Colorscheme refactoring and fixes

[gdjohn4s]

Description

As stated in the title, this PR aims to improve the code regarding the color scheme.

Proposed Changes

In detail:

• Color detection
• Use of classes instead of data-theme
• Removed "dark" state, now only "default" and "light" exist
• Code cleanup
• Removed unused code

The reason for these changes is code optimization.

Checklist

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• [x] Pull request description clearly describes the changes included in the pull request.
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• [x] Each table column is padded with one space on either side
• [x] I have searched the repository for any relevant issues or pull requests
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