Constant ORDER_FORM_SUBMIT_BASE 

pub const ORDER_FORM_SUBMIT_BASE: &str = "inline-flex h-10 w-full shrink-0 cursor-pointer items-center justify-center rounded-[var(--control-radius)] \
                                          text-sm font-semibold transition-colors outline-none focus-visible:ring-[3px] focus-visible:ring-ring/50 \
                                          disabled:pointer-events-none disabled:opacity-50";

The submit button’s geometry; colour is OrderSide. Not a Button variant because the kit’s Destructive names a consequence, and selling is not one — it is the other half of the same intent.