diff --git a/public/admin/config.yml b/public/admin/config.yml
index 95760e7..454b7fa 100644
--- a/public/admin/config.yml
+++ b/public/admin/config.yml
@@ -143,6 +143,73 @@ collections:
   - name: site_pages
     label: 页面文案
     files:
+      - name: pages
+        label: 瞬间 / 书架 标题下的说明
+        file: content/site/pages.yaml
+        format: yaml
+        hint: 这两页大标题下面那一行字，文字与样式都在这里改
+        fields:
+          - label: 瞬间页
+            name: moments
+            widget: object
+            required: false
+            fields:
+              - label: 说明文字
+                name: note
+                widget: object
+                required: false
+                hint: 支持 markdown 与排版类（字体/颜色）
+                fields:
+                  - { label: 中文, name: zh, widget: markdown, required: false }
+                  - { label: English, name: en, widget: markdown, required: false }
+              - label: 样式
+                name: style
+                widget: object
+                required: false
+                hint: 留空用全站默认；越界值会被自动夹取（不会破版）
+                fields:
+                  - { label: 字号（px，11–16）, name: size, widget: number, required: false, value_type: int, min: 11, max: 16 }
+                  - label: 颜色
+                    name: color
+                    widget: select
+                    required: false
+                    hint: 只开放灰阶层级，避免正文被染色
+                    options: [ink-1, ink-2, ink-3, ink-4]
+                  - label: 字体
+                    name: font
+                    widget: select
+                    required: false
+                    options: [font-sans, font-serif, font-kai, font-huiwen, font-kuaile, font-xiaowei, font-huangyou, font-mashanzheng, font-liujianmaocao, font-smiley, font-neoxihei]
+          - label: 书架页
+            name: books
+            widget: object
+            required: false
+            fields:
+              - label: 说明文字
+                name: note
+                widget: object
+                required: false
+                hint: 支持 markdown 与排版类（字体/颜色）
+                fields:
+                  - { label: 中文, name: zh, widget: markdown, required: false }
+                  - { label: English, name: en, widget: markdown, required: false }
+              - label: 样式
+                name: style
+                widget: object
+                required: false
+                hint: 留空用全站默认；越界值会被自动夹取（不会破版）
+                fields:
+                  - { label: 字号（px，11–16）, name: size, widget: number, required: false, value_type: int, min: 11, max: 16 }
+                  - label: 颜色
+                    name: color
+                    widget: select
+                    required: false
+                    options: [ink-1, ink-2, ink-3, ink-4]
+                  - label: 字体
+                    name: font
+                    widget: select
+                    required: false
+                    options: [font-sans, font-serif, font-kai, font-huiwen, font-kuaile, font-xiaowei, font-huangyou, font-mashanzheng, font-liujianmaocao, font-smiley, font-neoxihei]
       - name: home
         label: 主页设置
         file: content/site/home.yaml
@@ -544,11 +611,19 @@ collections:
             fields:
               - { label: 中文, name: zh, widget: string }
               - { label: English, name: en, widget: string }
-          - label: 叙述（链接前）
+          - label: 叙述（推荐改这里）
+            name: story
+            widget: object
+            required: false
+            hint: '整段叙述写成一个字段即可（markdown + 排版类），链接直接写在句子里：[本站源码](https://git.wait4x.online/wait4x/blog) —— 这样就不用再分"链接前/链接后"。留空时才会退回下面的旧字段拼接'
+            fields:
+              - { label: 中文, name: zh, widget: markdown, required: false }
+              - { label: English, name: en, widget: markdown, required: false }
+          - label: 叙述（旧：链接前）
             name: blurb
             widget: object
             required: false
-            hint: 富文本（markdown + 排版类），渲染在仓库链接之前
+            hint: 'legacy：仅当上面的「叙述」为空时才使用（历史字段，为把仓库链接夹在中间而拆成两半）'
             fields:
               - { label: 中文, name: zh, widget: string, required: false }
               - { label: 英文, name: en, widget: string, required: false }
diff --git a/src/pages/heatmap-preview.astro b/src/pages/heatmap-preview.astro
index 5652bad..4430433 100644
--- a/src/pages/heatmap-preview.astro
+++ b/src/pages/heatmap-preview.astro
@@ -1,10 +1,16 @@
 ---
 /**
- * 热力图动效方案预览 v2（Phase 5j）——用户看过 v1 五案后觉得不够，要求「类似贪吃蛇」的
- * 方案并再深入设计 4–6 个。本页给 6 个更深入的方案（F–K），v1 的 A–E 已下线。
+ * 热力图动效方案 v3（Phase 5j）——用户选定方向「F+J」，但要求贪吃蛇能**循环**，
+ * 并希望再看几个新变体。故本页给四个蛇家族方案 + J 柱状图参考：
  *
- * 设计红线（六案都守）：灰阶骨架、accent 只做高亮不做数据编码（数据仍由 ink 四档承载）、
- * prefers-reduced-motion 一律静态、零第三方依赖、离开视口即停（省电）。
+ *   F1 循环贪吃蛇（GitHub README 蛇的循环逻辑）
+ *   F2 生长蛇（吃得越多身体越长）
+ *   F3 双蛇对开（两头同时吃，交汇于年中）
+ *   FJ 蛇 + 月度柱联动（用户要的 F+J 组合）
+ *   J  月度柱状图（单独保留作参考）
+ *
+ * 设计红线：accent 只做高亮不参与数据编码（数据密度仍由 ink 四档承载）、
+ * prefers-reduced-motion 静态化、离开视口即停、零第三方依赖。
  */
 import BaseLayout from '../layouts/BaseLayout.astro';
 import HeatGrid from '../components/geek/HeatGrid.astro';
@@ -14,7 +20,7 @@ const { weeks, total } = await loadHeatmap();
 const days: HeatDay[] = weeks.flat();
 const buildTime = new Date().toISOString().slice(0, 10);
 
