Greasemonkey : Add print style to stackexchange.com (SX).

Add print style to SX.user.js

// ==UserScript==
// @name         Add print style to SX
// @namespace    https://gist.github.com/kpym/0e595241caeaccefdecdb09d4186c376
// @version      0.1
// @description  This script inject @media print CSS to SX websites
// @author       kpym
// @match        http*://*.stackexchange.com/*
// @grant        GM_addStyle
// ==/UserScript==
/* jshint -W097 */
'use strict';

// ------------------------------------------
// CSS part injected in the page
GM_addStyle(" \
@media print { \
  * {     \
    visibility: hidden; \
  } \
  #content * {     \
    visibility: visible; \
  } \
  header, #left-sidebar, #sidebar, form, .bottom-notice, .comments-link, .aside-cta {     \
    display: none; \
  } \
  #mainbar {     \
    width: 100%; \
  } \
  div.post-text {     \
    page-break-inside: avoid; \
  } \
} \
");