JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://v4-alpha.getbootstrap.com/dist/css/bootstrap.css">
<script src="https://code.jquery.com/jquery-3.1.1.slim.min.js"></script>
<script src="https://v4-alpha.getbootstrap.com/dist/js/bootstrap.min.js"></script>
<div class="container">
  <div class="row">
    <div class="col-12 col-md-12 pull-md-3 bd-content">
      <div class="bd-example">
        <div class="d-flex bd-highlight mb-3" style="height: 100px">
          <div class="p-2 bd-highlight">Flex item</div>
          <div class="align-self-start p-2 bd-highlight">Aligned flex item</div>
          <div class="p-2 bd-highlight">Flex item</div>
        </div>
        <div class="d-flex bd-highlight mb-3" style="height: 100px">
          <div class="p-2 bd-highlight">Flex item</div>
          <div class="align-self-end p-2 bd-highlight">Aligned flex item</div>
          <div class="p-2 bd-highlight">Flex item</div>
        </div>
        <div class="d-flex bd-highlight mb-3" style="height: 100px">
          <div class="p-2 bd-highlight">Flex item</div>
          <div class="align-self-center p-2 bd-highlight">Aligned flex item</div>
          <div class="p-2 bd-highlight">Flex item</div>
        </div>
        <div class="d-flex bd-highlight mb-3" style="height: 100px">
          <div class="p-2 bd-highlight">Flex item</div>
          <div class="align-self-baseline p-2 bd-highlight">Aligned flex item</div>
          <div class="p-2 bd-highlight">Flex item</div>
        </div>
        <div class="d-flex bd-highlight mb-3" style="height: 100px">
          <div class="p-2 bd-highlight">Flex item</div>
          <div class="align-self-stretch p-2 bd-highlight">Aligned flex item</div>
          <div class="p-2 bd-highlight">Flex item</div>
        </div>

        <div class="d-flex justify-content-start bd-highlight mb-3">
          <div class="p-2 bd-highlight">Flex item</div>
          <div class="p-2 bd-highlight">Flex item</div>
          <div class="p-2 bd-highlight">Flex...

CSS

.bd-example {
  background-color: #ccc;
}

.p-2 {
  background-color: grey;
  color: white;
}

body .mb-3 {
  border-top: 2px solid white;
  border-bottom: 2px solid white;
}

JavaScript

(function($) {
  $(document).ready(function() {
    $('.mb-3').each(function() {
      var style = $(this).attr('style');
      $(this).attr('style', style + '; margin-bottom: 0 !important;');
      //$(this).css('margin-bottom', '0');
    });
  });

})(jQuery);