Add support for light mode

[troccoli]

This PR adds a theme switcher and supports for light mode. The default is still dark mode though. It has been done with the help of Codex AI.

• CSS variables have been added for both dark and light mode and used throughout.

• The logos in the Community section on the homepage have been left unaltered, as I would have had to research each company to understand how to correctly display their logo in light mode.

• By default the syntax highlight themes are dracula for dark mode and github-light for light mode. They can be customised by the TORCHLIGHT_DARK_THEME and TORCHLIGHT_LIGHT_THEME env variables.

For reference I have attached the plan I and Codex followed and the audit file used during the plan.

LIGHT_MODE_PLAN.md
LIGHT_MODE_AUDIT.md

Questions for the reviewer(s)

1. I have converted the homepage too, but I can revert that back if you prefer. I am interested mainly in the documentation part of the site.
2. I have used CSS variables as I said above, instead of the
   dark: class modifier. If you prefer using the Tailwind classes directly I can have a go at converting something like bg-[var(--theme-bg)] to bg-white dark:bg-zinc-900
3. I have taken the liberty to add my name to the footer. Let me know if that's ok

[troccoli]

Is anybody available for a review?

[nunomaduro]

@nunowar

[nunowar]

It needs some improvements. I'll make them and merge soon. Thanks!

[troccoli]

Of course. I used Codex so that's natural. I look forward to see your changes. And thanks again

[nunomaduro]

@nunowar why do we need light mode tho?

[nunowar]

@nunowar why do we need light mode tho?

That's a good question. Personally, I don't miss this feature, but some people prefer reading in light mode, especially on documentation pages. We can add it soon, but I want to do it properly and keep the PEST brand strong and consistent across both modes...

[troccoli]

Because there are a lot of people, like me, who find it very hard to read in dark mode. I personally cannot look at a dark mode site for more than 30 seconds before my eyes get blurry.

[troccoli]

It's about usability. The same reason we have keyboard shortcuts, add alt text, and use aria attributed.