[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.

Comienza en la página del tutorial de Tic-Tac-Toe y reproduce el problema descargando varios ejemplos de CodeSandbox. Inspecciona cada src/styles.css extraído y compáralo con el código fuente del tutorial; después, rastrea cómo se generan los archivos de la sandbox. Se considera terminado cuando cada hoja de estilos generada contiene solo una copia de las reglas de * y body.