diff --git a/CONTEXT.md b/CONTEXT.md
new file mode 100644
index 0000000..622cb23
--- /dev/null
+++ b/CONTEXT.md
@@ -0,0 +1,37 @@
+# SpineWallpaper（网页壁纸作品）
+
+一份已发布的 Wallpaper Engine 网页壁纸，以及围绕它的资源分层与验证约定。这个上下文只关心"一档壁纸由什么组成、怎么被打包和切换"。
+
+## Language
+
+**作品（Project）**：
+一个 Wallpaper Engine 打包单元，即 `dist/` 整个目录；`project.json` 是它的清单，`index.html` 是它的入口。
+_Avoid_: 工程、站点、应用
+
+**游戏（Game）**：
+壁纸所出自的作品名（`崩坏：星穹铁道`），资源分层的第一级，也是目录结构的第一层。
+_Avoid_: 来源、IP
+
+**壁纸（Wallpaper）**：
+用户可在 WE 属性里切换的一档壁纸（`昔涟立绘`、`「成为昨日的明天」`）；它的显示名就是它的目录名，可以改。
+_Avoid_: 预设、选项、preset（当指"这一档"本身时）
+
+**预设（Preset）**：
+一档壁纸的配置实体，落盘为该壁纸目录下的 `preset.js`，声明这一档要用哪些资源、以什么参数播放。一档壁纸对应且仅对应一个预设。
+_Avoid_: 配置、profile、manifest
+
+**预设 id**：
+预设的稳定标识（`xilian`、`kv37`），必须与 WE 属性值一致，永不随显示名变化——已发布作品的用户设置靠它维系。
+_Avoid_: slug、键名、代号
+
+**音源（AudioSource）**：
+一首可作背景音乐的曲子。每首曲子归属且只归属一档壁纸；WE 的音源列表是所有壁纸音源声明的并集。
+_Avoid_: BGM、曲目、音频文件
+
+**视口（Viewport）**：
+交给 Spine 播放器的世界坐标系矩形，决定构图。它以等比"contain"方式映射到画布：单轴贴边、另一轴会多露出世界，因此负 padding 的裁切只在目标比例下成立。
+_Avoid_: 相机、取景框、裁剪区
+
+**对拍（AB capture）**：
+同一壁纸、同一分辨率、同一动画相位下的改动前后像素比对。噪声底约 0.7/255；低于 1 视为无差异。
+_Avoid_: 截图测试、视觉回归
diff --git a/dist/assets/audios/pv37.mp3 b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/audios/pv37.mp3
similarity index 100%
rename from dist/assets/audios/pv37.mp3
rename to dist/assets/崩坏：星穹铁道/「成为昨日的明天」/audios/pv37.mp3
diff --git a/dist/assets/effects/kv37.json b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/effects/kv37.json
similarity index 100%
rename from dist/assets/effects/kv37.json
rename to dist/assets/崩坏：星穹铁道/「成为昨日的明天」/effects/kv37.json
diff --git a/dist/assets/images/kv37.atlas b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37.atlas
similarity index 100%
rename from dist/assets/images/kv37.atlas
rename to dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37.atlas
diff --git a/dist/assets/images/kv37.png b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37.png
similarity index 100%
rename from dist/assets/images/kv37.png
rename to dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37.png
diff --git a/dist/assets/images/kv37_2.png b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37_2.png
similarity index 100%
rename from dist/assets/images/kv37_2.png
rename to dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37_2.png
diff --git a/dist/assets/images/kv37_3.png b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37_3.png
similarity index 100%
rename from dist/assets/images/kv37_3.png
rename to dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37_3.png
diff --git a/dist/assets/images/kv37_4.png b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37_4.png
similarity index 100%
rename from dist/assets/images/kv37_4.png
rename to dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37_4.png
diff --git a/dist/assets/images/kv37_5.png b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37_5.png
similarity index 100%
rename from dist/assets/images/kv37_5.png
rename to dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37_5.png
diff --git a/dist/assets/images/kv37_xilian.png b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37_xilian.png
similarity index 100%
rename from dist/assets/images/kv37_xilian.png
rename to dist/assets/崩坏：星穹铁道/「成为昨日的明天」/images/kv37_xilian.png
