The CSS for our default themes are built with webpack and can't be modified after the fact.
There's content integrity hashes that we actually can't remove and are forced by a dependency, so any change to them will cause that hash to be broken.
Even if we could remove that, any direct changes would be lost the moment you updated.
You can create a custom default_layout template (in a html_custom folder as
described here at item #1) and then replace the default CSS inclusion with your own
The line that includes our default CSS:
Code:
{{ encore_entry_link_tags('huraga') }}
You could also split huraga off into your own theme, or if these are changes which would be widely applicable you can modify the source code directly and submit a pull request to get them shipped within FOSSBilling.
The relevant source files are here:
https://github.com/FOSSBilling/FOSSBilli...aga/assets.
There's also paid themes which from my understand work by being injected into the existing theme, though I can't personally comment on the quality of this, I just know it exists.
https://www.zomex.com/products/fossbilling-templates/