New landing page, prefers-color-scheme, prefers-reduced-motion

[0xdade]

This will close #340.

I think it's ready for consideration.

• New landing page that also has support for login/reg if required.
• prefers-color-scheme is now honored and a dark theme is offered when requested
• prefers-reduced-motion is now honored and animation is reduced to a minimum when set
• Restructure a bunch of css into subpages
• Update stylelint rules to work with scss
• Update codeclimate to use stylelint
• stylelint in pre-commit hooks

[codeclimate]

Code Climate has analyzed commit 5ad528f and detected 1 issue on this pull request.

Here's the issue category breakdown:

Category	Count
Complexity	1

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[ajacques]

First Pass

[0xdade]

Accidentally upset codeclimate again because stylelint has some issues with @mixin and @include despite claiming it has support for scss. But now that I've done all this again, I think it actually makes the most sense to do color-theme switches with native css variables instead of scss variables. This codepen has a pretty good example, showing that we can set variables based on a selector matching or not. This should reasonably be able to extend to media queries, too, and also allows us to make other themes more easily in the future if we want.

[ajacques]

What do you think about these names that are a bit more intuitive?

doesUserPreferReducedMotion()
isDarkMode
isLightMode

[0xdade]

I originally used a isDarkMode and isLightMode but that, to me, implies a boolean response, which right now is inaccurate. I could return .matches which then gives us a boolean, but makes it so you can't register event handlers on it if you so choose.

[matteobruni]

I suggest tsParticles https://github.com/matteobruni/tsparticles instead of this obsolete library. You'll have less CPU usage client-side and tsParticles it's written in TypeScript. You can have also more configurations