Bring back red subscribe button

What have you done Suzan!?

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(У мене вже є менеджер скриптів, дайте мені встановити його!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         Bring back red subscribe button
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  What have you done Suzan!?
// @author       Haddle
// @match        *://www.youtube.com/*\
// @license MIT
// ==/UserScript==

(function() {
    'use strict';
    var changeColour = function(){
        var feedback_buttons= document.getElementsByClassName("yt-spec-button-shape-next yt-spec-button-shape-next--filled yt-spec-button-shape-next--mono yt-spec-button-shape-next--size-m");
        var feedback_text = document.getElementsByClassName("yt-core-attributed-string yt-core-attributed-string--white-space-no-wrap");
        for(var i=0;i<feedback_buttons.length;i++){feedback_buttons[i].style="background-color:#f00"};
        for(i=0;i<feedback_text.length;i++){feedback_text[i].style="color:#fff"};
        console.log("[Red Sub Button]: changed")
    }
    window.onload = changeColour
})();