diff --git a/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/preset.js b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/preset.js
new file mode 100644
index 0000000..3c26e71
--- /dev/null
+++ b/dist/assets/崩坏：星穹铁道/「成为昨日的明天」/preset.js
@@ -0,0 +1,34 @@
+// 「成为昨日的明天」—— 官方 3.7 版本专题展示页
+// 这份预设自带全部资源，路径由 import.meta.url 从本文件位置推导，
+// 因此整个目录可以整体搬走或改名，而不用改这里的任何一行。
+
+const base = new URL("./", import.meta.url);
+const asset = (path) => new URL(path, base).href;
+
+export default {
+  id: "kv37", // 与 project.json 中 combo 选项的 value 一致，勿改
+  name: "「成为昨日的明天」",
+  game: "崩坏：星穹铁道",
+
+  backgroundImage: asset("./images/kv37_xilian.png"),
+
+  spineConfig: {
+    jsonUrl: asset("./effects/kv37.json"),
+    atlasUrl: asset("./images/kv37.atlas"),
+    animation: "animation",
+    viewport: {
+      x: -1215,
+      y: -410,
+      width: 2048,
+      height: 1024,
+    },
+  },
+
+  audioOptions: {
+    source: asset("./audios/pv37.mp3"),
+    volume: 0.5,
+  },
+
+  // 本壁纸可选的音源（第 6 步会接进 project.json 的 bgm 属性）
+  audioChoices: [{ id: "pv37", name: "版本 PV", source: asset("./audios/pv37.mp3") }],
+};
diff --git a/dist/assets/audios/「再度和你」.flac b/dist/assets/崩坏：星穹铁道/昔涟立绘/audios/「再度和你」.flac
similarity index 100%
rename from dist/assets/audios/「再度和你」.flac
rename to dist/assets/崩坏：星穹铁道/昔涟立绘/audios/「再度和你」.flac
diff --git a/dist/assets/audios/昔涟.flac b/dist/assets/崩坏：星穹铁道/昔涟立绘/audios/昔涟.flac
similarity index 100%
rename from dist/assets/audios/昔涟.flac
rename to dist/assets/崩坏：星穹铁道/昔涟立绘/audios/昔涟.flac
diff --git a/dist/assets/effects/xilian.json b/dist/assets/崩坏：星穹铁道/昔涟立绘/effects/xilian.json
similarity index 100%
rename from dist/assets/effects/xilian.json
rename to dist/assets/崩坏：星穹铁道/昔涟立绘/effects/xilian.json
diff --git a/dist/assets/images/ava.jpg b/dist/assets/崩坏：星穹铁道/昔涟立绘/images/ava.jpg
similarity index 100%
rename from dist/assets/images/ava.jpg
rename to dist/assets/崩坏：星穹铁道/昔涟立绘/images/ava.jpg
diff --git a/dist/assets/images/xilian.atlas b/dist/assets/崩坏：星穹铁道/昔涟立绘/images/xilian.atlas
similarity index 100%
rename from dist/assets/images/xilian.atlas
rename to dist/assets/崩坏：星穹铁道/昔涟立绘/images/xilian.atlas
diff --git a/dist/assets/images/xilian.png b/dist/assets/崩坏：星穹铁道/昔涟立绘/images/xilian.png
similarity index 100%
rename from dist/assets/images/xilian.png
rename to dist/assets/崩坏：星穹铁道/昔涟立绘/images/xilian.png
diff --git a/dist/assets/images/xilian_2.png b/dist/assets/崩坏：星穹铁道/昔涟立绘/images/xilian_2.png
similarity index 100%
rename from dist/assets/images/xilian_2.png
rename to dist/assets/崩坏：星穹铁道/昔涟立绘/images/xilian_2.png
diff --git a/dist/assets/images/xilian_3.png b/dist/assets/崩坏：星穹铁道/昔涟立绘/images/xilian_3.png
similarity index 100%
rename from dist/assets/images/xilian_3.png
rename to dist/assets/崩坏：星穹铁道/昔涟立绘/images/xilian_3.png
diff --git a/dist/assets/崩坏：星穹铁道/昔涟立绘/preset.js b/dist/assets/崩坏：星穹铁道/昔涟立绘/preset.js
new file mode 100644
index 0000000..17a9e9e
--- /dev/null
+++ b/dist/assets/崩坏：星穹铁道/昔涟立绘/preset.js
@@ -0,0 +1,37 @@
+// 昔涟立绘 —— 官方昔涟动态立绘
+// 这份预设自带全部资源，路径由 import.meta.url 从本文件位置推导，
+// 因此整个目录可以整体搬走或改名，而不用改这里的任何一行。
+
+const base = new URL("./", import.meta.url);
+const asset = (path) => new URL(path, base).href;
+
+export default {
+  id: "xilian", // 与 project.json 中 combo 选项的 value 一致，勿改
+  name: "昔涟立绘",
+  game: "崩坏：星穹铁道",
+
+  backgroundImage: asset("./images/ava.jpg"),
