In today's world it very important for website themes

In today's world its very important for website themes to work well for desktops, tablets and phones. I have tried three themes, Spirit, Scribe and Panino. The problem I've run into thus far is with the menu system. I need to use drop down menu's for my website application. The drop downs look and work ok for desktop view, but for phone view the drop down's will not show or work, no matter how I set it up in any of the above mentioned themes. Any help on this would be appreciated. Because of this I'm stopping further work on the website until this can be resolved.