Autoiskola Dark Mode

Dark theme for a driver school webpage

// ==UserScript==
// @name        Autoiskola Dark Mode
// @namespace    http://tampermonkey.net/
// @version      0.22
// @description  Dark theme for a driver school webpage
// @author       torturtle
// @match        https://servisi.euprava.gov.rs/autoskole/*
// @grant        none
// ==/UserScript==

var g = document.getElementsByClassName('page-content')[0];
if (g) {
    g.style.background = "black";
    g.style.color = "white";
    g.style.minHeight = "100vh";
}
var c = document.getElementById("examNavigationBar");
if (c) {
    c.style.background = "#333";
    c.style.border = "2px solid #999";
    c.style.borderRadius = "20px";
}
var m = document.getElementById("main-container");
if (m) {
    m.style.background = "black";
    m.style.color = "white";
}
var u = document.getElementsByClassName("form-actions")[0];
if (u && u.id != "examNavigationBar") {
    u.style.background = "black";
    u.style.height = "50vh";
}
var k = document.getElementById("divOuter");
if (k) {
    k.style.background = "black";
}
var p = document.getElementById("divConfirmStart");
if (p) {
    p.style.background = "linear-gradient(to bottom right, #111, #444)";
}
var q = document.getElementById("divChooseLang");
if (q) {
    q.style.background = "linear-gradient(to bottom right, #111, #444)";
}
var y = document.getElementsByTagName("table")[0];
if (y) {
    y.classList.remove('table-hover');
    y.classList.remove('table-striped');
}
var userdata = document.getElementsByClassName("profile-info-value");
for (var i = 0; i < userdata.length; i++) {
    userdata[i].style.color = "black";
}
var bigg = document.createElement('div');
bigg.style.background = "#530";
bigg.style.opacity = "0.1";
bigg.style.position = "fixed";
bigg.style.width = "100vw";
bigg.style.height = "100vh";
bigg.style.top = "0";
bigg.style.left = "0";
bigg.id = "bigg";
bigg.style.zIndex = "874586536";
bigg.style.pointerEvents = "none";
document.body.appendChild(bigg);
var cont = document.createElement("span");
cont.style.display = "block";
cont.style.padding = "5px";
cont.style.background = "rgba(200,200,0,0.5)";
cont.style.color = "white";
cont.style.border = "3px solid white";
cont.style.position = "fixed";
cont.style.right = "2px";
cont.style.fontWeight = "bold";
cont.style.userSelect = "none";
cont.style.cursor = "pointer";
cont.style.borderRadius = "5px";
cont.style.bottom = "2px";
cont.innerHTML = "Change filter (0.1)";
document.body.appendChild(cont);
cont.addEventListener("click",function () {
	var o = parseFloat(bigg.style.opacity);
	o += 0.1;
	o = o.toFixed(1);
	if (o > 0.7) { o = 0; }
	bigg.style.opacity = o + "";
	console.log(bigg.style.opacity);
	cont.innerHTML = "Change filter (" + o + ")";
});