Horizontal scrollbar in fenced code blocks not visible on the dark theme

[dkasak]

It's there since I'm able to click on it and scroll, but I suppose it's the same colour as the background.

[turt2live]

Duplicate of #4256

[dkasak]

Is this really a duplicate? I found that issue but it seemed different: the screenshots there do show the scrollbar, it's just partially hidden by the text. Also, I seem to remember that prior to the redesign the scrollbars on <pre> blocks were visible for me.

[turt2live]

It's a further regression, but the issue appears to be the same afaict