Hi, first of all, I'm new to freelancer but i have been debugging stuff for 4 years.
Diving in to your website, I checked and inspected every elements if there are error on script. Luckily none, but when i validate the stylesheet or CSS of your site, It shows many error. this could be the reason of the site loading oddly, However there is a very specific script to solve your problem, Its a jquery script.
Let me know if you are interested and hope to hear from you.
Cheers.