No one bothers, everyone moves all of their JS to an external file (which is what i'm working on now) or they just don't bother with CSP headers at all.
>It will be difficult to deal with some styling functions from Arc, like `grayrange` that's greying out comments with negative score. Perhaps JS is more suitable?
The score for each comment could be added as a data attribute and JS could apply the style based on that. Offloading that to JS might make the forum more responsive.
...as well as, maybe, having markdown done entirely in JS, but that's for the future.
 ... as well as maybe thread folding with JS and localstorage.