+
+  spineConfig: {
+    jsonUrl: asset("./effects/xilian.json"),
+    atlasUrl: asset("./images/xilian.atlas"),
+    animation: "idle",
+    viewport: {
+      padLeft: "-25%",
+      padRight: "-28%",
+      padTop: "-30%",
+      padBottom: "-23%",
+    },
+  },
+
+  audioOptions: {
+    source: asset("./audios/「再度和你」.flac"),
+    volume: 0.5,
+  },
+
+  // 本壁纸可选的音源（第 6 步会接进 project.json 的 bgm 属性）
+  audioChoices: [
+    { id: "zaiduheni", name: "再度和你", source: asset("./audios/「再度和你」.flac") },
+    { id: "xilian", name: "昔涟", source: asset("./audios/昔涟.flac") },
+  ],
+};
diff --git a/dist/scripts/index.js b/dist/scripts/index.js
index 06cdf73..556ce68 100644
--- a/dist/scripts/index.js
+++ b/dist/scripts/index.js
@@ -1,87 +1,87 @@
-import PresetStore from "./preset-store.js";
-
-import PresetController from "./preset-controller.js";
-import BackgroundController from "./background-controller.js";
-import SpineController from "./spine-controller.js";
-import AudioController from "./audio-controller.js";
-
-let presetController = new PresetController(PresetStore);
-
-let { backgroundImage, spineConfig, audioOptions } =
-  presetController.set("xilian");
-
-let backgroundController = new BackgroundController(backgroundImage);
-let spineController = new SpineController("spine-container", spineConfig);
-let audioController = new AudioController("background-music", audioOptions);
-
-let currentAudioSource = "";
-let currentAudioVolume = 0;
-
-window.addEventListener("load", function () {
-  backgroundController.setImage();
-  spineController.create();
-  audioController.play();
-});
-
-window.addEventListener("resize", () => {
-  spineController.adjustCanvas();
-});
-
-window.wallpaperRegisterListener = {
-  applyGeneralProperties: function (properties) {
-    if (properties.fps) {
-      // wallpaperSettings.fps = properties.fps;
-    }
-  },
-  applyUserProperties: function (properties) {
-    if (properties.preset) {
-      const preset = properties.preset.value;
-      let { backgroundImage, spineConfig, audioOptions } =
-        presetController.set(preset);
-      backgroundController.changeImage(backgroundImage);
-      spineController.changeConfig(spineConfig);
-      audioController.changeOptions(audioOptions);
-    }
-    if (properties.audio_file) {
-      const audio_file = properties.audio_file.value;
-      currentAudioSource = audio_file;
-      audioController.changeSource(audio_file);
-    }
-    if (properties.audio_volume) {
-      const audio_volume = properties.audio_volume.value;
-      currentAudioVolume = audio_volume;
-      audioController.changeVolume(audio_volume);
-    }
-  },
-};
-
-window.wallpaperPropertyListener = {
-  applyGeneralProperties: function (properties) {
-    if (properties.fps) {
-      // wallpaperSettings.fps = properties.fps;
-    }
-  },
-  applyUserProperties: function (properties) {
-    if (properties.preset) {
-      const preset = properties.preset.value;
-      let { backgroundImage, spineConfig, audioOptions } = presetController.set(
-        preset,
-        currentAudioSource,
-        currentAudioVolume
-      );
-      backgroundController.changeImage(backgroundImage);
-      spineController.changeConfig(spineConfig);
-      audioController.changeOptions(audioOptions);
-    }
