You can change the default Wordpress popup style by overriding it in HeadCSS:
Popup wrapper’s class name is wpstory, style:
.wpstory{ border-left:8px #ff9933 solid; overflow:hidden;}
Wordpress title/heading:
.wpstory h2{margin:35px 35px 0 35px}
Wordpress content:
#storycontent{height:90%; margin:15px 15px 15px 35px;}
Post’s date:
#storycontent h3{font-size:13px; padding:0 margin:0 15px 0 0px;}
Print button:
.wp_print_btn{
display:block; position:absolute; right:15px; bottom:12px;
width:75px; height:25px;
background-image:url('http://static.cdn.realviewdigital.com/global/v3/images/wp_print_btn.png')}