Bootstrap 4 examples as Pug templates

bootstrap-starter-nav.pug

doctype html
html(lang="en")
  head
    meta(charset="utf-8")
    meta(name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no")
    title Bootstrap 4 Starter With Nav
    link(rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous")
  body
    nav.navbar.navbar-expand-md.navbar-dark.bg-dark.fixed-top
      a.navbar-brand(href="#") BRAND
      button.navbar-toggler(type="button" data-toggle="collapse" data-target="#main-navbar")
        span.navbar-toggler-icon
      #main-navbar.collapse.navbar-collapse
        ul.navbar-nav.mr-auto
          li.nav-item.active
            a.nav-link(href="#") Link 1
          li.nav-item
            a.nav-link(href="#") Link 2
          li.nav-item
            a.nav-link(href="#") Link 3
          li.nav-item.dropdown
            a#dropdown01.nav-link.dropdown-toggle(href="#" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Dropdown
            .dropdown-menu
              a.dropdown-item(href="#") Action 1
              a.dropdown-item(href="#") Action 2
              a.dropdown-item(href="#") Action 3
        form.form-inline.my-2.my-lg-0
          input.form-control.mr-sm-2(type="text" placeholder="Input...")
          button.btn.btn-primary.my-2.my-sm-0(type="submit") OK
    main.container(role="main" style="padding: 60px;")
        h1.text-center Bootstrap starter template
        p.lead.text-center This document as a way to quickly start a new Bootstrap 4 project.
        p.text-center Build upon this barebones HTML document.
    script(src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous")
    script(src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous")
    script(src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous")

bootstrap-starter.pug

doctype html
html(lang="en")
  head
    meta(charset="utf-8")
    meta(name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no")
    link(rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous")
    title Bootstrap 4 Starter
  body
    main.container
      p.text-center This is a very basic Bootstrap 4 starting point.
    script(src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous")
    script(src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous")
    script(src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous")