Find this div around the button
HTML Code:
<div style="text-align:center;">
After change text-align:center; to text-align:center;padding-top:5px;
And the Customize buttons are not available for guests to see, but if you are talking about removing the original button, you just need to locate it in the template (where it was originally) and just delete it, or comment it out with <!--
old button code --> if you just want to hide it from displaying on the page.