GitHub apply dark theme on private repo

github-apply-dark-theme-on-private-repos.user.js

// ==UserScript==
// @name         GitHub apply dark theme on private repo
// @namespace    https://github.com/benok/
// @description  Apply dark theme to your private repository pages on Github
// @match        https://github.com/*
// @run-at       document-idle
// @version      2022.11.30.0
// @homepage     https://gist.github.com/benok/301f7a9667a598202f10111af054ae77
// @downloadURL  https://gist.github.com/benok/301f7a9667a598202f10111af054ae77/raw/github-apply-dark-theme-on-private-repos.user.js
// @updateURL    https://gist.github.com/benok/301f7a9667a598202f10111af054ae77/raw/github-apply-dark-theme-on-private-repos.user.js
// @author       benok
// @grant        none
// @license      MIT
// ==/UserScript==

(function() {
    'use strict';

    if (document.querySelector('span.Label.Label--secondary').textContent == "Private") {
        console.log('private repo. set data-color-mode to dark');
        document.querySelector('html').setAttribute('data-color-mode', 'dark');
    } else {
        console.log('public repo. set data-color-mode to light');
        document.querySelector('html').setAttribute('data-color-mode', 'light');
    }
})();

I'm not that good with JavaScript, so I'd be happy if you could fork this and implement support for the Repositories tab!
(Please see also secret gist version.)

Having trouble now.
Setting html's data-color-mode doesn't update the actual page theme. :-(
(Setting the default theme to dark, it works partially, but unstable. May be needed to change apply timing.)