diff --git a/README.md b/README.md
index 83af9cc..081f929 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@
 ├─ pyproject.toml          # uv 环境与导出依赖
 ├─ uv.lock                 # 依赖锁定
 ├─ scripts/export_pdf.py   # PDF 导出脚本
+├─ 封面demo.pdf            # 导出的 PDF 样例
 ├─ assets/
 │  ├─ css/style.css        # 布局、字号与各元素配色
 │  ├─ js/scene.js          # 场景数据与网格渲染
@@ -40,8 +41,8 @@ python -m http.server 8000
 
 ```bash
 uv sync
-uv run python scripts/export_pdf.py              # 默认 1em = 24px，输出 dist/luori.pdf
-uv run python scripts/export_pdf.py --em 16 -o dist/luori-16.pdf
+uv run python scripts/export_pdf.py              # 默认 1em = 24px，输出 封面demo.pdf
+uv run python scripts/export_pdf.py --em 16 -o 封面demo-16.pdf
 ```
 
 脚本优先调用本机 Edge / Chrome；若都未安装，可先下载 Playwright Chromium：
diff --git a/assets/js/scene.js b/assets/js/scene.js
index 386959a..aef877b 100644
--- a/assets/js/scene.js
+++ b/assets/js/scene.js
@@ -39,11 +39,10 @@
 
   /* 飞鸟：数量减少，间距不等，仅少量成对；上下拉开分布 */
   const birds = [
-    { x: 0, y: 2, kind: 'magpie' },
-    { x: 26, y: 2, kind: 'magpie' },
+    { x: 25, y: 2, kind: 'magpie' },
     { x: 1, y: 4, kind: 'sparrow' },
     { x: 3, y: 8, kind: 'crow' },
-    { x: 6, y: 13, kind: 'magpie' },
+    { x: 9, y: 13, kind: 'magpie' },
     { x: 9, y: 15, kind: 'sparrow' },
     { x: 26, y: 5, kind: 'crow' },
     { x: 17, y: 9, kind: 'sparrow' },
diff --git a/scripts/export_pdf.py b/scripts/export_pdf.py
index e23d2db..4e69fbb 100644
--- a/scripts/export_pdf.py
+++ b/scripts/export_pdf.py
@@ -5,7 +5,7 @@
 
 用法：
     uv run python scripts/export_pdf.py
-    uv run python scripts/export_pdf.py --em 16 -o dist/luori-16.pdf
+    uv run python scripts/export_pdf.py --em 16 -o 封面demo-16.pdf
 """
 
 from __future__ import annotations
@@ -138,8 +138,8 @@ def main() -> None:
         "-o",
         "--out",
         type=pathlib.Path,
-        default=ROOT / "dist" / "luori.pdf",
-        help="输出文件路径，默认 dist/luori.pdf",
+        default=ROOT / "封面demo.pdf",
+        help="输出文件路径，默认 封面demo.pdf",
     )
     args = parser.parse_args()
     if args.em <= 0:
diff --git a/封面demo.pdf b/封面demo.pdf
new file mode 100644
index 0000000..1030ce1
Binary files /dev/null and b/封面demo.pdf differ