Dividir cabecera de Blogger en 3 partes horizontales

<div id="content-atas">
<b:section class='content-atas section' id='content-atas1' preferred='yes'/>
</div>

<div class='region-inner tabs-inner' id='content-atas' style='text-align:center'>

<div id='crosscol0' style='text-align: center; padding: 5px;'>
<b:section class='tabs' id='crosscol-superior' preferred='yes'/>
</div>

<div id='crosscol1' style='width: 33%; float: left; margin:0; padding: 5px;'>
<b:section class='tabs' id='cross1' preferred='yes' style='float:left;'/>
</div>

<div id='crosscol2' style='width: 33%; float: left; margin:0; padding: 5px;'>
<b:section class='tabs' id='cross2' preferred='yes' style='float:left;'/>
</div>

<div id='crosscol3' style='width: 33%; float: right; margin:0; padding: 5px;'>
<b:section class='tabs' id='cross3' preferred='yes' style='float:right;'/>
</div>

<div style='clear:both;'/>
</div>