[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.

從 Tic-Tac-Toe 教學頁面開始，透過下載多個 CodeSandbox 範例來重現問題。檢查每個擷取出的 src/styles.css，並將其與教學原始碼進行比較，然後追蹤 sandbox 檔案的產生方式。完成標準是每個產生的樣式表只包含一份 * 和 body 規則。