Ok, try this,
Open your theme/style.css, and find;
.tableb {
background: #EFEFEF ;
padding-top: 3px;
padding-right: 10px;
padding-bottom: 3px;
padding-left: 10px;
}
Now create a copy of this, then edit it to call it tableb1, and change the colour code to that you want. Paste it immediately under the other code.
Now open your theme theme.php, and find;
<!-- BEGIN catrow_noalb -->
<tr>
<td class="tableb" colspan="3"><table border="0" ><tr><td>{CAT_THUMB}</td><td><span class="catlink"><b>{CAT_TITLE}</b></span>{CAT_DESC}</td></tr></table></td>
</tr>
<!-- END catrow_noalb -->
<!-- BEGIN catrow -->
<tr>
<td class="tableb"><table border="0"><tr><td>{CAT_THUMB}</td><td><span class="catlink"><b>{CAT_TITLE}</b></span>{CAT_DESC}</td></tr></table></td>
<td class="tableb" align="center">{ALB_COUNT}</td>
<td class="tableb" align="center">{PIC_COUNT}</td>
</tr>
<!--if (isset(CAT_ALBUMS)){-->
<tr>
<td class="tableb" colspan=3>{CAT_ALBUMS}</td>
</tr><!--};-->
<!-- END catrow -->
Now change that to this;
<!-- BEGIN catrow_noalb -->
<tr>
<td class="tableb1" colspan="3"><table border="0" ><tr><td>{CAT_THUMB}</td><td><span class="catlink"><b>{CAT_TITLE}</b></span>{CAT_DESC}</td></tr></table></td>
</tr>
<!-- END catrow_noalb -->
<!-- BEGIN catrow -->
<tr>
<td class="tableb1"><table border="0"><tr><td>{CAT_THUMB}</td><td><span class="catlink"><b>{CAT_TITLE}</b></span>{CAT_DESC}</td></tr></table></td>
<td class="tableb1" align="center">{ALB_COUNT}</td>
<td class="tableb1" align="center">{PIC_COUNT}</td>
</tr>
<!--if (isset(CAT_ALBUMS)){-->
<tr>
<td class="tableb" colspan=3>{CAT_ALBUMS}</td>
</tr><!--};-->
<!-- END catrow -->