Include custom css with variables but not inline

I want to show a progressbar and found a simple solution where the progress is displayed with a css value.

Can I somehow pass values from the content files markdown metadata to a css that is included as a file?

My current solution uses partials to make inline styles but these styles are forbidden on the server.

I doubt that I can use some of these workarounds:

So think of this in

title: progress
current: 50
goal: 100

I would calculate the procent value (eg 50%) and insert this into my custom style.
As partial with inline style this works fine.

Can I somehow write the computed styles to a file (via the resources mechanism) and include them as a css file?


I solved it after writing this post with: