Disable the sticky top bar on Stack Exchange sites

se_no_sticky_topbar.user.js

// ==UserScript==
// @name        SE No Sticky Top Bar
// @namespace   https://github.com/vyznev/
// @description Disables the sticky top bar on Stack Exchange sites
// @author      Ilmari Karonen
// @version     0.3.0
// @copyright   2021-2022, Ilmari Karonen
// @downloadURL https://gist.github.com/vyznev/7c9a7ddc5c057d4c895864e460b4a88d/raw/se_no_sticky_topbar.user.js
// @homepageURL https://meta.stackexchange.com/a/368984
// @match       *://*.stackexchange.com/*
// @match       *://*.stackoverflow.com/*
// @match       *://*.superuser.com/*
// @match       *://*.serverfault.com/*
// @match       *://*.stackapps.com/*
// @match       *://*.mathoverflow.net/*
// @match       *://*.askubuntu.com/*
// @exclude     *://chat.*/*
// @exclude     *://blog.*/*
// @grant       none
// @run-at      document-start
// @noframes
// ==/UserScript==

var css = `
  html:not(.specificity-hack) { --top-bar-allocated-space: 0px; }
  body:not(.specificity-hack) { padding-top: 0px; }
  .s-topbar.ps-fixed:not(.specificity-hack) { position: static !important; }
`;

var style = document.createElement('style');
style.textContent = css;

var parent = (document.head || document.documentElement);
if (parent) parent.appendChild(style);
else {
  // work-around for https://github.com/greasemonkey/greasemonkey/issues/2996
  var obs = new MutationObserver(function () {
    var parent = (document.head || document.documentElement);
    if (parent) { obs.disconnect(); parent.appendChild(style); }
  });
  obs.observe(document, {childList: true});
}