Hello

Thank you for your query.

These CSS files are minified in order to reduce the file size and facilitate faster loading of the site. Also it is not recommended to alter these files. Instead you should use custom CSS section or custom CSS file to overwrite rules.

Here is the documentation for custom css, for your kind convenience:

https://www.joomshaper.com/documentation/helix-framework/helix-ultimate-2/custom-code-css-js-meta