Hi MK18,
This should help you out;
Keep your CSS script in a compose action:

Then add the output of the compose before your HTML table like this:

Output:

If this solved your case, please mark it as a solution.
Let me know if you have any further issues.
Br
Heartholme
Additional information:
CSS script:
<style>
table{
font-family: Arial, Helvetica, sans-serif;
background-color: #EEEEEE;
border-collapse:collapse;
width: 100%;
}
Table td, table th {
border: 1px solid #ddd;
padding: 3px 3px;
}
HTML table in compose:
<table>
<tbody>
<tr>
<td>Equipment ID </td>
<td> Numberlocation</td>
<td>Eqiument name</td>
<td>Due date</td>
</tr>
<tr>
<td> Q0003</td>
<td>QA</td>
<td>Chroma Meter</td>
<td>empty</td>
</tr>
</tbody>
</table>
<p> </p>