Hi,
I have experience in the specific field your are looking for. Any kind of modification can be done here. I have done several OPENCART based online store having lots of modification in pages like Product, category, Cart page etc. So it would not be a difficult thing here. Even custom design can also be implemented in OPENCART store. I am developing extensions as well for OPENCART.
Thank you for taking the time to read my application. And kindly revert me with your comments on the same.
Thanks & Regards,
Sumanta