Tapping on an input field in Safari iOS will automatically zoom to that input field. This can be a jarring experience and mess up the desired page layout when in that zoomed-in state.
How to Fix It
To stop this zooming from happening, all you need to do is set the font size for all input elements to
16px or larger.
16px or Larger?
It is default Safari behavior. The browser will zoom to the input field if the font size is less than
16px—presumably to address legibility concerns.