-    if (properties.audio_file) {
-      const audio_file = properties.audio_file.value;
-      currentAudioSource = audio_file;
-      audioController.changeSource(audio_file);
-    }
-    if (properties.audio_volume) {
-      const audio_volume = properties.audio_volume.value;
-      currentAudioVolume = audio_volume;
-      audioController.changeVolume(audio_volume);
-    }
-  },
-};
+import Presets from "./presets.js";
+
+import PresetController from "./preset-controller.js";
+import BackgroundController from "./background-controller.js";
+import SpineController from "./spine-controller.js";
+import AudioController from "./audio-controller.js";
+
+let presetController = new PresetController(Presets);
+
+let { backgroundImage, spineConfig, audioOptions } =
+  presetController.set("xilian");
+
+let backgroundController = new BackgroundController(backgroundImage);
+let spineController = new SpineController("spine-container", spineConfig);
+let audioController = new AudioController("background-music", audioOptions);
+
+let currentAudioSource = "";
+let currentAudioVolume = 0;
+
+window.addEventListener("load", function () {
+  backgroundController.setImage();
+  spineController.create();
+  audioController.play();
+});
+
+window.addEventListener("resize", () => {
+  spineController.adjustCanvas();
+});
+
+window.wallpaperRegisterListener = {
+  applyGeneralProperties: function (properties) {
+    if (properties.fps) {
+      // wallpaperSettings.fps = properties.fps;
+    }
+  },
+  applyUserProperties: function (properties) {
+    if (properties.preset) {
+      const preset = properties.preset.value;
+      let { backgroundImage, spineConfig, audioOptions } =
+        presetController.set(preset);
+      backgroundController.changeImage(backgroundImage);
+      spineController.changeConfig(spineConfig);
+      audioController.changeOptions(audioOptions);
+    }
+    if (properties.audio_file) {
+      const audio_file = properties.audio_file.value;
+      currentAudioSource = audio_file;
+      audioController.changeSource(audio_file);
+    }
+    if (properties.audio_volume) {
+      const audio_volume = properties.audio_volume.value;
+      currentAudioVolume = audio_volume;
+      audioController.changeVolume(audio_volume);
+    }
+  },
+};
+
+window.wallpaperPropertyListener = {
+  applyGeneralProperties: function (properties) {
+    if (properties.fps) {
+      // wallpaperSettings.fps = properties.fps;
+    }
+  },
+  applyUserProperties: function (properties) {
+    if (properties.preset) {
+      const preset = properties.preset.value;
+      let { backgroundImage, spineConfig, audioOptions } = presetController.set(
+        preset,
+        currentAudioSource,
+        currentAudioVolume
+      );
+      backgroundController.changeImage(backgroundImage);
+      spineController.changeConfig(spineConfig);
+      audioController.changeOptions(audioOptions);
+    }
+    if (properties.audio_file) {
+      const audio_file = properties.audio_file.value;
+      currentAudioSource = audio_file;
+      audioController.changeSource(audio_file);
+    }
+    if (properties.audio_volume) {
+      const audio_volume = properties.audio_volume.value;
+      currentAudioVolume = audio_volume;
+      audioController.changeVolume(audio_volume);
+    }
+  },
