I think I have solved it. Here is the solution.
To make the signature align to the bottom of the post contaier and have a top border too. Make these changes:
#spMainContainer .spTopicPostSection {
color: <?php echo($userColor); ?>;
background: <?php echo($userBackGround); ?>;
border: <?php echo($userBorder); ?>;
margin: <?php echo($postMargin); ?>;
overflow: hidden;
padding: <?php echo($postPadding); ?>;
<?php echo($smallRadius); ?>
position:relative;
padding-bottom: 40px;
}
#spMainContainer .spTopicPostSection .spPostUserSignature {
padding: 1em 1em;
font-size: <?php echo($spPostUserSignature); ?>;
border-top: 1px solid #ccc;
bottom: 0;
position: absolute;
width: 100%;
}
What I basically did was made the container TopicPostSection position relative and increased the bottom padding to 40px.
In the signature div
– added bottom:0, made position absolute, defined width as 100% and increased padding from .5em to 1 em.
Also added the top border:
border-top: 1px solid #ccc;
Works fine on my site! 