Hello,
1 - It was related to a extra semicolon which, for an unknown reason, was affecting the display in your website but not in other websites with the same browser.
We fixed that issue and we updated the HikaShop packages to include that fix.
2 - Your template is overriding the rules of hikashop.css file.
When HikaShop set background colors for the buttons ; your template bypass these rules and force them to be grey.
Unfortunately, there is nothing we can do in our side for that.
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.