Hamburger menu not working on iPhone 5SE? : I have been going in circles looking for a solution to a problem I never thought could exist in 2019. 

I am busy building a site and made use of the Hamburger menu for smaller screen sizes. Everything looks good in Google Dev tools for multiple devices, but once I do a real world test on my iPhone the hamburger menus is dead, and the styling of the "Order now!" button is messed up? 

Is there an easy way to change the css or JS so that the site can work on ios?

The site is under construction but you can look here to see: http://www.encoreservices.co.za/ESMS/index.html