Hi,
I move your post from the section "HikaSerial" to the section "HikaShop".
Your question does not concern HikaSerial so it would be better in the right place !
Please check your checkout workflow (for the "coupon" step) and I think that our FAQ on the "Styling of the display (CSS)" could help you.
www.hikashop.com/en/support/documentation/faq.html#css
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.