I have a website on mobile that keeps zooming in when users tap on the keyboard to quickly. How do I fix it so it no longer zooms, but stays static?

my website (http://thewordshift.com) on mobile I have this issue where if some one double clicks quickly it zooms in. however I don’t have this issue on desktop. is there any code I can implement to make it static

I have edited the css and js to be more mobile friendly but still have the same problem