Thanks Berny, I tried to integrate your script to mine but it did not work. I think I did it wrong and it didn't do well.
<script>https://code.jquery.com/jquery-1.10.2.js"></script>
<mail_script>printAttachments();</mail_script>
<table width="75%" style='display:block; background-color:#CCECFF;border-width:1px;border-style:solid;border-color:<mail_script>template.print(gs.getProperty('css.base.color'));</mail_script>'>
<tr><td>
<b>${sysapproval} requires your Authorisation. </b>
<mail_script>
if (!current.u_reason.nil())
template.print("Approval Reason: " + current.u_reason);
</mail_script>
<hr/>
1. Click approve or decline
<blockquote><font style="background-color: palegreen;" color='palegreen'>aa<font size='5' color='green'> ✓</font>${mailto:mailto.approval}aa</font></blockquote>
<blockquote><font style="background-color: pink;" color='pink'>aa<font size='5' color='red'>✗</font> ${mailto:mailto.rejection}aaa</font></blockquote>
<script>
$( "a:contains('DECLINE')" ).css( "color", "red" );
$( "a:contains('APPROVE')" ).css( "color", "green" );
</script>
2. Enter comments if desired
</td></tr>
</table>
