Linux.do Watermark Neo

Force watermark username to 'neo'
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// ==UserScript==
// @name         Linux.do Watermark Neo
// @namespace    http://tampermonkey.net/
// @description  Force watermark username to 'neo'
// @version      1.1
// @match        https://linux.do/*
// @icon         https://linux.do/favicon.ico
// @grant        unsafeWindow
// @run-at       document-start
// @license      MIT
// ==/UserScript==

(function() {
    'use strict';

    const rawAttach = Element.prototype.attachShadow;
    Element.prototype.attachShadow = function(init) {
        if (init && init.mode === 'closed') {
            init.mode = 'open';
            const shadowRoot = rawAttach.call(this, init);
            const style = document.createElement('style');
            style.textContent = 'div { opacity: 0 !important; visibility: hidden !important; pointer-events: none !important; }';
            shadowRoot.appendChild(style);
            return shadowRoot;
        }
        return rawAttach.call(this, init);
    };

    const CONFIG = {
        text: "neo",
        id: "ld-wm-neo-force",
        density: 130,
        intensity: 2,
        angle: -25,
        font: "bold 15px sans-serif"
    };

    function generateWatermark() {
        if (document.getElementById(CONFIG.id)) return;

        const dpr = window.devicePixelRatio || 1;
        const canvas = document.createElement("canvas");
        const size = CONFIG.density * dpr;

        canvas.width = size;
        canvas.height = size;

        const ctx = canvas.getContext("2d");
        ctx.scale(dpr, dpr);
        ctx.translate(CONFIG.density / 2, CONFIG.density / 2);
        ctx.rotate(CONFIG.angle * Math.PI / 180);
        ctx.font = CONFIG.font;
        ctx.textAlign = "center";
        ctx.textBaseline = "middle";
        ctx.fillStyle = `rgb(${CONFIG.intensity}, ${CONFIG.intensity}, ${CONFIG.intensity})`;
        ctx.fillText(`@${CONFIG.text}`, 0, 0);

        const div = document.createElement("div");
        div.id = CONFIG.id;
        div.style.cssText = `
            position: fixed;
            top: 0;
            left: 0;
            width: 100vw;
            height: 100vh;
            z-index: 2147483647;
            pointer-events: none;
            background-image: url(${canvas.toDataURL("image/png")});
            background-repeat: repeat;
            background-size: ${CONFIG.density}px;
            mix-blend-mode: difference;
            opacity: 1;
        `;
        document.body.appendChild(div);
    }

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', generateWatermark);
    } else {
        generateWatermark();
    }
})();