"Add to cart" button under the quantity after the update.

Hello,

Sorry for the inconvenient, it was a correction as the quantity field is in a div it was a logical and necessary correction for the general structure.
Now,
I will show you how to redefine the display according to your needs.
1. Learn here how to add your css , I suggest to maybe create a custom_style file in order to keep this command even if you update your HikaShop.
2. The Css command to add :

.hikashop_quantity_form {
    display: inline-block;
}