几个常用网站的 dark theme，基于 stylish，看不惯亮色的可以试试~

[MajestySolor]

Google https://userstyles.org/styles/102870/gt-deepdark-for-google-legacy
Youtube https://userstyles.org/styles/102050/dark-youtube-nights
Twitch https://userstyles.org/styles/78830/twitch-tv-dark-black-customisable-theme
Github https://github.com/StylishThemes/GitHub-Dark

另外一个封装成插件形式的样式包，美化 Gmail Gcal Gdocs
https://www.globexdesigns.com/products/gr/install.php

firefox的黑色皮肤，黑到没朋友
https://addons.mozilla.org/en-US/firefox/addon/ft-deepdark/