-/* ── 连续贡献（本地计算，口径：以最后一个有贡献的日子为终点往回数）── */
+/* 连续贡献（本地计算，口径：以最后一个有贡献的日子为终点往回数） */
 const countOf = new Map(days.map((d) => [d.date, d.count]));
 const isoOf = (d: Date) => d.toISOString().slice(0, 10);
 const lastActive = [...days].reverse().find((d) => d.count > 0)?.date ?? '';
@@ -34,9 +40,8 @@ for (const d of days) {
   run = d.count > 0 ? run + 1 : 0;
   if (run > longest) longest = run;
 }
-const bestDay = days.reduce((a, b) => (b.count > a.count ? b : a), days[0]);
 
-/* ── 月度聚合（J 方案用）── */
+/* 月度聚合（J / FJ 用） */
 const byMonth = new Map<string, number>();
 for (const d of days) {
   const key = d.date.slice(0, 7);
@@ -44,102 +49,103 @@ for (const d of days) {
 }
 const months = [...byMonth.entries()].sort(([a], [b]) => a.localeCompare(b));
 const maxMonth = Math.max(...months.map(([, v]) => v));
-
-/* ── 最后活跃日的坐标（H 涟漪终点起点）── */
-const lastActiveIdx = days.findLastIndex((d) => d.date === lastActive);
-const lastActiveCol = Math.floor(lastActiveIdx / 7);
-const lastActiveRow = lastActiveIdx % 7;
-
-const stats = { total, current, longest, best: bestDay?.count ?? 0, bestDate: bestDay?.date ?? '' };
-const dataForClient = { cells: days.map((d) => d.count), weeks: weeks.length };
+const activeDays = days.filter((d) => d.count > 0).length;
+const stats = { total, current, longest, activeDays };
 ---
 
-<BaseLayout title="热力图动效方案 v2 · wait4x" description="六个更深入的热力图动效方案">
-  <h1 class="pv-title">热力图：六个更深入的方案</h1>
+<BaseLayout title="热力图动效方案 v3 · wait4x" description="贪吃蛇的四个循环变体 + 月度柱状图">
+  <h1 class="pv-title">热力图：蛇的四个变体</h1>
   <p class="pv-note">
-    同一份真实数据（近一年 <strong>{stats.total}</strong> 次贡献 · 当前连续
-    <strong>{stats.current}</strong> 天 · 最长 {stats.longest} 天 · 单日最高 {stats.best} 次），
-    数据更新于 {buildTime}。
+    按你的选择做成 <strong>F + J</strong> 方向，并让蛇<strong>循环</strong>爬（学 GitHub README 蛇的
+    节奏：吃完一轮 → 停顿 → 清空 → 再来）。真实数据：近一年 <strong>{stats.total}</strong> 次贡献 ·
+    {stats.activeDays} 天有贡献 · 当前连续 {stats.current} 天 · 数据更新于 {buildTime}。
     <br />
-    上一版的五个方案已按你的反馈下线；这一版六个都往「有生命、有叙事」的方向推。
-    <strong>回字母告诉我选哪个</strong>（也可以说「F 但慢一点」「F + J 组合」）。
+    <strong>回字母告诉我选哪个</strong>（F1 / F2 / F3 / FJ / J），也可以说「FJ 但循环慢一点」。
   </p>
 
   <nav class="pv-switch" aria-label="方案跳转">
-    <a href="#hf" class="pv-chip">F · 贪吃蛇</a>
-    <a href="#hg" class="pv-chip">G · 心跳呼吸</a>
-    <a href="#hh" class="pv-chip">H · 雨滴涟漪</a>
-    <a href="#hi" class="pv-chip">I · 3D 地形</a>
-    <a href="#hj" class="pv-chip">J · 周冠军柱</a>
-    <a href="#hk" class="pv-chip">K · 显微镜</a>
+    <a href="#f1" class="pv-chip">F1 · 循环贪吃蛇</a>
+    <a href="#f2" class="pv-chip">F2 · 生长蛇</a>
+    <a href="#f3" class="pv-chip">F3 · 双蛇对开</a>
+    <a href="#fj" class="pv-chip">FJ · 蛇 + 柱联动</a>
+    <a href="#j" class="pv-chip">J · 月度柱</a>
   </nav>
 
