Menu not visible/collapsed on Smartphone

Hello, First I want to say that I like the Evolve Drupal 7 theme very much! Compliments on your side! I have a problem with the visibility of the menu on my Smartphone. I must rather say...I can see the stripes of the menu but that's all. It doens't show any menu items when I click on it. However I put the right visibility settings I suppose, I put the website online: www.pjderks.nl ( for your information: The only thing I changes is some additional class setting in my preset1.css stylesheet) Can you please take a look at it? Best regards... Pieter-Jan
I asked several people, no problem:-)) I think this is not an issue of the theme, but an issue of my device-standard browser. The other browser on my smartphone shows everything the right way. The standard browser didn't. Sorry bothering you...
What kind of phone and browser are you using for testing? I just access to you site but it is under maintenance mode, so I cannot check the menu.could you please send you admin account and ftp info to [email protected]?I will help you to check and fix the isssue. Moreover, the theme is using less for style,so if you want to add your custom css, please add it to any less file under lessc folder.don't add it to css file as you did. Thanks.