I'll be more than happy to contribute once everything becomes more clear.
For now I'm experimenting with some input from THEMES.md. It's still unspecified what I initially wanted to get rid of: the bright (white) glow around the carousel bar.
I have changed my carousel bar into a darker colour and a bright glow seems a bit out of place for my new theme...
I'm looking at other themes that don't feature this but it doesn't seem to be within the
carousel element (or anywhere else for that matter).