A decent boilerplate for print CSS

print.css

/* TODO: Add support for page, chapter and figure counters */
/* Built with the help of https://www.smashingmagazine.com/2015/01/designing-for-print-with-css/ */

@media print {
  main {
    width: 100%; 
    margin: 0;
  }

  @page { margin: 2cm }

  body {
    font: 13pt Georgia, "Times New Roman", Times, serif;
    line-height: 1.3;
    background: #fff !important;
    color: #000;
  }

  h1 { font-size: 24pt }

  h2, h3, h4 {
    font-size: 14pt;
    margin-top: 25px;
  }
  h1, h2, h3, h4, h5, h6 {
    page-break-after:avoid; 
    page-break-inside:avoid;
  }

  a,
  blockquote { page-break-inside: avoid }

  img {
    page-break-inside:avoid; 
    page-break-after:avoid;
  }
  table, pre { page-break-inside:avoid }
  ul, ol, dl  { page-break-before:avoid }

  a:link, a:visited, a {
    background: transparent;
    color: #520;
    font-weight: bold;
    text-decoration: underline;
    text-align: left;
  }

  a[href^=http]:after {
    content: " <" attr(href) "> ";
  }

  article a[href^="#"]:after {
     content: "";
  }

  a:not(:local-link):after {
     content:" <" attr(href) "> ";
  }

  iframe, ins {
    display: none;
    width: 0 !important;
    height: 0 !important;
    overflow: hidden !important;
    line-height: 0pt !important;
    white-space: nowrap;
  }

  nav, aside {
    display: none;
  }

  body > header:before,
  body > footer:before {
    content: "Optional thank you note?";
    color: #777 !important;
    font-size: 1em;
    padding-top: 30px;
    text-align: center !important;    
  }

  p, address, li, dt, dd, blockquote {
    font-size: 100%
  }

  code, pre { font-family: mono }

  ul, ol {
    list-style: square; margin-left: 18pt;
    margin-bottom: 20pt;
  }

  li {
    line-height: 1.6em;
  }
}