<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no,minimal-ui">

https://github.com/ampproject/amphtml/blob/master/spec/amp-html-format.md#required-markup

This probably has something to do with 300ms click delay or rendering issues, but user-scalable=no is known to cause accessibility issues, is it worth the compromise?

Since minimal-ui is also a legacy keyword used by iOS Safari (added then removed), I am not sure why it's recommended neither.

Let me know if I should be asking this on StackOverflow.