+};
diff --git a/dist/scripts/preset-store.js b/dist/scripts/preset-store.js
deleted file mode 100644
index f5ee421..0000000
--- a/dist/scripts/preset-store.js
+++ /dev/null
@@ -1,40 +0,0 @@
-const PresetStore = {
-  kv37: {
-    backgroundImage: "./assets/images/kv37_xilian.png",
-    spineConfig: {
-      jsonUrl: "./assets/effects/kv37.json",
-      atlasUrl: "./assets/images/kv37.atlas",
-      animation: "animation",
-      viewport: {
-        x: -1215,
-        y: -410,
-        width: 2048,
-        height: 1024,
-      },
-    },
-    audioOptions: {
-      source: "./assets/audios/pv37.mp3",
-      volume: 0.5,
-    },
-  },
-  xilian: {
-    backgroundImage: "./assets/images/ava.jpg",
-    spineConfig: {
-      jsonUrl: "./assets/effects/xilian.json",
-      atlasUrl: "./assets/images/xilian.atlas",
-      animation: "idle",
-      viewport: {
-        padLeft: "-25%",
-        padRight: "-28%",
-        padTop: "-30%",
-        padBottom: "-23%",
-      },
-    },
-    audioOptions: {
-      source: "./assets/audios/「再度和你」.flac",
-      volume: 0.5,
-    },
-  },
-};
-
-export default PresetStore;
diff --git a/dist/scripts/presets.js b/dist/scripts/presets.js
new file mode 100644
index 0000000..39d8b1a
--- /dev/null
+++ b/dist/scripts/presets.js
@@ -0,0 +1,12 @@
+// 预设索引：把每份壁纸自己的 preset.js 汇总成 id → 预设 的查表。
+//
+// id 必须与 project.json 里 combo 选项的 value 一致（xilian / kv37），
+// 改了会让老用户已保存的预设选择失效，所以 id 永远跟着 WE 属性走，
+// 而目录名（游戏名/壁纸显示名）是给人看的、可以改。
+
+import xilian from "../assets/崩坏：星穹铁道/昔涟立绘/preset.js";
+import kv37 from "../assets/崩坏：星穹铁道/「成为昨日的明天」/preset.js";
+
+const Presets = Object.fromEntries([xilian, kv37].map((preset) => [preset.id, preset]));
+
+export default Presets;
diff --git a/docs/adr/0001-resource-layout.md b/docs/adr/0001-resource-layout.md
new file mode 100644
index 0000000..17a2aa2
--- /dev/null
+++ b/docs/adr/0001-resource-layout.md
@@ -0,0 +1,7 @@
+# 资源按 游戏/壁纸 分层，显示名做目录、id 做键
+
+已发布作品（workshopid 3604974793）原先把两套壁纸的资源混在 `assets/{images,effects,audios}/` 三个平铺目录里，加第三档就必须靠文件名前缀认领。我们改为每档壁纸自包含：`assets/<游戏>/<壁纸>/{effects,images,audios}/`，并让每档壁纸自带一份 `preset.js`。
+
+关键取舍是**目录名用显示名（含 `「」` 等符号），而代码里的键用 ASCII 的预设 id**。反过来做（目录名用 id）会让目录结构在 WE 的文件夹里毫无可读性；统一用显示名做键则会在改标题时打断老用户已保存的预设选择。所以两者各司其职：显示名服务于人，id 服务于 WE 属性与用户设置，二者用 `preset.js` 里的 `id` 字段绑定。
+
+保留了 `effects/`、`images/`、`audios/` 这三层同名子目录，是为了让 Spine 骨架 JSON 里的 `"images": "../images/"` 相对路径一字不改。
diff --git a/docs/adr/0002-preset-as-es-module.md b/docs/adr/0002-preset-as-es-module.md
new file mode 100644
index 0000000..c48c322
--- /dev/null
+++ b/docs/adr/0002-preset-as-es-module.md
@@ -0,0 +1,7 @@
+# 预设用 ES module 而不是 JSON
+
+每档壁纸的 `preset.js` 是 `export default {...}` 的 ES module，而不是由 `fetch` 拉取的 `preset.json`。
+
+理由是资源路径的自包含性：模块内用 `import.meta.url` 推导 `./images/...` 的绝对 URL，于是整个壁纸目录可以被复制、改名、搬家而不需要改任何一行路径。若用 JSON，路径只能以**页面**为基准写死，一旦目录改名（本项目的目录名就是显示名，改标题=改目录）就会全站 404，且每档壁纸都必须先异步取回 JSON 才能建播放器，给启动时序又加一个竞态点。
+
+代价：配置文件不再是纯数据，不能直接 `JSON.parse` 消费。本项目接受这一点——预设数据量极小，且始终由代码持有。
diff --git a/tools/check-paths.mjs b/tools/check-paths.mjs
new file mode 100644
index 0000000..4624f20
--- /dev/null
+++ b/tools/check-paths.mjs
@@ -0,0 +1,49 @@
+// 静态检查：每份 preset.js 里声明的每一个资源路径是否真实存在。
+// 这能抓到"运行时才会暴露"的拼写错误（比如某首备用 BGM 从未被加载过，写错了也不会有人发现）。
+// 用法：node tools/check-paths.mjs
+
