Dark mode support for code reloader error pages

[jonnytest1]

could use some thoughts on which colors to pick but hey its dark ^^

[ryanwinchester]

The text needs some more contrast but this would be very helpful while streaming programming so as to not flashbang viewers

[03juan]

I think @style.accent also should be tweaked.

[03juan]

Alternatively, also provide configurable assigns for background colors, and let users override it by implementing their own debug handler and passing custom fg, bg, accent, etc. colors

[jonnytest1]

yeah should definitely be configurable since the other colors are , it would be very counterintuitive if the defined color isnt the one displayed

alternative

filter: invert(1);

can also be considered (another invert(1) for the logo to be orange again )

[rhcarvalho]

Hi @jonnytest1 💜

Considering the code changes, I'd suggest updating the title of the PR to help the Phoenix team more quickly understand the scope when triaging the open PRs. E.g.: "Dark mode support for code reloader error pages".