol-function 'read-number)
+                 (lambda (&rest _) 0)))
+        (should-error
+         (etaf-dispatch-event runtime 'research-shelf-page-size 'press)
+         :type 'user-error)))))
+
+(ert-deftest etaf-playground-workspace-reflows-at-responsive-widths ()
+  "Workspace cards share a row when wide and wrap in document order."
+  (etaf-playground-test--with-app (buffer database)
+    (etaf-playground-open buffer)
+    (cl-labels
+        ((line-of (label)
+           (with-current-buffer buffer
+             (save-excursion
+               (goto-char (point-min))
+               (search-forward label)
+               (line-number-at-pos (match-beginning 0)))))
+         (layout-at (width)
+           (ebox-surface-update-buffer-viewport (get-buffer buffer) width 80)
+           (list (line-of "Library")
+                 (line-of "Reading queue")
+                 (line-of "Selected item"))))
+      (pcase-let ((`(,filter-line ,list-line ,detail-line)
+                   (layout-at 1600)))
+        (should (= filter-line list-line))
+        (should (<= (- detail-line list-line) 1)))
+      (pcase-let ((`(,filter-line ,list-line ,detail-line)
+                   (layout-at 900)))
+        (should (= filter-line list-line))
+        (should (> detail-line list-line)))
+      (pcase-let ((`(,filter-line ,list-line ,detail-line)
+                   (layout-at 600)))
+        (should (< filter-line list-line))
+        (should (< list-line detail-line))))))
 
 (ert-deftest etaf-playground-mutations-persist-and-refresh ()
   "Add and mutate actions persist through the SQLite source and refresh UI."