<h:head>

 <style type="text/css">
        boton {
           border-radius: 5px;

        }
    </style>

</h:head>
<h:body>
    <h:form>

        <br></br>
        <h:panelGrid id="panelButtons" columns="3" style="text-align:center;" width="90%">
            <p:commandButton id="boton" value="Empleados"   styleClass="ui-priority-primary" update="dlg1" oncomplete="PF('dlg1').show();" />
        </h:panelGrid>