Empty highlighted lines

[artola]

I do // [!code highlight:100] to highlight a region, such lines content line-breaks, and when styling them, they collapse as has no content (0 height).
Is it better to use CSS to force the height to 1lh? or use some plugin to insert into the empty nodes a char. For example "\200B", for "Zero-width space".
I find them not optimal and I will appreciate any suggestion.