[Bug]: Tic-Tac-Toe sandbox download contains duplicate CSS rules

Summary

The CodeSandbox generated from the Tic-Tac-Toe tutorial contains duplicate * and body CSS rules in src/styles.css.
The declarations are identical and do not affect the rendered result, but the duplication may confuse beginners following the tutorial.

Page

https://react.dev/learn/tutorial-tic-tac-toe

Details

Steps to reproduce:

1. Open the Tic-Tac-Toe tutorial.
2. Fork one of the interactive examples in CodeSandbox.
3. Download and extract the sandbox.
4. Open src/styles.css.

The * and body rules appear twice with identical declarations.
I confirmed the same duplication in multiple examples on the tutorial page.
The tutorial source defines them only once per example, so the duplication appears to occur when the sandbox files are generated.

Expected result:

src/styles.css contains only one copy of each rule.

从 Tic-Tac-Toe 教程页面开始，通过下载多个 CodeSandbox 示例来复现该问题。检查每个提取出的 src/styles.css，并将其与教程源代码进行比较，然后追踪 sandbox 文件的生成方式。完成标准是每个生成的样式表只包含一份 * 和 body 规则。