-  <!-- ═══════════ F · 贪吃蛇 ═══════════ -->
-  <section id="hf" class="pv-sec">
+  <!-- ══════ F1 · 循环贪吃蛇 ══════ -->
+  <section id="f1" class="pv-sec">
     <header class="pv-head">
-      <span class="pv-tag mono">F</span>
-      <h2>贪吃蛇</h2>
-      <p class="pv-pros">一条蛇沿着贡献格蛇形爬过：吃到有贡献的格子就把它们点亮并"长"一点，空格直接穿过。
-        <b>优点</b>最有生命感、天然表达"这一年被一点点吃掉"；<b>代价</b>是持续动画（离开视口即暂停）。</p>
+      <span class="pv-tag mono">F1</span>
+      <h2>循环贪吃蛇</h2>
+      <p class="pv-pros">蛇沿格子蛇形爬一年，吃到有贡献的日子就点亮；爬到尽头停一拍、清空、重新开始，
+        <b>无限循环</b>。身体保持 6 格长度（GitHub README 蛇手感）。</p>
     </header>
-    <div class="hm-wrap" data-snake>
-      <HeatGrid weeks={weeks} variant="snake" />
+    <div class="hm-wrap" data-snake data-body={6}>
+      <HeatGrid weeks={weeks} variant="f1" />
     </div>
-    <p class="hm-read mono"><span data-snake-read>准备出发…</span> · <button class="hm-btn" type="button" data-snake-replay>重新开始</button></p>
+    <p class="hm-read mono"><span data-snake-read>准备出发…</span> · 第 <span data-snake-loop>1</span> 轮 ·
+      <button class="hm-btn" type="button" data-snake-toggle>暂停</button></p>
   </section>
 
-  <!-- ═══════════ G · 心跳呼吸 ═══════════ -->
-  <section id="hg" class="pv-sec">
+  <!-- ══════ F2 · 生长蛇 ══════ -->
+  <section id="f2" class="pv-sec">
     <header class="pv-head">
-      <span class="pv-tag mono">G</span>
-      <h2>心跳呼吸</h2>
-      <p class="pv-pros">每格按当日贡献量呼吸：越忙的日子跳得越快、越亮，静下来时整片缓慢起伏。
-        <b>优点</b>像一张"活的"心电图，无需交互；<b>代价</b>持续动画（纯 CSS，合成层，很省）。</p>
+      <span class="pv-tag mono">F2</span>
+      <h2>生长蛇</h2>
+      <p class="pv-pros">每吃到一天就长一节（最长 26 节），前半程是细蛇、后半程拖成长尾，吃完循环重置。
+        <b>优点</b>"积累"的隐喻最强；<b>代价</b>尾长时略挡格子。</p>
     </header>
-    <div class="hm-wrap" data-breath>
-      <HeatGrid weeks={weeks} variant="breath" />
+    <div class="hm-wrap" data-snake data-body={3} data-grow={26}>
+      <HeatGrid weeks={weeks} variant="f2" />
     </div>
+    <p class="hm-read mono"><span data-snake-read>准备出发…</span> · 蛇长 <span data-snake-len>3</span> 节</p>
   </section>
 
-  <!-- ═══════════ H · 雨滴涟漪 ═══════════ -->
-  <section id="hh" class="pv-sec">
+  <!-- ══════ F3 · 双蛇对开 ══════ -->
+  <section id="f3" class="pv-sec">
     <header class="pv-head">
-      <span class="pv-tag mono">H</span>
-      <h2>雨滴涟漪</h2>
-      <p class="pv-pros">从"最后一次贡献"那一格出发，涟漪一圈圈向外扩散，扫过的格子闪一下再落定。
-        <b>优点</b>叙事清晰（现在 → 过去）、只播一次；<b>代价</b>纯装饰。</p>
+      <span class="pv-tag mono">F3</span>
+      <h2>双蛇对开</h2>
+      <p class="pv-pros">两条蛇分别从最早与最新一头出发对向而吃，在年中附近交汇，吃完一起循环。
+        <b>优点</b>更有戏剧性、时间感双向；<b>代价</b>两条同时动，注意力会被分走。</p>
     </header>
-    <div class="hm-wrap" data-ripple>
-      <HeatGrid weeks={weeks} variant="ripple" />
+    <div class="hm-wrap" data-snake data-body={5} data-dual="1">
+      <HeatGrid weeks={weeks} variant="f3" />
     </div>
-    <p class="hm-read mono"><button class="hm-btn" type="button" data-ripple-replay>再看一次涟漪</button> · 起点 {lastActive}</p>
+    <p class="hm-read mono"><span data-snake-read>准备出发…</span></p>
   </section>
 
-  <!-- ═══════════ I · 3D 地形 ═══════════ -->
-  <section id="hi" class="pv-sec">
+  <!-- ══════ FJ · 蛇 + 月柱联动 ══════ -->
+  <section id="fj" class="pv-sec">
     <header class="pv-head">
-      <span class="pv-tag mono">I</span>
-      <h2>3D 地形</h2>
-      <p class="pv-pros">把贡献量当"海拔"：忙的日子凸起来，整块网格随鼠标轻轻倾斜，像俯瞰一年的地貌。
-        <b>优点</b>一眼看出密集区、视觉独特；<b>代价</b>倾斜会略降可读性。</p>
+      <span class="pv-tag mono">FJ</span>
+      <h2>蛇 + 月度柱联动 <span class="pv-rec">你的选择方向</span></h2>
+      <p class="pv-pros">蛇每爬进一个月，对应的柱子就同步升起并高亮；爬到年末时十二根柱子全部立起，
+        然后蛇回到起点、柱子清零、再来一轮。<b>优点</b>格子与柱状图互相解释，信息与动感兼得。</p>
     </header>
-    <div class="hm-3d" data-terrain>
-      <div class="hm-3d-inner">
-        <HeatGrid weeks={weeks} variant="terrain" />
-      </div>
+    <div class="hm-wrap" data-snake data-body={6} data-bars-link="1">
+      <HeatGrid weeks={weeks} variant="fj" />
     </div>
+    <ul class="hm-bars" data-months>
+      {months.map(([m, v], i) => (
+        <li>
+          <span class="hm-bar-btn"><span class="hm-bar-fill" data-month-idx={i} style={`--h:${Math.round((v / maxMonth) * 100)}%`} /></span>
+          <span class="hm-bar-label mono">{m.slice(5)}</span>
+        </li>
+      ))}
+    </ul>
+    <p class="hm-read mono"><span data-snake-read>准备出发…</span></p>
   </section>
 
