To avoid the gaps between cells I would modify Rons code to this:
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width,initial-scale=1.0">
<title>restyled table</title>
<style type="text/css">
.table-beneficiary h2{margin:0}
.table-beneficiary,.table-beneficiary td{
-webkit-box-sizing:border-box;
-moz-box-sizing:border-box;
box-sizing:border-box;
}
.table-beneficiary {
width:100%;
border-collapse:separate;
border-spacing:0;
border:1px solid red;
position:relative;
}
.table-beneficiary td {
padding:10px;
width:auto!important;
}
.table-beneficiary td.light:only-child{background:blue;color:#fff;}
.table-beneficiary tr + tr td:first-child:after {
content:"";
position:absolute;
display:block;
left:10px;
right:10px;
margin:10px 0 0;
border-bottom:1px solid lightgray;
}
.table-beneficiary tr:last-child td:after {visibility:hidden}
</style>
</head>
<body>
<table class="table-beneficiary" width="100%" border="0" cellspacing="0" cellpadding="3">
<tbody>
<tr>
<td class="light" colspan="3" style="padding-left:10px;width:100%"><h2>Report Class</h2></td>
</tr>
<tr>
<td width=30% style="padding-left:10px;">Administrative</td>
<td width="10%" valign="middle" style="text-align:right;"><input class="button modify" type="button" value="modify" >
<input class="button delete" type="button" value="delete"></td>
</tr>
<tr>
<td width=30% style="padding-left:10px;">Administrative</td>
<td width="10%" valign="middle" style="text-align:right;"><input class="button modify" type="button" value="modify" >
<input class="button delete" type="button" value="delete"></td>
</tr>
<tr>
<td width=30% style="padding-left:10px;">Administrative</td>
<td width="10%" valign="middle" style="text-align:right;"><input class="button modify" type="button" value="modify" >
<input class="button delete" type="button" value="delete"></td>
</tr>
</tbody>
</table>
</body>
</html>