You may need to use our JS and CSS assets. These files are available on e. g. for a domain classic.shoptet.cz https://cdn.myshoptet.com/usr/classic.shoptet.cz/user/temp/frontend_master_main_cs_4505943f2a89163a3590d37682e91bd2.css unique hash just before file extension changes quite often (no less than a few times a week depends on a release frequency).
Now we provide stable url in a form of https://cdn.myshoptet.com/usr/YOUR_DOMAIN/user/temp/frontend_master_main_LANGUAGE_CODE.css. Replace LANGUAGE_CODE with the country code of your project e. g. cs, sk, hu.