data dots shift when using cartodb.js

As you can see this is a tutorial example map. It works strangely on my own website. The Florida location is now shifting down a little bit. In fact, all of the dots shift down a little bit.

How do I implement it? I simply copy the js code. And use wp_enqueue_scripts to include the cartodb.js and my own js. Since the map not shows up if I use width: 100%; height: 100%; so I explicitly set the px in css file like this:

#casemap{width: 1000px; height: 600px; background: black;}

Here is my php code.

<?php /* Template Name: Casemap */ 
get_header(); ?>
    <header class="page-header">
        <h1 class="page-header-title"><?php the_title(); ?></h1>
    </header>
    <div id='casemap'></div>
<?php get_footer(); ?>

PS, No JS error in my browser console.

Here is the tutorial website: http://ift.tt/1s3HqIE

Here is url to the tutorial code: http://ift.tt/1EZos81