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HTML 

              
                <html>
<head>
    <meta charset="utf-8"/>
    <meta http-equiv="X-UA-Compatible" content=="IE=edge"/>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Responsive Bootstrap Toolkit</title>
    <link href='https://fonts.googleapis.com/css?family=Open+Sans:400,300,700' rel='stylesheet' type='text/css'>
    <!-- Include default Bootstrap stylesheet -->
    <link rel="stylesheet" type="text/css" href="https://netdna.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css"/>
</head>

<body>

    <div class="wrapper">
        <div class="site-topbar clearfix" data-compact-height="40" data-fullsize-height="60">
            <h5 class="text-uppercase">Responsive Bootstrap Toolkit</h5>
            <div class="breakpoint-alias pull-right text-center"></div>
        </div>

        <div class="container-fluid">
            <div class="row">
                <div class="col-xs-12 col-sm-8 col-md-6 col-lg-6 col-sm-push-2 col-md-push-3 col-lg-push-3">
                    <br/>
                    <br/>
                    <p>Boxes below get highlighted whenever current viewport matches their expression. Alias of current breakpoint is visible in the top right corner.</p>
                    <br/>
                    
                    <div class="comparison-boxes">
                        <div class="comparison-operator box-1">
                            &lt;=sm
                        </div>
                        <div class="comparison-operator box-2">
                            md
                        </div>
                        <div class="comparison-operator box-3">
                            &gt;md
                        </div>
                    </div>
                </div>
            </div>
        </div>

    </div>

    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
    <script src="https://rawgit.com/maciej-gurban/responsive-bootstrap-toolkit/master/dist/bootstrap-toolkit.min.js"></script>

</body>
</html>
!

CSS 

              
                /*
 * None of the CSS in this example is necessary for the base script to work properly. The only required CSS is the one shipped with Bootstrap.
 */

/* This example's styling */

@media (max-width: 767px) {
  .breakpoint-alias:before {
    content: "XS";
  }
}
@media (min-width: 768px) and (max-width: 983px) {
  .breakpoint-alias:before {
    content: "SM";
  }
}
@media (min-width: 984px) and (max-width: 1199px) {
  .breakpoint-alias:before {
    content: "MD";
  }
}
@media (min-width: 1200px) {
  .breakpoint-alias:before {
    content: "LG";
  }
}

body {
  font-family: 'Open Sans', sans-serif;
}

@media (max-width: 767px) {
  h1 {
    font-size: 20px;
  }
}
@media (min-width: 768px) and (max-width: 983px) {
  h1 {
    font-size: 24px;
  }
}
@media (min-width: 984px) and (max-width: 1199px) {
  h1 {
    font-size: 24px;
  }
}
@media (min-width: 1200px) {
  h1 {
    font-size: 30px;
  }
}

.wrapper {
  background: white;
  color: #666666;
}
.wrapper .site-topbar {
  height: 60px;
  line-height: 60px;
  vertical-align: middle;
  background: #414141;
  color: white;
  position: relative;
  vertical-align: middle;
}
.wrapper .site-topbar h5 {
  height: inherit;
  line-height: inherit;
  vertical-align: middle;
  font-weight: 300;
  margin: 0 60px 0 15px;
  vertical-align: middle;
}
.wrapper .site-topbar .breakpoint-alias {
  background-color: #238cce;
  position: absolute;
  top: 0;
  bottom: 0;
  right: 0;
  width: 60px;
  margin: auto;
}

.comparison-boxes {
  text-align: justify;
  font-size: 0.1px;
}
.comparison-boxes:after {
  content: '';
  display: inline-block;
  width: 100%;
}

.comparison-operator {
  height: 140px;
  line-height: 140px;
  vertical-align: middle;
  display: inline-block;
  background: #414141;
  color: white;
  font-size: 25px;
  text-align: center;
  width: 33%;
  min-height: 50%;
}
.comparison-operator.active {
  background: #238cce;
}

.text-uppercase {
  text-transform: uppercase;
}
!

JS 

              
                (function($, document, window, viewport){

    var highlightBox = function( className ) {
        $(className).addClass('active');
    }

    var highlightBoxes = function() {
        $('.comparison-operator').removeClass('active');

        if( viewport.is("<=sm") ) {
            highlightBox('.box-1');
        }

        if( viewport.is("md") ) {
            highlightBox('.box-2');
        }

        if( viewport.is(">md") ) {
            highlightBox('.box-3');
        }
    }

    // Executes once whole document has been loaded
    $(document).ready(function() {

        highlightBoxes();

        console.log('Current breakpoint:', viewport.current());

    });

    $(window).resize(
        viewport.changed(function(){
            highlightBoxes();

            console.log('Current breakpoint:', viewport.current());
        })
    );

})(jQuery, document, window, ResponsiveBootstrapToolkit);
!
999px

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