JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cdn.datatables.net/1.10.2/js/jquery.dataTables.min.js"></script>
<link rel="stylesheet" href="http://cdn.datatables.net/1.10.2/css/jquery.dataTables.css">
<h3>Sub-Table by itself: does not inherit style or sorting :)</h3>
<table class='subtable'>
    <thead>
        <tr>
            <td>Project</td>
            <td>Role</td>
        </tr>
    </thead>
    <tbody>
    <tr>
        <td>Alpha</td>
        <td>Leader</td>
    </tr>
    <tr>
        <td>Beta</td>
        <td>Assistant</td>
    </tr>  
    </tbody>
</table>
<h3>DataTable including Sub-Tables: inherits unwanted styles and sorting behaviour :(</h3>
<table id="dataTable" class="row-border cell-border order-column stripe"></table>

CSS

h3 {
    color: steelblue;
}
.subtable {
    margin: 0px;
    padding: 0px;
    border: 0px;
}

.subtable td {
    margin: 0px;
    padding: 0px;
    border: 0px;
}

JavaScript

$(document).ready(function () {
	var myData = [{
			employee : "Bob Smith",
			projects : [{
					project : "Alpha",
					role : "Leader"
				}, {
					project : "Beta",
					role : "Assistant"
				}
			]
		}, {
			employee : "Tom Peterson",
			projects : [{
					project : "Alpha",
					role : "Assistant"
				}, {
					project : "Beta",
					role : "Leader"
				}
			]
		}
	];

	var myColumns = [
        {
			title : "Employee",
			data : "employee"
		}, 
        {
			title : "Projects",
			data : null,
			render : function (data, type, row, meta) {
				var subtableHtml = "<table class='subtable'>";
                subtableHtml += "<thead><tr><td>Project</td><td>Role</td></tr></thead>";
                subtableHtml += "<tbody>"
                
				for (var i = 0; i < data.projects.length; i++) {
					subtableHtml += "<tr>";
					subtableHtml += "<td>" + data.projects[i].project + "</td>";
					subtableHtml += "<td>" + data.projects[i].role + "</td>";
					subtableHtml += "</tr>";
				};
				subtableHtml += "</tbody></table>";
                return subtableHtml;
			}
		}
	];

	$('#dataTable').dataTable({
        searching: false,
        paging: false,
		data : myData,
		columns : myColumns
	});
});