By default, Twitter Boostrap pads the body of mobile browsers with a media query. This makes your site look good in most cases, but works against you if you want a Jumbotron-style header. This code overrides the body padding, but retains it for container-fluid divs.

bootstrap-jumbotron-mobile.less

// Tablets and below
@media (max-width: 767px) {
  // Remove the extra padding for media queries so the Jumbotron
  // still spans the full width of the page, even in mobile browsers.
  // Instead, move the padding into the container-fluid class.
  body {
    padding-left: 0;
    padding-right: 0;
  }
  .container-fluid {
    padding-left: 20px;
    padding-right: 20px;
  }
}