Close Button in code

I'm trying to include a close window button beneath my storyline interaction. I'm jumping into the HTML code to insert a very basic close link:

<div align="center"><a href="javascript:window.close();">Close Window</a></div>

However, I can't quite pin down where in the code this needs to go. I'm doing the usual places - right above the close body tag, etc, and the link shows up at the very very bottom of the browser window. I need it to be a space or two below the interaction window.

Any ideas on where this needs to get inserted into the code or if there's an easier way to do this?