The line-highlighting doesn't line up with the line

[Charlie Rubruck]

As you can see in the screenshot, neither the blue keyword highlight, nor the teal line marker, actually lines up with the appropriate line:

This gets worse additively with each line further down.

Tested with Chrome, and Edge.

[Jens Hofschröer]

Seems to be a regression with webkit browsers. In FF all is correct.

[Charlie Rubruck]

I'll try FF then, thanks. Any good idea for a fix though? Not a webdev here. XD

Edit: It does work just fine in FF. Just Chromium seems to have issues.