I am on 10.9.5 and using an hd screen

if you look at

View post on imgur.com

the top one is firefox, the bottom one is chrome

then if you look at

View post on imgur.com

the top one is http://kriesi.at/themes/enfold-construction/

while the bottom one is my site

so, on the same version of firefox , the demo on your site looks good, while the imported demo has too small a header on a hd screen

so I guess something differs

by the way, I think I found a bug:
when you press “Add new Category” inside Portfolio Categories
the categories don’t refresh, you have to reload the page to see it was added
(not that it is a problem for me, but it is always nice to have someone testing and reporting)

thanks

eric