[openstreetmap/openstreetmap-website] Dark Mode (#2332)

[Vitaly Zdanevich]

I can implement `prefers-color-scheme` for website, MVP: for `header` only. Please approve me and I will do it, for this first pull request it must be only a few lines of CSS.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/openstreetmap/openstreetmap-website/issues/2332#issuecomment-554696072
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/rails-dev/attachments/20191116/f487645a/attachment.html>