dark_chrome_pdf_reader_tampermonkey.js

// ==UserScript==
// @name         DARK PDF
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  dark theme for chrome pdf using L butotn on top
// @author       Plasmoxy
// @include      file:///*
// @icon         https://www.google.com/s2/favicons?domain=undefined.
// @grant        none
// ==/UserScript==

let vals = [0, 25, 50, 60, 70, 80, 90, 100]
let vali = 0

window.d = function(widthPercent) {
    if (document.getElementById("cover")) document.getElementById("cover").remove();
    let cover = document.createElement("div");
    cover.id = "cover";
    let rest = 100 - widthPercent;
    let left = rest / 2 - 0.5;
    let css = `box-sizing: border-box; position: fixed;pointer-events: none;top: 0;left: ${left}vw;width: ${widthPercent}vw;height: 100vh;background-color: #fafafa;mix-blend-mode: difference;z-index: 1;`;
    cover.setAttribute("style", css);
    document.body.appendChild(cover);
    console.log("darkened to " + widthPercent);
}

let b = document.createElement("button")
b.onclick = () => {
    vali = (vali + 1) % vals.length;
    window.d(vals[vali]);
}
b.setAttribute("style", "position: fixed; top: 0; left: 0; z-index: 3;");
b.innerText = "L"
document.body.appendChild(b);

console.log("ddark");