Poor man’s night mode

nm-bookmarklet.txt

javascript:(function()%7Bvar%20nightEnabled%20%3D%20document.head.querySelector(%22%23my-night-style%22)%3Bif%20(nightEnabled)%20%7Bdocument.head.removeChild(nightEnabled)%3B%7D%20else%20%7Bvar%20nightStyle%20%3D%20document.createElement(%22style%22)%3BnightStyle.id%20%3D%20%22my-night-style%22%3BnightStyle.textContent%20%3D%20%22html%20%7Bfilter%3A%20invert(100%25)%20hue-rotate(180deg)%3B%7D%20img%2C%20svg%20%7Bfilter%3A%20invert(100%25)%20hue-rotate(180deg)%20!important%3B%7D%20video%20%7Bfilter%3A%20invert(100%25)%20hue-rotate(180deg)%20!important%3B%7D%22%3Bdocument.head.appendChild(nightStyle)%3B%7D%7D)()

Converted using Mr Coles’ Bookmarklet Creator: https://mrcoles.com/bookmarklet/

nm.css

/* Alternatively, as a stylesheet you can automatically load in the browser (e.g. advanced prefs in Safari) */

html {
  filter: invert(100%) hue-rotate(180deg);
} 
img, svg {
  filter: invert(100%) hue-rotate(180deg) !important;
} 
video {
  filter: invert(100%) hue-rotate(180deg) !important;
}

nm.js

var nightEnabled = document.head.querySelector("#my-night-style");
if (nightEnabled) {
  document.head.removeChild(nightEnabled);
} else {
  var nightStyle = document.createElement("style");
  nightStyle.id = "my-night-style";
  nightStyle.textContent = "html {filter: invert(100%) hue-rotate(180deg);} img, svg {filter: invert(100%) hue-rotate(180deg) !important;} video {filter: invert(100%) hue-rotate(180deg) !important;}";
  document.head.appendChild(nightStyle);
}