Sorry, I was not being clear on the problem. It’s a ghetto method that I’ve done where I used the skin extension to make the wiki page dark using CSS. By default, xwiki uses background color that is white, so the latex rendering is not an issue as it is dark text over light background but thats not the case in my situation where its dark text over dark background.
And moreover, yes the use case is not the generated PDF. I’ll try to edit preamble and see if xcolor package works, however, I assume that would affect the pdf export as well?
Regarding with the docker, I’ve installed the default image, blang/latex:ubuntu, using docker engine but its recognised?