No, the width decreases from 46px to 38px and it’s centered causing the left/right areas.
Ok, Now I realised that are missing some brackets to open and close the media query.
Add this one please
@media only screen and (max-width: 991px){
.product .cart-overlay .shop-actions .jckqvBtn {
width: 46px!important;
}
}
-Rui