Disable Dynamic text resizing and breaking layout

Hi
I want to disable the end-user being able to resize text on my webpages via Dynamic Type. EG When a user sets text-size to really large in their iPhone settings, the larger text breaks my layout on the webpage. Yuk. OR When a user on a desktop uses the keyboard to increase text size (Command+).

Is there a way of disabling this function via css or something?

I tried:
body {font-size-adjust: none;}

But that didn’t work
I’m pulling my hair out here!

Thanks!