Without getting into the why's and why-not's of using tables, you would style the borders of individual <td> tags with css either directly with a style attribute, or by adding a class to the cell...
<td style="border-left:1px solid #000000;border-right:2px solid #ffffff;border-top:3px solid blue;border-bottom:5px solid orange;">
or the much better approach, with a class...
.yourclass {
border-left:1px solid #000000;
border-right:2px solid #ffffff;
border-top:3px solid blue;
border-bottom:5px solid orange;
}
The html would be...
<td class="yourclass">