-  <!-- ═══════════ J · 周冠军柱 ═══════════ -->
-  <section id="hj" class="pv-sec">
+  <!-- ══════ J · 月度柱（单独参考）══════ -->
+  <section id="j" class="pv-sec">
     <header class="pv-head">
       <span class="pv-tag mono">J</span>
-      <h2>周冠军柱</h2>
-      <p class="pv-pros">网格下方按月长出一排柱子，进视口时逐根升起；指针移到柱子上，对应那些格子同时亮起。
-        <b>优点</b>把"哪几个月最忙"讲清楚、信息量大；<b>代价</b>多一层图表，页面变高。</p>
+      <h2>月度柱状图</h2>
+      <p class="pv-pros">不带动效时的样子：进视口逐根升起，指针移到柱子上，对应月份的格子同时高亮。
+        <b>可单独用，也可像 FJ 那样与蛇联动。</b></p>
     </header>
     <div class="hm-wrap" data-bars>
-      <HeatGrid weeks={weeks} variant="bars" />
+      <HeatGrid weeks={weeks} variant="j" />
     </div>
     <ul class="hm-bars" data-bars-chart>
       {months.map(([m, v]) => (
@@ -153,240 +159,192 @@ const dataForClient = { cells: days.map((d) => d.count), weeks: weeks.length };
     </ul>
   </section>
 
-  <!-- ═══════════ K · 显微镜 ═══════════ -->
-  <section id="hk" class="pv-sec">
-    <header class="pv-head">
-      <span class="pv-tag mono">K</span>
-      <h2>显微镜</h2>
-      <p class="pv-pros">指针所在处浮起一枚圆镜，把周围 5×5 的格子放大显示，并标出当天日期与次数。
-        <b>优点</b>小格子也读得清、趣味强；<b>代价</b>触屏需点按。</p>
-    </header>
-    <div class="hm-wrap hm-lens-wrap" data-lens>
-      <HeatGrid weeks={weeks} variant="lens" />
-      <span class="hm-lens" data-lens-glass hidden></span>
-    </div>
-    <p class="hm-read mono" data-lens-read>把指针移到任意格子上</p>
-  </section>
+  <p class="pv-foot mono">数据口径：GitHub GraphQL 贡献日历，构建期快照（{buildTime}）。"减少动态效果"下全部静态；离开视口自动暂停。</p>
 
-  <p class="pv-foot mono">数据口径：GitHub GraphQL 贡献日历，构建期快照（{buildTime}）。"减少动态效果"下六案全部静态。</p>
-
-  <script is:inline type="application/json" id="hm-data" set:html={JSON.stringify(dataForClient)} />
-  <span hidden data-ripple-origin={`${lastActiveCol},${lastActiveRow}`}></span>
+  <span hidden data-months-map={JSON.stringify(months.map(([m]) => m))} data-weeks={weeks.length}></span>
 </BaseLayout>
 
 <script>
   const reduce = matchMedia('(prefers-reduced-motion: reduce)').matches;
-  const raw = document.getElementById('hm-data')?.textContent ?? '{"cells":[],"weeks":0}';
-  const DATA = JSON.parse(raw) as { cells: number[]; weeks: number };
-  const cellsAll = () => [...document.querySelectorAll<HTMLElement>('.hg-c')];
+  const weeksN = Number(document.querySelector<HTMLElement>('[data-weeks]')?.dataset.weeks ?? 53);
+  const monthKeys: string[] = JSON.parse(
+    document.querySelector<HTMLElement>('[data-months-map]')?.dataset.monthsMap ?? '[]',
+  );
 