+import { stat } from "node:fs/promises";
+import { fileURLToPath, pathToFileURL } from "node:url";
+import { glob } from "node:fs/promises";
+import { resolve } from "node:path";
+
+const root = resolve("dist");
+const presetFiles = [];
+for await (const f of glob("assets/**/preset.js", { cwd: root })) presetFiles.push(f);
+
+let ok = 0;
+let bad = 0;
+
+for (const rel of presetFiles.sort()) {
+  const mod = await import(pathToFileURL(resolve(root, rel)).href);
+  const preset = mod.default;
+  const urls = [];
+  const walk = (value, path) => {
+    if (typeof value === "string" && /^(file|https?):/.test(value)) urls.push([path, value]);
+    else if (value && typeof value === "object") {
+      for (const [k, v] of Object.entries(value)) walk(v, `${path}.${k}`);
+    } else if (Array.isArray(value)) value.forEach((v, i) => walk(v, `${path}[${i}]`));
+  };
+  walk(preset, preset.id);
+
+  console.log(`\n${rel}  (id=${preset.id}, name=${preset.name})`);
+  for (const [path, url] of urls) {
+    const u = new URL(url);
+    if (u.protocol !== "file:") {
+      console.log(`  ?  ${path} -> 非本地路径，跳过: ${url}`);
+      continue;
+    }
+    const file = fileURLToPath(u);
+    const info = await stat(file).catch(() => null);
+    if (info?.isFile()) {
+      console.log(`  ok ${path}  (${(info.size / 1024).toFixed(1)} KB)`);
+      ok++;
+    } else {
+      console.log(`  MISSING ${path} -> ${file}`);
+      bad++;
+    }
+  }
+}
+
+console.log(`\n${ok} 个路径存在，${bad} 个缺失`);
+process.exit(bad ? 1 : 0);
diff --git a/tools/compare.mjs b/tools/compare.mjs
new file mode 100644
index 0000000..aecf092
--- /dev/null
+++ b/tools/compare.mjs
@@ -0,0 +1,58 @@
+// 对拍比较：把两批截图逐对做差值，给出"改完到底有没有动到画面"的判定。
+// 用法：node tools/compare.mjs <A目录> <B目录> [--tag A] [--tag B] [--threshold 1.0]
+// 例：  node tools/compare.mjs before after
+
+import { spawn } from "node:child_process";
+import { readdir } from "node:fs/promises";
+import { resolve } from "node:path";
+
+const argv = process.argv.slice(2);
+const [dirA, dirB] = argv;
+if (!dirA || !dirB) {
+  console.error("usage: node tools/compare.mjs <dirA> <dirB> [--threshold 1.0]");
+  process.exit(2);
+}
+const opt = (name, dflt) => {
+  const i = argv.indexOf(`--${name}`);
+  return i >= 0 ? argv[i + 1] : dflt;
+};
+const threshold = Number(opt("threshold", "1.0"));
+
+function run(cmd, args) {
+  return new Promise((resolve) => {
+    const p = spawn(cmd, args, { stdio: ["ignore", "pipe", "pipe"] });
+    let out = "";
+    p.stdout.on("data", (d) => (out += d));
+    p.stderr.on("data", (d) => (out += d));
+    p.on("close", () => resolve(out));
+  });
+}
+
+const A = resolve("tools/shots", dirA);
+const B = resolve("tools/shots", dirB);
+const files = (await readdir(A)).filter((f) => f.endsWith(".png") && !f.endsWith(".ref.png")).sort();
+
+let worst = 0;
+let worstName = "";
+let failed = 0;
+
+for (const f of files) {
+  const a = resolve(A, f);
+  const b = resolve(B, f);
+  const out = await run(process.execPath, ["tools/diff.mjs", a, b]);
+  const m = out.match(/mean\|diff\|=([\d.]+)/);
+  const mean = m ? Number(m[1]) : NaN;
+  const verdict = Number.isNaN(mean) ? "MISSING" : mean < threshold ? "same" : "CHANGED";
+  if (Number.isNaN(mean)) failed++;
+  else if (mean > worst) {
+    worst = mean;
+    worstName = f;
+  }
