[Feature]Mode Night and Keep the selected CSS

[PaulYoung-hub]

Hello 😊, could you please add a night mode to the extension? The current mode is a bit harsh on the eyes 👀.

Please ensure that the selected CSS is maintained. You can refer to the video for a clearer explanation.

Thank You 😀

https://github.com/user-attachments/assets/806f0499-ef22-4611-b328-fc3cad9ad5cd