sass: follow bg selector: fix typo
sass: fix follow bg selector
sass: dim background on popups, unify impl
mobile: follow: bring back click-outside-to-close
sass: social share: do not hide text on narrow

it does fit
sass: page__related: remove a override
archive-single: remove one layer of unneeded div
remove rel="permalink"

weird custom rel usage without any obvious effect
git: ignore vendor assets
print: don't draw light/dark toggle
fa: self-host
profile: remove platform-specific link generators

those are dumb when you have a generic one
links: simplify sa usage
fa: fav4-ify
page__meta: fa: always fixed width

ruby: depends on matrix, for classifier-reborn, for ruby 3.1
un-vendor lunr, use npm to copy
js: cleanup, un-webpackify, trim unused
font: use system, dim colors

let's respect users' choice, and emulate the original light touch by
color. this removes the major source of current loaded assets size.
those don't have proper cjk font probably cannot read chinese anyway.
about: fix my english