Hi,
The page IS already responsive and cannot be "more" responsive.
Now please provide a screenshot in order to illustrate your issue with the editor ; because I think that you're issue is just related to the editor (in javascript) which is not fully compatible with responsive design.
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.