A UserScript to customize GitHub's tab size

github_tab_size.js

// ==UserScript==
// @name         Github Tab Size
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Changes GitHub's tab size
// @author       DaCurse
// @match        https://github.com/*
// @icon         https://github.githubassets.com/favicons/favicon.svg
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    const size = 2;
    const style = document.createElement('style');
    style.innerHTML = `
    .tab-size {
      -webkit-tab-size: ${size} !important;
      -moz-tab-size: ${size} !important;
      -o-tab-size: ${size} !important;
      tab-size: ${size} !important;
    }`;

    document.head.appendChild(style);
})();