Simple Dark Theme Bookmarklet for web pages

darkthemeswitcher-inline.js

javascript:(d=>{var css=`:root{background-color:#fefefe;filter:invert(100%)}*{background-color:inherit}img:not([src*=".svg"]),video{filter: invert(100%)}`,style,id="dark-theme-snippet",ee=d.getElementById(id);if(null!=ee)ee.parentNode.removeChild(ee);else {style = d.createElement('style');style.type="text/css";style.id=id;if(style.styleSheet)style.styleSheet.cssText=css;else style.appendChild(d.createTextNode(css));(d.head||d.querySelector('head')).appendChild(style)}})(document)

darkthemeswitcher.js

javascript:
(d=>{
  var css = `
        :root{
          background-color: #fefefe;
          filter: invert(100%)
        }
        * {
          background-color: inherit
        }
        img:not([src*=".svg"]), video{
          filter: invert(100%)
        }
  `,
  style,
  id="dark-theme-snippet",
  ee = d.getElementById(id);
  if (null != ee) ee.parentNode.removeChild(ee);
  else {
    style = d.createElement('style');
    style.type = "text/css";
    style.id = id;
    if (style.styleSheet) style.styleSheet.cssText = css;
    else style.appendChild(d.createTextNode(css));
    (d.head||d.querySelector('head')).appendChild(style);
  }
})(document)

this one is also good: https://sanketmehta7.github.io/DarkMode-JS-BookMark/ and this: https://lnikki.la/articles/night-mode-css-filter/

Cool! The first one indeed doesn't ruin images...but instead hides some text (unlike the code here).
The second one looks almost identical to the code here, i.e. ruins images. The ruined images look a bit more natural than the code here, but still. Yet worse still, it's also irreversible, unlike the code here that can be switched back and forth.

I've forked it into a version that does not ruin iframes (like embedded YouTube) and images that use background-image= instead of <img.