[CSS] สอบถามครับ สงสัยว่าทำไม มันถึงเว้น ว่างไว้อย่างนี้ครับ ดังรูปครับ

<div class="clearfix visible-xs-block"></div>
				<div class="col-xs-6 col-sm-3 col-md-2">
					<a href="#" class="magnifier" data-toggle="modal" data-target=".box15">
						<img class="img-responsive" style="margin: 0 auto;clear:both;"alt="" src="img/vians_action/vians-action-parking_100px.png">
					</a>
					<p><br></p>
					<div class="modal fade box15" tabindex="-1" role="dialog" aria-labelledby="myLargeModalLabel" aria-hidden="true">
  						<div class="modal-dialog">
    						<div class="modal-content">
      							<img class="img-responsive" style="margin: 0 auto;clear:both;"src="img/vians_action/vians-action-parking_300px.png" alt="ViAns on the bike">
      							<div class="modal-footer">
          							<button type="button" class="btn btn-primary" data-dismiss="modal">Close</button>
        						</div>
    						</div>
  						</div>
					</div>
				</div>
				
				<div class="col-xs-6 col-sm-3 col-md-2">
					<a href="#" class="magnifier" data-toggle="modal" data-target=".box16">
						<img class="img-responsive" style="margin: 0 auto;clear:both;"alt="" src="img/vians_action/vians-action-pay_everywere_100px.png">
					</a>
					<p><br></p>
					<div class="modal fade box16" tabindex="-1" role="dialog" aria-labelledby="myLargeModalLabel" aria-hidden="true">
  						<div class="modal-dialog">
    						<div class="modal-content">
      							<img class="img-responsive" style="margin: 0 auto;clear:both;"src="img/vians_action/vians-action-pay_everywere_300px.png" alt="ViAns on the bike">
      							<div class="modal-footer">
          							<button type="button" class="btn btn-primary" data-dismiss="modal">Close</button>
        						</div>
    						</div>
  						</div>
					</div>
				</div>
				<div class="clearfix visible-xs-block"></div>
				<div class="col-xs-6 col-sm-4 col-sm-3 col-md-2"> 									
					<a href="#" class="magnifier"data-toggle="modal" data-target=".box17">
						<img class="img-responsive" style="margin: 0 auto;clear:both;"alt="" src="img/vians_action/vians-action-taxi_100px.png">
					</a>
					<p><br></p>
					<div class="modal fade box17" tabindex="-1" role="dialog" aria-labelledby="myLargeModalLabel" aria-hidden="true">
  						<div class="modal-dialog">
    						<div class="modal-content">
      							<img class="img-responsive" style="margin: 0 auto;clear:both;"src="img/vians_action/vians-action-taxi_300px.png" alt="ViAns on the bike">
      							<div class="modal-footer">
          							<button type="button" class="btn btn-primary" data-dismiss="modal">Close</button>
        						</div>
    						</div>
  						</div>
					</div>
				</div>
				<div class="col-xs-6 col-sm-3 col-md-2">
					<a href="#" class="magnifier" data-toggle="modal" data-target=".box18">
						<img class="img-responsive" style="margin: 0 auto;clear:both;"alt="" src="img/vians_action/vians-action-topup_100px.png">
					</a>
					<p><br></p>
					<div class="modal fade box18" tabindex="-1" role="dialog" aria-labelledby="myLargeModalLabel" aria-hidden="true">
  						<div class="modal-dialog">
    						<div class="modal-content">
      							<img class="img-responsive" style="margin: 0 auto;clear:both;"src="img/vians_action/vians-action-topup_300px.png" alt="ViAns on the bike">
      							<div class="modal-footer">
          							<button type="button" class="btn btn-primary" data-dismiss="modal">Close</button>
        						</div>
    						</div>
  						</div>
					</div>
				</div>
				<div class="clearfix visible-xs-block"></div>
			</div>
			<div class="col-md-12"><br></div>
			<div class="col-md-12">
				<div class="col-xs-6 col-sm-3 col-md-2">
					<a href="#" class="magnifier" data-toggle="modal" data-target=".box19">
						<img class="img-responsive" style="margin: 0 auto;clear:both;"alt="" src="img/vians_action/vians-action-train_100px.png">
					</a>
					<div class="modal fade box19" tabindex="-1" role="dialog" aria-labelledby="myLargeModalLabel" aria-hidden="true">
  						<div class="modal-dialog">
    						<div class="modal-content">
      							<img class="img-responsive" style="margin: 0 auto;clear:both;"src="img/vians_action/vians-action-train_300px.png" alt="ViAns on the bike">
      							<div class="modal-footer">
          							<button type="button" class="btn btn-primary" data-dismiss="modal">Close</button>
        						</div>
    						</div>
  						</div>
					</div>
				</div>
			</div>