================================================================================
Navbar fixed at top
-------------------

  HTML
  ----

  <nav class="navbar navbar-default navbar-fixed-top">
    <div class="container">
      ...
    </div>
  </nav>

  CSS
  ---

  body {
    padding-top: 70px; /* Default navbar height: 50px */
  }

================================================================================

Navbar fixed at bottom
----------------------

  HTML
  ----

  <nav class="navbar navbar-default navbar-fixed-bottom">
    <div class="container">
      ...
    </div>
  </nav>

  CSS
  ---

  body {
    padding-bottom: 70px;  /* Default navbar height: 50px */
  }