Fields inside Div assume different widths even when 100%

Hello all!

In my website I have a div with three components that should assume the full width of the container (and therefore the same width).

In most screens it works just fine, but on my wife’s iPhone 15 there’s an weird difference in the width.
As seen below:

Here you can see how it looks on my Pixel 6a:

If anyone can help me that would be great,
I’ve been bashing my head on this for more than a day!


Here is my site Read-Only (happening only on the mobile breakpoint)
(how to share your site Read-Only link)