Add background on hover to bullet points in preview mode

When you hover over a foldable bullet point in source mode, a circular grey background appears. E.g. I hovered over the first bullet here:

Bildschirmfoto 2023-11-05 um 03.06.32

This background shadow doesn’t appear in preview mode:

Bildschirmfoto 2023-11-05 um 03.06.39

I would like to add the shadow through css also in preview mode.

Things I have tried

I inspected with developer tools and tried to have a look what the underlying css is in source mode. I think it should be somewhere under HyperMD-list-line HyperMD-list-line-1 cm-line, but I didn’t find it. I only found --list-marker-color-hover, but that doesn’t change the color in preview mode.

Thanks in advance!