+  console.log(`${f.padEnd(28)} mean|diff|=${String(mean).padStart(7)}   ${verdict}`);
+}
+
+console.log(`\n${dirA} → ${dirB}：${files.length} 对；最大差异 ${worst.toFixed(3)}/255（${worstName || "无"}）；判定阈值 ${threshold}`);
+if (failed) {
+  console.log(`${failed} 对缺少对照文件`);
+  process.exit(1);
+}
diff --git a/tools/heatmap.mjs b/tools/heatmap.mjs
new file mode 100644
index 0000000..3e27ded
--- /dev/null
+++ b/tools/heatmap.mjs
@@ -0,0 +1,47 @@
+// 把两张图的差异降采样成 ASCII 热力图，好在纯文本里看出"差异落在画面哪里"。
+// 用法：node tools/heatmap.mjs <a.png> <b.png> [cols] [rows]
+
+import { spawn } from "node:child_process";
+
+const [a, b, cols = "48", rows = "20"] = process.argv.slice(2);
+if (!a || !b) {
+  console.error("usage: node tools/heatmap.mjs <a.png> <b.png> [cols] [rows]");
+  process.exit(2);
+}
+
+const W = Number(cols);
+const H = Number(rows);
+const RAMP = " .:-=+*#%@";
+
+const buf = await new Promise((resolve) => {
+  const p = spawn(
+    "ffmpeg",
+    [
+      "-hide_banner", "-loglevel", "error",
+      "-i", a, "-i", b,
+      "-lavfi", `blend=all_mode=difference,format=gray,scale=${W}:${H}:flags=area`,
+      "-f", "rawvideo", "-pix_fmt", "gray", "-",
+    ],
+    { stdio: ["ignore", "pipe", "pipe"] },
+  );
+  const chunks = [];
+  p.stdout.on("data", (d) => chunks.push(d));
+  p.on("close", () => resolve(Buffer.concat(chunks)));
+});
+
+if (buf.length < W * H) {
+  console.error(`ffmpeg 只返回 ${buf.length} 字节，期望 ${W * H}`);
+  process.exit(1);
+}
+
+console.log(`${a}  vs  ${b}   (${W}x${H} 降采样，越亮=差异越大)`);
+console.log("    +" + "-".repeat(W) + "+");
+for (let y = 0; y < H; y++) {
+  let line = "";
+  for (let x = 0; x < W; x++) {
+    const v = buf[y * W + x];
+    line += RAMP[Math.min(RAMP.length - 1, Math.round((v / 255) * (RAMP.length - 1) * 2))];
+  }
+  console.log(String(y).padStart(3) + " |" + line + "|");
+}
+console.log("    +" + "-".repeat(W) + "+");
diff --git a/tools/serve.mjs b/tools/serve.mjs
index 24ead24..6033851 100644
--- a/tools/serve.mjs
+++ b/tools/serve.mjs
@@ -84,6 +84,16 @@ const DRIVER = (q) => `<script>
     var origDraw = proto.drawFrame;
     proto.drawFrame = function () {
       state.drawCalls = (state.drawCalls || 0) + 1;
+      // 冻结只做一次是不够的：相位可能在成功回调前后被推进过一帧。这里每帧都强制归零，
+      // 保证"同一份代码的任何两次截图"是同一相位，对拍才有意义。
+      if (freeze) {
+        try {
+          var cur = this.animationState && this.animationState.getCurrent(0);
+          if (cur) cur.trackTime = 0;
+          if (this.skeleton) this.skeleton.updateWorldTransform(2);
+          this.viewportTransitionStart = performance.now() - 1e6;
+        } catch (e) { state.error = "freeze-frame: " + e; }
+      }
       return origDraw.apply(this, arguments);
     };
   }
@@ -94,6 +104,9 @@ const DRIVER = (q) => `<script>
       var cur = p.animationState && p.animationState.getCurrent(0);
       if (cur) cur.trackTime = 0;
       if (p.skeleton) p.skeleton.updateWorldTransform(2);
+      // 视口过渡（transitionTime 默认 0.25s）是时间相关的插值，会把"冻结"变得不彻底：
+      // 把它推到足够久以前，transitionAlpha >= 1，直接使用 currentViewport。
+      p.viewportTransitionStart = performance.now() - 1e6;
       state.info = {
         animations: p.skeleton ? p.skeleton.data.animations.map(function (a) { return a.name; }) : [],
         skin: p.skeleton ? p.skeleton.data.skins.map(function (s) { return s.name; }) : [],