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    <div class="container">
        <div class="row">
            <div class="col-md-4">Box 1</div>
            <div class="col-md-4">Box 2</div>
            <div class="col-md-4">Box 3</div>
            <div class="clearfix visible-md-block visible-lg-block"></div>
            <div class="col-md-4">Box 4</div>
            <div class="col-md-4">Box 5</div>
            <div class="col-md-4">Box 6</div>
        </div>
    </div>
</body>
</html>                                		
.col-md-4 {
    padding-top: 10px;
    padding-bottom: 10px;
    background-color: #eee;
    background-color: rgba(86,61,124,.15);
    border: 1px solid #ddd;
    border: 1px solid rgba(86,61,124,.2);
  &:nth-child(2) {
    height: 70px;
    background-color: red;
  }
}
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