Hello,
First, note that you can select different quantity display, in HikaShop Configuration, Display tab and in Product options part, with the Quantity input method option :
Now, you can adjust your display by adding your Css (like in this
documentation
)
And at the end of your frontend file css add these css commands :
input.hikashop_product_quantity_field {
max-width: unset !important;
}
div#hikashop_product_quantity_main td[rowspan="2"] {
display: table-cell !important;
}
Hope this will help you to adjust your display issue.
Regards