-  /** 离开视口即停：省电，也避免滚动时 CPU 抖动 */
-  const whenVisible = (el: Element, onIn: () => void, onOut?: () => void) => {
-    const io = new IntersectionObserver(
-      (entries) => {
-        for (const e of entries) (e.isIntersecting ? onIn : onOut)?.();
-      },
-      { threshold: 0.15 },
-    );
-    io.observe(el);
-    return io;
-  };
-
-  /* ══════ F · 贪吃蛇 ══════ */
-  for (const wrap of document.querySelectorAll<HTMLElement>('[data-snake]')) {
-    const cells = [...wrap.querySelectorAll<HTMLElement>('.hg-c')];
-    const readEl = document.querySelector<HTMLElement>('[data-snake-read]');
-    // 蛇形路径：按列走，奇数列自下而上（与 GitHub 贡献蛇同构）
-    const path: number[] = [];
-    for (let c = 0; c < DATA.weeks; c++) {
+  /** 蛇形路径：按列推进，奇数列自下而上（与 GitHub README 蛇同构） */
+  const buildPath = () => {
+    const p: number[] = [];
+    for (let c = 0; c < weeksN; c++) {
       const rows = [0, 1, 2, 3, 4, 5, 6];
       if (c % 2 === 1) rows.reverse();
-      for (const r of rows) path.push(c * 7 + r);
+      for (const r of rows) p.push(c * 7 + r);
     }
-    let step = 0;
-    let timer = 0;
+    return p;
+  };
+  const PATH = buildPath();
+
+  for (const wrap of document.querySelectorAll<HTMLElement>('[data-snake]')) {
+    const cells = [...wrap.querySelectorAll<HTMLElement>('.hg-c')];
+    const readEl = wrap.parentElement?.querySelector<HTMLElement>('[data-snake-read]');
+    const loopEl = wrap.parentElement?.querySelector<HTMLElement>('[data-snake-loop]');
+    const lenEl = wrap.parentElement?.querySelector<HTMLElement>('[data-snake-len]');
+    const toggle = wrap.parentElement?.querySelector<HTMLButtonElement>('[data-snake-toggle]');
+    const barsEl = wrap.parentElement?.querySelector<HTMLElement>('[data-months]');
+    const bars = barsEl ? [...barsEl.querySelectorAll<HTMLElement>('[data-month-idx]')] : [];
+
+    const baseBody = Number(wrap.dataset.body ?? 6);
+    const growTo = Number(wrap.dataset.grow ?? 0);
+    const dual = wrap.dataset.dual === '1';
+    const barsLink = wrap.dataset.barsLink === '1';
+
+    let body = baseBody;
     let eaten = 0;
-    const reset = () => {
-      step = 0;
-      eaten = 0;
-      cells.forEach((c) => c.classList.remove('snake-head', 'snake-eaten', 'snake-passed'));
-      if (readEl) readEl.textContent = '准备出发…';
+    let loopNo = 1;
+    let timer = 0;
+    let paused = false;
+    // 双蛇：两条独立游标，反向推进
+    const cursors = dual ? [0, PATH.length - 1] : [0];
+    const dirs = dual ? [1, -1] : [1];
+    const trails: number[][] = cursors.map(() => []);
+
+    const paint = () => {
+      cells.forEach((c) => c.classList.remove('snake-head', 'snake-body', 'snake-eaten'));
+      trails.forEach((t) => t.forEach((i) => cells[i]?.classList.add('snake-body')));
+      cursors.forEach((cur, si) => {
+        const cell = cells[PATH[cur]];
+        if (cell) cell.classList.add('snake-head');
+        const e = trails[si];
+        if (e) e[e.length - 1] = PATH[cur];
+        void cur;
+      });
     };
-    const tick = () => {
-      const idx = path[step];
-      cells.forEach((c) => c.classList.remove('snake-head'));
-      const cell = cells[idx];
-      if (!cell) return;
-      cell.classList.add('snake-head');
-      // 爬过即留下淡色轨迹：真实数据里 371 格只有 ~51 天有贡献，
-      // 若只在有贡献的格子给反馈，蛇大半程看起来是"空跑"。
-      cell.classList.add('snake-passed');
-      const count = Number(cell.dataset.count ?? 0);
-      if (count > 0) {
-        cell.classList.add('snake-eaten');
-        eaten++;
-        if (readEl) readEl.textContent = `${cell.dataset.date} · 吃到 ${count} 次（累计 ${eaten} 天）`;
-      }
-      step++;
-      if (step >= path.length) {
-        if (readEl) readEl.textContent = `整年爬完：走过 ${path.length} 格，吃到 ${eaten} 天`;
+
+    const reset = (full: boolean) => {
+      eaten = 0;
+      body = baseBody;
+      cursors.forEach((_, i) => (cursors[i] = i === 0 ? 0 : PATH.length - 1));
+      trails.forEach((t) => (t.length = 0));
+      cells.forEach((c) => c.classList.remove('snake-head', 'snake-body', 'snake-eaten'));
+      if (full) bars.forEach((b) => b.classList.remove('on'));
+      if (lenEl) lenEl.textContent = String(body);
+      if (loopEl) loopEl.textContent = String(loopNo);
+    };
+
+    const step = () => {
+      let moved = false;
+      cursors.forEach((cur, si) => {
+        const idx = PATH[cur];
+        if (idx === undefined) return;
+        moved = true;
+        const cell = cells[idx];
+        if (!cell) return;
+        // 轨迹队列：保持 body 长度
+        const trail = trails[si];
+        trail.push(idx);
+        if (trail.length > body) {
+          const dropped = trail.shift();
+          cells[dropped ?? -1]?.classList.remove('snake-body');
+        }
+        cells.forEach((c) => c.classList.remove('snake-head'));
+        cursors.forEach((c2) => cells[PATH[c2]]?.classList.add('snake-head'));
+        cells[idx].classList.add('snake-body');
+
+        const count = Number(cell.dataset.count ?? 0);
+        if (count > 0) {
+          cell.classList.add('snake-eaten');
+          eaten++;
+          if (growTo) body = Math.min(growTo, body + 1);
+          if (readEl)
+            readEl.textContent = `${cell.dataset.date} · 吃到 ${count} 次（累计 ${eaten} 天）`;
+        }
+        // 月份联动：柱子按当前列所属月份点亮
+        if (barsLink && bars.length) {
+          const col = Math.floor(idx / 7);
+          const date = cell.dataset.date ?? '';
+          const mi = monthKeys.indexOf(date.slice(0, 7));
+          if (mi >= 0) bars.slice(0, mi + 1).forEach((b) => b.classList.add('on'));
+        }
+        if (lenEl) lenEl.textContent = String(body);
+        // 推进游标
+        const next = cur + dirs[si];
+        cursors[si] = next;
+        if (next < 0 || next >= PATH.length) cursors[si] = -1 as number;
+      });
+      // 全部游标到端点 → 一轮结束
+      if (!moved || cursors.every((c) => c < 0)) {
         clearInterval(timer);
         timer = 0;
+        if (readEl) readEl.textContent = `第 ${loopNo} 轮完成：吃到 ${eaten} 天`;
+        loopNo++;
+        setTimeout(() => {
+          reset(true);
+          if (!paused) start();
+        }, 900);
       }
+      void paint;
     };
+
     const start = () => {
-      reset();
-      if (reduce) {
-        cells.forEach((c) => {
-          c.classList.add('snake-passed');
-          if (Number(c.dataset.count ?? 0) > 0) c.classList.add('snake-eaten');
-        });
-        if (readEl) readEl.textContent = '已按减少动态效果静态呈现';
-        return;
-      }
-      if (timer) return;
-      timer = window.setInterval(tick, 30);
+      if (timer || paused) return;
+      reset(false);
+      timer = window.setInterval(step, 26);
     };
-    whenVisible(
-      wrap,
-      () => {
-        if (!timer) start();
-      },
-      () => {
-        if (timer) {
-          clearInterval(timer);
-          timer = 0;
-        }
-      },
-    );
-    document.querySelector('[data-snake-replay]')?.addEventListener('click', () => {
+
+    const stop = () => {
       if (timer) clearInterval(timer);
       timer = 0;
-      start();
-    });
-  }
-
-  /* ══════ G · 心跳呼吸（纯 CSS 驱动，只按数据写变量）══════ */
-  for (const wrap of document.querySelectorAll<HTMLElement>('[data-breath]')) {
-    const max = Math.max(...DATA.cells, 1);
-    for (const cell of wrap.querySelectorAll<HTMLElement>('.hg-c')) {
-      const n = Number(cell.dataset.count ?? 0);
-      if (n <= 0) continue;
-      // 越忙跳得越快（时长 3.4s → 1.2s），幅度略随强度增大
-      const dur = 3.4 - (n / max) * 2.2;
-      cell.style.setProperty('--breath', `${dur.toFixed(2)}s`);
-      cell.classList.add('hg-breath');
-    }
-  }
-
-  /* ══════ H · 雨滴涟漪 ══════ */
-  for (const wrap of document.querySelectorAll<HTMLElement>('[data-ripple]')) {
-    const origin = document.querySelector('[data-ripple-origin]')?.getAttribute('data-ripple-origin') ?? '0,0';
-    const [oc, or] = origin.split(',').map(Number);
-    const play = () => {
-      for (const cell of wrap.querySelectorAll<HTMLElement>('.hg-c')) {
-        const c = Number(cell.dataset.c ?? 0);
-        const r = Number(cell.dataset.r ?? 0);
-        // 以"最后一次贡献"为圆心，按列/行距离给错峰延迟
-        const dist = Math.hypot(c - oc, (r - or) * 1.6);
-        cell.style.setProperty('--wave', `${Math.round(dist * 26)}ms`);
-      }
-      wrap.classList.remove('play');
-      void wrap.offsetWidth; // 强制回流，让动画重播
-      wrap.classList.add('play');
     };
-    whenVisible(wrap, () => {
-      if (!reduce) play();
-    });
-    document.querySelector('[data-ripple-replay]')?.addEventListener('click', () => {
-      if (!reduce) play();
-    });
-  }
 
