Top Navigation Bar

Hi everyone! I′m trying to configure a top nav bar with more than two levels, but I could not. Then I discrovered that there′s another user who has posted this before. After checking their site https://www.floliday.com I realized that they figured that out. I have to say that that′s exacly what I′m looking for my blog and I′d like to know if someone could check it and tell me if that′s a plugin or something to do with CSS. I tried many times to contact them but I got no replies.

This could solve all my problems!
Hope someone can help me!

Thanks a lot.