css - Remove a margin in the top of a PrimeFaces dataGrid -

i have p:datagrid in responsive mode. can not understand why there “margin” in top of datagrid before datagrid content, , can not remove :

http://www.zimagez.com/zimage/margindatagrid.php

i have tried set negative margin-top on ui-datagrid-column class, removes margin third panel (the list contains 4 objects).

<p:datagrid  value="#{secb.secus}" var="sec" layout="grid" columns="2" styleclass="datagrid-secuedit">       <p:panel>                <h:outputtext value="panelx"/>       </p:panel>    </p:datagrid>  .datagrid-secuedit{ border: 2px solid green; width: 585px; margin: 0 auto; }  .ui-datagrid-column{ margin-top: -25px !important; } 

here generated html :

<div id="main">  <div id="j_idt174" class="ui-datagrid ui-widget datagrid-secuedit">     <div id="j_idt174_content" class="ui-datagrid-content ui-widget-content ui-grid ui-grid-responsive">         <div class="ui-grid-row">             <div class="ui-datagrid-column ui-grid-col-6">                 <div id="j_idt174:0:j_idt31" class="ui-panel ui-widget ui-widget-content ui-corner-all" data-widget="widget_j_idt174_0_j_idt31">                     <div id="j_idt174:0:j_idt31_content" class="ui-panel-content ui-widget-content">panelx</div>                 </div>                 <script id="j_idt174:0:j_idt31_s" type="text/javascript">primefaces.cw("panel", "widget_j_idt174_0_j_idt31", {id: "j_idt174:0:j_idt31"});</script>             </div>             <div class="ui-datagrid-column ui-grid-col-6">                 <div id="j_idt174:1:j_idt31" class="ui-panel ui-widget ui-widget-content ui-corner-all" data-widget="widget_j_idt174_1_j_idt31">                     <div id="j_idt174:1:j_idt31_content" class="ui-panel-content ui-widget-content">panelx</div>                 </div><script id="j_idt174:1:j_idt31_s" type="text/javascript">primefaces.cw("panel", "widget_j_idt174_1_j_idt31", {id: "j_idt174:1:j_idt31"});</script>             </div>         </div>         <div class="ui-grid-row">             <div class="ui-datagrid-column ui-grid-col-6">                 <div id="j_idt174:2:j_idt31" class="ui-panel ui-widget ui-widget-content ui-corner-all" data-widget="widget_j_idt174_2_j_idt31">                     <div id="j_idt174:2:j_idt31_content" class="ui-panel-content ui-widget-content">panelx</div>                 </div>                 <script id="j_idt174:2:j_idt31_s" type="text/javascript">primefaces.cw("panel", "widget_j_idt174_2_j_idt31", {id: "j_idt174:2:j_idt31"});</script>             </div>             <div class="ui-datagrid-column ui-grid-col-6">                 <div id="j_idt174:3:j_idt31" class="ui-panel ui-widget ui-widget-content ui-corner-all" data-widget="widget_j_idt174_3_j_idt31">                     <div id="j_idt174:3:j_idt31_content" class="ui-panel-content ui-widget-content">panelx</div>                 </div>                 <script id="j_idt174:3:j_idt31_s" type="text/javascript">primefaces.cw("panel", "widget_j_idt174_3_j_idt31", {id: "j_idt174:3:j_idt31"});</script>             </div>         </div>     </div> </div> <script id="j_idt174_s" type="text/javascript">primefaces.cw("datagrid", "widget_j_idt174", {id: "j_idt174"});</script> <script type="text/javascript" src="/iso/javax.faces.resource/respond.min.js.xhtml?ln=js"></script>