How to solve the problem with the display of button elements on retina displays?

Question

css

All good evening.
Please help, no one to ask.
There is a site sellsay.com/keep-me-updated , specifically at this link there is a form for subscribing to the newsletter.
They asked me to make a button with text and an envelope icon.

Everything I did worked correctly on everything, but then they checked it on the Iphone and then a problem appeared

. I don’t know what to do, can someone tell me how to solve the problem.
Thank you all in advance

Answer 1

The problem is in the icon - it's not a picture, it's an icon font.
a) no line-height set (set 1)
b) positioning by magic numbers
In general, the layout of the element is overcomplicated for unknown reasons (why is there flex if the icon is positioned absolutely?)