YouTube Dark Mode Toggle

Adds a bottom-left toggle button for YouTube dark/light text mode
换行
// ==UserScript==
// @name         YouTube Dark Mode Toggle
// @namespace    http://tampermonkey.net/
// @version      1.2
// @description  Adds a bottom-left toggle button for YouTube dark/light text mode
// @author       You
// @match        https://www.youtube.com/*
// @grant        none
// @license      MIT
// ==/UserScript==

(function() {
    'use strict';

    // Wait until YouTube body exists
    function addToggleButton() {
        if (document.body.querySelector('#yt-darkmode-toggle')) return; // already added

        const toggle = document.createElement('button');
        toggle.id = 'yt-darkmode-toggle';
        toggle.innerText = 'Toggle Dark Mode';
        toggle.style.position = 'fixed';
        toggle.style.bottom = '10px';
        toggle.style.left = '10px';
        toggle.style.zIndex = '9999';
        toggle.style.padding = '10px';
        toggle.style.backgroundColor = '#000';
        toggle.style.color = '#fff';
        toggle.style.border = 'none';
        toggle.style.borderRadius = '5px';
        toggle.style.cursor = 'pointer';
        document.body.appendChild(toggle);

        let darkMode = false;

        toggle.addEventListener('click', () => {
            darkMode = !darkMode;

            const textColor = darkMode ? '#fff' : '#000';
            const bgColor = darkMode ? '#111' : '#fff';

            document.body.style.backgroundColor = bgColor;
            document.body.style.color = textColor;

            document.querySelectorAll('*').forEach(el => {
                if (el.tagName !== 'SCRIPT' && el.tagName !== 'STYLE') {
                    el.style.color = textColor;
                }
            });
        });
    }

    // Try adding the button every second until it works
    const interval = setInterval(() => {
        if (document.body) {
            addToggleButton();
            clearInterval(interval);
        }
    }, 1000);

})();