style: scrollbar optimize

[SailFlorve]

Pull Request Template

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Summary

The original scroll bar color was hardly visible, so I chose a progress bar color that suits both light and dark themes. Also, the original .scrollbar-transparent was not transparent. Now it has been fixed, so the scrollbar disappears when the mouse moves away from the nav list.

Change Type

Please delete any irrelevant options.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Documentation update
• Translation update

Testing

Test Configuration:

Checklist

• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• I have commented in any complex areas of my code
• I have made pertinent documentation changes
• My changes do not introduce new warnings
• I have written tests demonstrating that my changes are effective or that my feature works
• Local unit tests pass with my changes
• Any changes dependent on mine have been merged and published in downstream modules.

[danny-avila]

Resolved by #2138