Edit size of quantity input field

-- url of the page with the problem -- : www.niagaraparkit.com/oztimbertreasures/.../product/3-banksia-1
-- HikaShop version -- : 3.2.0
-- Joomla version -- : 3.8.0

Hi,

I try to edit the size of the quantity input field on the product display page.
I am aware that it is css related.
I had a look at > Display > Views > Product - in files like 'quantity' etc, that I could find listed by using 'inspect'.
However, in these files I could not find the line where the size for the product quantity field is set.

Would you please be so kind and point me to the relevant part.

Many thanks,

Thomas Boepple

Am I correct in assuming I have to create a custom.css for the template for this:

}

table {
max-width: 100%;
background-color: transparent;
border-collapse: collapse;
border-spacing: 0;
}