How do you add a css border to a single field on a table

I would like to show the full border selectively for an individual column/row on my table.

For records that the users need to submit to an approval process I am highlighting the row like so

table.nx-skootable-data > tbody > tr.approvalissues-row > td {

JS render snippet:
if(row.Needs_Approval__c) {

My next goal is to highlight the individual field that is causing the record to require approval by putting a border around it.

I’ve tried doing something similar to above:

using basically the same CSS format
table.nx-skootable-data > tbody > tr > td.approvalNeededBorder {
    border-width: 2px; 
    border-color: Black;

but this does not work…


Does the required field change on a case by case basis or is it always the same field? 

No change, for each row the need for approval is triggered by one of two fields that are both displayed. I have render snippets for both of them, I just need to get the css worked out

Got it figured out

.approvalBorder {
    border-color: black;
    border-style: solid;

JS render snippet change: