Menu when viewed on Mobile phone?

When my site (with this theme) is viewed on a mobile phone, the menu just says the word Menu and doesn’t do anything if tapped (clicked on)…

Do I need to change some css or something to get this to work or any other idea’s? I can use a separate menu plugin for mobile, but i’d rather not install another plugin if I don’t have to, but then I’d need to make the menu disappear when mobile…

Thanks for the help.

p.s. the web site address is https://www.miraclenet.tv/AlphaOmega