-  /* ══════ I · 3D 地形 ══════ */
-  for (const wrap of document.querySelectorAll<HTMLElement>('[data-terrain]')) {
-    const max = Math.max(...DATA.cells, 1);
-    for (const cell of wrap.querySelectorAll<HTMLElement>('.hg-c')) {
-      const n = Number(cell.dataset.count ?? 0);
-      cell.style.setProperty('--z', `${((n / max) * 14).toFixed(1)}px`);
-      if (n > 0) cell.classList.add('hg-raise');
+    toggle?.addEventListener('click', () => {
+      paused = !paused;
+      toggle.textContent = paused ? '继续' : '暂停';
+      if (paused) stop();
+      else start();
+    });
+
+    if (reduce) {
+      // 减少动态：直接展示终态（所有有贡献的格子点亮 + 柱子立起）
+      cells.forEach((c) => {
+        if (Number(c.dataset.count ?? 0) > 0) c.classList.add('snake-eaten');
+      });
+      bars.forEach((b) => b.classList.add('on'));
+      if (readEl) readEl.textContent = '已按"减少动态效果"静态呈现';
+    } else {
+      new IntersectionObserver(
+        (entries) => {
+          for (const e of entries) {
+            if (e.isIntersecting) start();
+            else stop();
+          }
+        },
+        { threshold: 0.15 },
+      ).observe(wrap);
     }
-    if (reduce) continue;
-    wrap.addEventListener('pointermove', (e) => {
-      const r = wrap.getBoundingClientRect();
-      const dx = (e.clientX - r.left) / r.width - 0.5;
-      const dy = (e.clientY - r.top) / r.height - 0.5;
-      wrap.style.setProperty('--rx', `${(-dy * 10).toFixed(2)}deg`);
-      wrap.style.setProperty('--ry', `${(dx * 12).toFixed(2)}deg`);
-    });
-    wrap.addEventListener('pointerleave', () => {
-      wrap.style.setProperty('--rx', '0deg');
-      wrap.style.setProperty('--ry', '0deg');
-    });
   }
 
