<!-- 

/* adds some margin below the link sets  */
.navbar .dropdown-menu div[class*="col"] {
   margin-bottom:1rem;
}

.navbar .dropdown-menu {
  border:none;
  background-color:#0060c8!important;
}

/* breakpoint and up - mega dropdown styles */
@media screen and (min-width: 992px) {
  
  /* remove the padding from the navbar so the dropdown hover state is not broken */
.navbar {
  padding-top:0px;
  padding-bottom:0px;
}

/* remove the padding from the nav-item and add some margin to give some breathing room on hovers */
.navbar .nav-item {
  padding:.5rem .5rem;
  margin:0 .25rem;
}

/* makes the dropdown full width  */
.navbar .dropdown {position:static;}

.navbar .dropdown-menu {
  width:100%;
  left:0;
  right:0;
/*  height of nav-item  */
  top:45px;
  
  display:block;
  visibility: hidden;
  opacity: 0;
  transition: visibility 0s, opacity 0.3s linear;
  
}
  
 

  
  /* shows the dropdown menu on hover */
.navbar .dropdown:hover .dropdown-menu, .navbar .dropdown .dropdown-menu:hover {
  display:block;
  visibility: visible;
  opacity: 1;
  transition: visibility 0s, opacity 0.3s linear;
}
  
  .navbar .dropdown-menu {
    border: 1px solid rgba(0,0,0,.15);
    background-color: #fff;
  }

}


-->


<nav class="navbar navbar-default">
  <div class="container">
    <!-- Brand and toggle get grouped for better mobile display -->
    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <a class="navbar-brand" href="#">Brand</a>
    </div>

    <!-- Collect the nav links, forms, and other content for toggling -->
    <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
      <ul class="nav navbar-nav">
        <li class="active"><a href="#">Link <span class="sr-only">(current)</span></a></li>
        <li class="dropdown">
          <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Dropdown <span class="caret"></span></a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">

          
          <div class="container">
            <div class="row">
              <div class="col col-xs-6 col-md-3">
                <ul class="nav flex-column">
                <li class="nav-item">
                  <span class="nav-link text-bold">Category</span>
                </li>
                <li class="nav-item">
                  <a class="nav-link active" href="#">Active</a>
                </li>
                <li class="nav-item">
                  <a class="nav-link" href="#">Link item</a>
                </li>
                <li class="nav-item">
                  <a class="nav-link" href="#">Link item</a>
                </li>
              </ul>
              </div>
              <!-- /.col  -->
              
              <div class="col col-xs-6 col-md-3">
                <ul class="nav flex-column">
                <li class="nav-item">
                  <span class="nav-link text-bold">Category</span>
                </li>
                <li class="nav-item">
                  <a class="nav-link active" href="#">Active</a>
                </li>
                <li class="nav-item">
                  <a class="nav-link" href="#">Link item</a>
                </li>
                <li class="nav-item">
                  <a class="nav-link" href="#">Link item</a>
                </li>
              </ul>
              </div>
              <!-- /.col  -->
              
              <div class="col col-sm-6 col-md-3">
                <ul class="nav flex-column">
                <li class="nav-item">
                  <span class="nav-link text-bold">Category</span>
                </li>
                <li class="nav-item">
                  <a class="nav-link active" href="#">Active</a>
                </li>
                <li class="nav-item">
                  <a class="nav-link" href="#">Link item</a>
                </li>
                <li class="nav-item">
                  <a class="nav-link" href="#">Link item</a>
                </li>
              </ul>
              </div>
              <!-- /.col  -->
              
              
                <div class="col col-xs-6 col-md-3">
                <ul class="nav flex-column">
                <li class="nav-item">
                  <span class="nav-link text-bold">Category</span>
                </li>
                <li class="nav-item">
                  <a class="nav-link active" href="#">Active</a>
                </li>
                <li class="nav-item">
                  <a class="nav-link" href="#">Link item</a>
                </li>
                <li class="nav-item">
                  <a class="nav-link" href="#">Link item</a>
                </li>
              </ul>
              </div>
              <!-- /.col  -->

              
            </div>
          </div>
          <!--  /.container  -->


        </div>
        </li>
      </ul>
      <form class="navbar-form navbar-right">
        <div class="form-group">
          <input type="text" class="form-control" placeholder="Search">
        </div>
        <button type="submit" class="btn btn-default">Submit</button>
      </form>

    </div><!-- /.navbar-collapse -->
  </div><!-- /.container-fluid -->
</nav>

.navbar-nav li>span {
    position: relative;
    display: block;
    padding: 10px 15px;
    font-weight:bold;
}

/* adds some margin below the link sets  */
.navbar .dropdown-menu div[class*="col"] {
   margin-bottom:1rem;
}



/* breakpoint and up - mega dropdown styles */
@media screen and (min-width: 767px) {
  
  /* remove the padding from the navbar so the dropdown hover state is not broken */
.navbar {
  padding-top:0px;
  padding-bottom:0px;
}

/* remove the padding from the nav-item and add some margin to give some breathing room on hovers */
.navbar .nav-item {
  padding:.5rem .5rem;
  margin:0 .25rem;
}

  
/* makes the dropdown full width  */
.navbar .dropdown {position:static;}

  
.navbar .dropdown-menu {
  width:100%;
  left:0;
  right:0;
/*  height of nav-item  */
  top:45px;
  
  display:block;
  visibility: hidden;
  opacity: 0;
  transition: visibility 0s, opacity 0.3s linear;
  
}
  
 

  
  /* shows the dropdown menu on hover */
.navbar .dropdown:hover .dropdown-menu, .navbar .dropdown .dropdown-menu:hover {
  display:block;
  visibility: visible;
  opacity: 1;
  transition: visibility 0s, opacity 0.3s linear;
}
  
  .navbar .dropdown-menu {
    border: 1px solid rgba(0,0,0,.15);
    background-color: #fff;
  }

}
$(document).ready(function() {
 // executes when HTML-Document is loaded and DOM is ready

// breakpoint and up  
$(window).resize(function(){
	if ($(window).width() >= 980){	

      // when you hover a toggle show its dropdown menu
      $(".navbar .dropdown-toggle").hover(function () {
         $(this).parent().toggleClass("show");
         $(this).parent().find(".dropdown-menu").toggleClass("show"); 
       });

        // hide the menu when the mouse leaves the dropdown
      $( ".navbar .dropdown-menu" ).mouseleave(function() {
        $(this).removeClass("show");  
      });
  
		// do something here
	}	
});  
  
  

// document ready  
});

External CSS

  1. https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js
  2. https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js