Reddit UI Toggle (old ↔ sh)

Toggle between old Reddit and sh.reddit UI
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// ==UserScript==
// @name         Reddit UI Toggle (old ↔ sh)
// @license MIT
// @namespace    http://tampermonkey.net/
// @version      1.0
// @description  Toggle between old Reddit and sh.reddit UI
// @match        *://*.reddit.com/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // Create toggle button
    const btn = document.createElement('button'); // ✅ fixed
    btn.textContent = 'Toggle UI';

    btn.style.position = 'fixed';
    btn.style.bottom = '20px';
    btn.style.right = '20px';
    btn.style.zIndex = '9999';

    btn.style.width = '90px';
    btn.style.height = '32px';

    btn.style.background = '#ff4500';
    btn.style.color = '#fff';
    btn.style.border = 'none';
    btn.style.borderRadius = '6px';
    btn.style.cursor = 'pointer';

    btn.style.fontSize = '12px';
    btn.style.lineHeight = '1';

    btn.style.display = 'inline-flex';
    btn.style.alignItems = 'center';
    btn.style.justifyContent = 'center';

    btn.onclick = () => {
        const url = new URL(window.location.href);

        if (url.hostname.startsWith('old.')) {
            url.hostname = 'sh.reddit.com';
        } else if (url.hostname.startsWith('sh.')) {
            url.hostname = 'old.reddit.com';
        } else {
            // default reddit.com → go to sh
            url.hostname = 'sh.reddit.com';
        }

        window.location.href = url.toString();
    };

    document.body.appendChild(btn);
})();