-  /* ══════ J · 周冠军柱 ══════ */
-  for (const chart of document.querySelectorAll<HTMLElement>('[data-bars-chart]')) {
-    whenVisible(chart, () => chart.classList.add('grow'));
+  /* J：单独的柱状图（进视口升起 + hover 联动） */
+  const chart = document.querySelector<HTMLElement>('[data-bars-chart]');
+  if (chart) {
+    new IntersectionObserver(
+      (entries) => {
+        for (const e of entries) if (e.isIntersecting) e.target.classList.add('grow');
+      },
+      { threshold: 0.2 },
+    ).observe(chart);
     const grid = document.querySelector<HTMLElement>('[data-bars]');
     for (const btn of chart.querySelectorAll<HTMLElement>('[data-month]')) {
       const m = btn.dataset.month ?? '';
-      btn.addEventListener('pointerenter', () => {
-        grid?.querySelectorAll<HTMLElement>('.hg-c').forEach((c) => {
-          c.classList.toggle('hg-month', (c.dataset.date ?? '').startsWith(m));
-        });
-      });
-      btn.addEventListener('pointerleave', () => {
-        grid?.querySelectorAll<HTMLElement>('.hg-c').forEach((c) => c.classList.remove('hg-month'));
-      });
-      btn.addEventListener('focus', () => btn.dispatchEvent(new Event('pointerenter')));
-      btn.addEventListener('blur', () => btn.dispatchEvent(new Event('pointerleave')));
+      const on = () =>
+        grid?.querySelectorAll<HTMLElement>('.hg-c').forEach((c) =>
+          c.classList.toggle('hg-month', (c.dataset.date ?? '').startsWith(m)),
+        );
+      const off = () => grid?.querySelectorAll<HTMLElement>('.hg-c').forEach((c) => c.classList.remove('hg-month'));
+      btn.addEventListener('pointerenter', on);
+      btn.addEventListener('pointerleave', off);
+      btn.addEventListener('focus', on);
+      btn.addEventListener('blur', off);
     }
   }
-
-  /* ══════ K · 显微镜 ══════ */
-  for (const wrap of document.querySelectorAll<HTMLElement>('[data-lens]')) {
-    const glass = wrap.querySelector<HTMLElement>('[data-lens-glass]');
-    const read = document.querySelector<HTMLElement>('[data-lens-read]');
-    const cells = [...wrap.querySelectorAll<HTMLElement>('.hg-c')];
-    const show = (cell: HTMLElement) => {
-      const c = Number(cell.dataset.c ?? 0);
-      const r = Number(cell.dataset.r ?? 0);
-      if (!glass) return;
-      glass.hidden = false;
-      // 5×5 邻域放大：用 CSS 变量把每格的"档位"喂给镜内的 25 个小格
-      let mini = '';
-      for (let dr = -2; dr <= 2; dr++) {
-        for (let dc = -2; dc <= 2; dc++) {
-          const idx = (c + dc) * 7 + (r + dr);
-          const n = data(idx);
-          mini += `<i style="--v:${Math.min(n, 8)}"></i>`;
-        }
-      }
-      glass.innerHTML = `<span class="hm-lens-grid">${mini}</span><span class="hm-lens-tip mono">${cell.dataset.date} · ${cell.dataset.count} 次</span>`;
-      const box = wrap.getBoundingClientRect();
-      const cb = cell.getBoundingClientRect();
-      glass.style.setProperty('--lx', `${cb.left - box.left + cb.width / 2}px`);
-      glass.style.setProperty('--ly', `${cb.top - box.top + cb.height / 2}px`);
-      if (read) read.textContent = `${cell.dataset.date} · ${cell.dataset.count} 次`;
-      cells.forEach((x) => x.classList.remove('hg-focus'));
-      cell.classList.add('hg-focus');
-      void r;
-    };
-    const data = (idx: number) => (idx >= 0 && idx < DATA.cells.length ? DATA.cells[idx] : 0);
-    wrap.addEventListener('pointermove', (e) => {
-      const t = (e.target as HTMLElement).closest<HTMLElement>('.hg-c');
-      if (t) show(t);
-    });
-    wrap.addEventListener('pointerleave', () => {
-      if (glass) glass.hidden = true;
-      cells.forEach((x) => x.classList.remove('hg-focus'));
-    });
-    wrap.addEventListener('click', (e) => {
-      const t = (e.target as HTMLElement).closest<HTMLElement>('.hg-c');
-      if (t) show(t);
-    });
-  }
 </script>
 
 <style>
@@ -406,6 +364,7 @@ const dataForClient = { cells: days.map((d) => d.count), weeks: weeks.length };
   .pv-sec { margin-top: var(--space-6); scroll-margin-top: 56px; }
   .pv-head { border-top: 1px solid var(--line); padding-top: var(--space-3); }
   .pv-tag { display: inline-block; font-size: 11px; color: var(--ink-4); border: 1px solid var(--line); border-radius: 4px; padding: 0 5px; }
+  .pv-rec { font-size: 11px; color: var(--accent); border: 1px solid color-mix(in oklab, var(--accent) 40%, var(--line)); border-radius: 4px; padding: 0 5px; margin-left: 6px; font-family: var(--font-mono); }
   .pv-head h2 { font-size: 20px; color: var(--ink-1); margin: var(--space-1) 0; }
   .pv-pros { font-size: 13px; color: var(--ink-3); line-height: 1.7; max-width: var(--measure); margin: 0 0 var(--space-3); }
   .pv-pros b { color: var(--ink-2); }
@@ -418,99 +377,42 @@ const dataForClient = { cells: days.map((d) => d.count), weeks: weeks.length };
   }
   .hm-btn:hover { border-color: var(--accent); }
 
-  /* ── F 蛇：头 + 吃过 ── */
+  /* 蛇：头 / 身 / 吃过 */
   :global(.snake-head) {
     outline: 2px solid var(--accent);
     outline-offset: 1px;
-    z-index: 1;
+    z-index: 2;
     position: relative;
   }
-  :global(.snake-passed) {
-    background: color-mix(in oklab, var(--accent) 16%, transparent);
-    transition: background 220ms var(--ease);
+  :global(.snake-body) {
+    background: color-mix(in oklab, var(--accent) 32%, transparent) !important;
   }
   :global(.snake-eaten) {
     background: var(--accent) !important;
     box-shadow: 0 0 0 1px color-mix(in oklab, var(--accent) 45%, transparent);
-    transform: scale(1.12);
-    transition: background 180ms var(--ease), transform 180ms var(--ease);
+    transition: background 180ms var(--ease);
   }
 
-  /* ── G 呼吸 ── */
-  :global(.hg-breath) { animation: hmBreath var(--breath, 2.6s) ease-in-out infinite; }
-  @keyframes hmBreath {
-    0%, 100% { opacity: 0.55; transform: scale(0.94); }
-    50% { opacity: 1; transform: scale(1.06); }
-  }
-
-  /* ── H 涟漪 ── */
-  .play :global(.hg-c) { animation: hmWave 700ms ease-out var(--wave, 0ms) both; }
-  @keyframes hmWave {
-    0% { transform: scale(0.7); filter: brightness(1.6); }
-    60% { transform: scale(1.12); }
-    100% { transform: none; filter: none; }
-  }
-
-  /* ── I 3D 地形 ── */
-  .hm-3d { perspective: 900px; padding: var(--space-3) 0; overflow-x: auto; }
-  .hm-3d-inner {
-    transform: rotateX(var(--rx, 6deg)) rotateY(var(--ry, 0deg));
-    transform-style: preserve-3d;
-    transition: transform 160ms var(--ease);
-    will-change: transform;
-  }
-  :global(.hg-raise) {
-    transform: translateZ(var(--z, 0px));
-    box-shadow: 0 1px 3px rgb(0 0 0 / 0.18);
-  }
-
-  /* ── J 周冠军柱 ── */
+  /* 月度柱 */
   .hm-bars {
     display: flex; align-items: flex-end; gap: 6px; list-style: none;
-    padding: 0; margin: var(--space-3) 0 0; height: 92px;
+    padding: 0; margin: var(--space-2) 0 0; height: 84px;
   }
   .hm-bars li { display: flex; flex-direction: column; align-items: center; gap: 4px; flex: 1; height: 100%; justify-content: flex-end; }
-  .hm-bar-btn {
-    width: 100%; height: 100%; display: flex; align-items: flex-end;
-    background: none; border: 0; padding: 0; cursor: pointer;
-  }
+  .hm-bar-btn { width: 100%; height: 100%; display: flex; align-items: flex-end; background: none; border: 0; padding: 0; cursor: pointer; }
   .hm-bar-fill {
     display: block; width: 100%; height: 0;
     background: var(--ink-4); border-radius: 2px 2px 0 0;
-    transition: height 520ms cubic-bezier(0.22, 0.8, 0.3, 1), background 160ms var(--ease);
+    transition: height 420ms cubic-bezier(0.22, 0.8, 0.3, 1), background 160ms var(--ease);
   }
   .grow .hm-bar-fill { height: var(--h, 0%); }
-  .hm-bar-btn:hover .hm-bar-fill, .hm-bar-btn:focus-visible .hm-bar-fill { background: var(--accent); }
+  /* FJ：蛇爬到该月时柱子升起（由 JS 加 .on） */
+  .hm-bar-fill.on { height: var(--h, 0%); background: var(--accent); }
+  .hm-bar-btn:hover .hm-bar-fill { background: var(--accent); }
   .hm-bar-label { font-size: 10.5px; color: var(--ink-4); }
   :global(.hg-month) { background: var(--accent) !important; }
 
-  /* ── K 显微镜 ── */
-  .hm-lens-wrap { position: relative; }
-  .hm-lens {
-    position: absolute; left: var(--lx, 0); top: var(--ly, 0); translate: -50% -50%;
-    width: 132px; height: 132px; border-radius: 50%;
-    border: 1px solid color-mix(in oklab, var(--accent) 40%, var(--line));
-    background: color-mix(in oklab, var(--bg) 92%, transparent);
-    box-shadow: 0 8px 24px rgb(0 0 0 / 0.18);
-    backdrop-filter: blur(3px);
-    pointer-events: none; z-index: 4;
-    display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 4px;
-  }
-  .hm-lens-grid {
-    display: grid; grid-template-columns: repeat(5, 14px); grid-template-rows: repeat(5, 14px); gap: 3px;
-  }
-  .hm-lens-grid i {
-    width: 14px; height: 14px; border-radius: 2px;
-    background: color-mix(in oklab, var(--ink-1) calc(var(--v) * 11%), transparent);
-    border: 1px solid color-mix(in oklab, var(--line) 80%, transparent);
-  }
-  .hm-lens-tip { font-size: 10px; color: var(--ink-3); }
-  :global(.hg-focus) { outline: 2px solid var(--accent); outline-offset: 1px; }
-
   @media (prefers-reduced-motion: reduce) {
-    :global(.hg-breath) { animation: none; opacity: 1; }
-    .play :global(.hg-c) { animation: none; }
-    .hm-3d-inner { transform: none !important; transition: none; }
-    .grow .hm-bar-fill { transition: none; }
+    .hm-bar-fill { transition: none; }
   }
 </style>